Rhonda Patrick: Exercise is no longer at the fringe of oncology. Emerging evidence has revealed that exercise really has become one of the pillars of cancer care, whether we're talking about prevention or treatment. And at the forefront of this research is Dr. Kerry Kernier, who has done a remarkable amount of research looking at how exercise affects cancer outcomes and much, much more. He's a professor and a chair at the University of Alberta in Canada. I'm very, very excited to have this conversation with you, Kerry. I've been a big fan of your research, read many of your studies over the years, and have been looking forward to this conversation with you today.

Kerry Courneya: Thank you for having me, Rhonda. It's a pleasure to be here.

Rhonda Patrick: Well, I was thinking maybe we could kind of start at the top and just talk a little bit about why effortful exercise is not only beneficial for cancer, but also for health in general.

Kerry Courneya: Yeah. As you know from previous podcasts, exercise has a lot of benefits for the cardiovascular system, the muscular system, the immune system, and many other organs benefit from exercise. So it's really one of those behaviors that has positive health benefits throughout the body. And the improvements in those health parameters throughout the body really reduce the risks of various chronic diseases and help you manage those chronic diseases if you are diagnosed with them.

Rhonda Patrick: So maybe we can talk a little bit about cancer prevention. You often hear about how cancer prevention occurs decades before you get a diagnosis from your research. What is the single best lifestyle shift that someone can do right now to positively affect their lifetime cancer risk?

Kerry Courneya: Every year in the U.S. about 2 million Americans are diagnosed with cancer. And the American Cancer Society estimates that about 40% of those cancers could be prevented if everybody followed sort of the optimal lifestyle suggestions that they make. So we could reduce those 2 million diagnoses every year to about 1.2 million. So they're not all preventable, but we could certainly prevent a bunch of them. So number one on the list, I'm sure everyone will know, is smoking. That's the biggest risk factor for cancer, and it's the one that many of the public health people have focused on for many years. Reducing cancer rates, making great gains in cancer, reductions in cancer rates because of reductions in smoking. Assuming you're not smoking, which is 80 to 85% of the American population, obesity is actually the second on the list of risk factors for developing cancer. Unfortunately, obesity is going in the other direction. As smoking rates go down, obesity rates are going up. So we're starting to see more obesity related cancers. Assuming you're not smoking and you're not obese, next on the list is actually alcohol consumption. You might have heard of the surgeon general's warning recently about the link between alcohol and cancer that many people are not aware of. So there's a lot of alcohol related cancers as well. After those sort of big three lifestyle changes. Yes, exercise and diet are important and exercise has been shown to reduce the risk, you know, maybe 8 to 10 of those cancers. There's over 100 different types of cancer, so it's a very complicated disease, all different cancer types. But, but we now have evidence suggesting that exercise will lower the risk of getting some of those cancers, particularly colon cancer, breast cancer, endometrial cancer, and several other cancers as well, such as stomach cancer, esophageal cancer and a few others. So yes, some evidence that these lifestyle chances really can reduce your risk of.

Rhonda Patrick: Getting cancer if someone had limited time and resources in the sort of 80, 20 sense. So if you were going to put in 20% of your effort to kind of get 80% of the reward, do you think that, you know, what are some of the prevention strategies that would give you the biggest bang for your buck, like cancer screenings, exercise, things like that.

Kerry Courneya: So for sure, if you're a smoker, that's absolutely the best thing you can do is quit smoking and you can really substantially reduce your risk by quitting smoking. And it has been fairly quick benefits in terms of lowering cancer rates. If you're obese, then yes, going on a weight loss program and reducing obesity would be the biggest thing. If you're a heavy drinker, then that's going to be a key thing. Assuming you're none of the above, you're not particularly overweight or smoking or drinking heavily, then I think exercise really is next on the list. And you know, the general recommendation is the public health guidelines of about 150 minutes per week of moderate to vigorous intensity aerobic exercise. Some evidence has suggested muscular strength training can lower the risk of some of these cancers as well. But most of the recommendations are really around sort of moderate to vigorous intensity physical activity.

Rhonda Patrick: Do you find that these recommendations are so like, if you're going to do aerobic exercise versus like the resistance training or high intensity interval training, do you think there's any differences between them or is it really just kind of do something?

Kerry Courneya: Yeah, I don't think there's large differences in terms of the length. So, you know, ultimately exercise is energy expenditure. So you're causing the system to engage in energy expenditure and that has a whole sort of cascade of biological effects that occur. They're a little bit different. If it's strength training, we know there's going to be particular adaptations, or if it's aerobic exercise, there are going to be other adaptations. But in terms of some of these biological changes like the anti inflammatory effects, the stimulation of the immune system and stuff, doesn't seem to matter which type of exercise. Certainly some support for more. The moderate intensity exercise is having more of a stimulation effect on the biological system.

Rhonda Patrick: So you want a little bit of a stronger stress to cause that immune. Immune adaptation for example, or the metabolic adaptations.

Kerry Courneya: Yeah, exactly. So all these recommendations will generally be at the level of at least moderate intensity. There's definitely been some research on the light intensity physical activity just getting up and moving around and what are some of the benefits and outcomes related to that type of exercise. But more compelling evidence once you get into the moderate intensity exercise zone, and certainly even more benefits with the vigorous intensity or the higher intensity exercise.

Rhonda Patrick: I know the major area of focus of your research is looking at how exercise affects cancer treatment, but there are some interesting questions I have with prevention as well. You're mentioning obesity being a big risk factor for a variety of different obesity related cancers. And perhaps there's people that have genetic predispositions, maybe they have some of these BRCA1, BRCA2 single nucleotide polymorphisms that may increase the risk of breast cancer, for example. Is there any evidence or do you have any opinions on whether someone that may have those risk factors if they incorporate exercise into their personal hygiene, is that something that can help negate some of that cancer risk, even if they still have the genetic predisposition or even are obese, for example?

Kerry Courneya: Yeah, there is good evidence on that. So one of the mechanisms how exercise might lower the risk is through managing obesity. But what we also see is exercise lowers the risk of cancer regardless of your obesity status. So we can do the subgroup analysis of Those who are BMI above 30, overweight, calorie, healthy weight, all of them show a reduction. So obesity is not the only mechanism by which exercise is lowering the risk. So even if you're obese and you don't lose weight, exercise can help you lower the risk of developing cancer. We even see this with smokers. So we can break them into sort of the smokers and the non smokers with lung cancer risk. And even those who are smoking, exercise will help them lower the risk. Of course that's small compared to the impact of not smoking, but it shows that exercise works within these groups to lower their risk. Whatever is kind of driving your risk, Whether it's obesity, whether it's smoking, you can benefit from it. The genetic stuff, we haven't seen quite as much evidence yet. You know, the BRCA genes you talked about, there is like an 80% chance of getting breast cancer and very high with ovarian and some of these other ones. So you're almost on a kind of genetic trajectory that would be very hard to stop, you know, with a lifestyle change. So I haven't seen as much evidence there suggesting that it can be beneficial for those patients. There's other options for those patients in trying to reduce their risk.

Rhonda Patrick: Yeah, that was probably the most extreme genetic predisposition case. I mean there's other, other genetic predispositions as well. Or maybe a family history. If someone's got like a family history.

Kerry Courneya: And we've seen some of the studies look at that, trying to look at kind of. And just do it, as you say, by family history. A very simple way of looking at. And we do find that exercise lowers the risk of developing some of these cancers. Even in those who have a family history.

Rhonda Patrick: There's, it seems like it's really just a panacea. I mean, in some regards. Obviously if you're a smoker, you don't want the take home message to be I'm going to exercise but still smoke. Right. Like, no, like you should, you should quit smoking. Right. That's like the number one thing. But the fact of the matter is, and I'd love to get into some of these mechanisms in a minute about how exercise is, how it's playing a role in cancer prevention and affecting tumor biology through metabolic signals. I mean, glucose regulation being a big one. Right. I mean, even if you're someone who is obese and you're exercising and you're increasing glucose uptake into your muscle, I mean that's very beneficial to not have it then available for a lot of cancer cells which primarily do use glucose for fuel. Yeah. So what about someone who is, let's say, not obese, they're healthy, maybe they're in their 40s and they're someone that's more like a weekend worrier maybe. I don't even know if that would be the term. Maybe there's someone that just goes for a jog on the weekends only. Would there be a case to make for those people to maybe push a little bit higher intensity than just going for your, your jog on the weekends in terms of like making an impact on their cancer prevention?

Kerry Courneya: Yeah. So what we see in the cancer Prevention literature is there is a dose response association, as we say. So that means the more exercise you do, the greater the risk reduction. So even though we can kind of look at different cut points and say, here's kind of amount of exercise that will give you a benefit, we know that more is better. And there's various ways of getting that more. One of it, as you pointed out, is increasing the intensity, but also increasing the frequency or increasing their duration. And what you see with the exercise guidelines nowadays, if they've almost backed off. Any recommendations in terms of the frequency, duration component, doesn't really matter how you slice and dice that exercise. So this guideline of 150 minutes per week, we used to say five days per week for 30 minutes. And then we used to say, okay, well, spread it out over at least three days and in minimum durations of 10 minutes. And now they're not even saying to spread it out over multiple days, and they're not even saying it needs to be a minimum of 10 minutes at once. So the whole weekend warrior thing brought that. Well, you can probably go on a Saturday and Sunday and do 50 minutes, you know, if you're out doing a hiking or some other activity. And that might be just as beneficial as spreading it out over different days. Now, that's on the prevention side of things. Things get trickier, I think, on. On treatment side of things, where maybe, maybe more frequent bouts are important because you're looking at the acute effects of exercise. Accumulating acute effects. But in terms of the general prevention strategy, the. The more you do, the better. And it doesn't really matter how you slice it up over the course of a week, as long as you get to that 150 minutes.

Rhonda Patrick: Is there a limit on that? So we're saying 150 minutes of moderate intensity exercise. You know, depending on where you, what journal you read for the definition of moderate intensity exercise, you'll find it's, you know, your heart, your heart rate max is going to like, what, 70%, 75% heart rate max. So, I mean, you're getting some sweat on your brow there. If you were to do, let's say 300 minutes a week, you were to double that of moderate intensity or you were gonna also increase the intensity. Right. So you're doing more vigorous types of exercise. You're going above that 70, 75%, you're going to 80% max heart rate. Would you continue to see decreases in cancer risk in that? I mean, is there a limit? Like, does it.

Kerry Courneya: Yeah, it's a good question. So the general recommendation is actually 150 to 300 minutes. So, you know, 150, we kind of use the minimum to getting these benefits, and then those benefits will continue to accrue up to about 300 minutes. And then the curves kind of plateau after that. You know, you can certainly do more than that, but in terms of bang for your buck and really getting the benefits is getting up to that 150 minutes and then further increases as you get to 300 minutes. But it does kind of plateau after that.

Rhonda Patrick: Okay, so really it's better to be on the higher end of the recommendations, whether that's, you know, the moderate intensity exercise, 300 minutes a week, or vigorous intensity. The higher end being what, 150 minutes?

Kerry Courneya: That's right.

Rhonda Patrick: Okay.

Kerry Courneya: Yeah. So it is viewed more as the minimum of achieving that. And all these guidelines note that further benefits can be gained by doing more. So we set that guideline around 150. And additionally getting up to 300 can be more. And generally the guidelines just sort of double weight, vigorous minutes. So when we say it can be 150 minutes of moderate or 75 minutes of vigorous, you kind of get double credit for the vigorous intensity exercise or any combination of the two. It doesn't have to be all moderate or all vigorous. You can mix it up as well. But that's roughly the extra benefit of the vigorous is this kind of double weighting that you're probably getting about twice the benefit as you might get with moderate intensity exercise.

Rhonda Patrick: It seems as though people that, let's say, do have a family history of cancer would really benefit from knowing this information as well as their physicians that they speak with. Because you would imagine someone with a family history would want to hit the top end of that recommendation. Right. And so. And not the minimum. So you often only hear the minimum when hearing recommendations, which I don't really, I don't think. I think that's kind of, you know, a problem, to be honest. I think we should be talking about more of the upper end, especially if you're getting a dose response and people really do want to get and maximize their, their benefits that they're going to get from exercise. For someone who is exercising and has been and say they still come down with cancer, is there any preemptive benefits they get? So in other words, like, does the fact that they've been, let's, you know, say exercising for decades before their cancer diagnosis, does that seem to change the trajectory of their, their outcome at all? Like, do they have a benefit?

Kerry Courneya: It's A great question. And so there is some studies that link both pre diagnosis exercise and post diagnosis exercise to better cancer outcomes. And some of those studies show that, yes, even the amount of exercise you were doing before diagnosis might improve your outcomes after diagnosis, independent of what you do after diagnosis. Some of it is that the exercise might also alter the cancer itself. So even if it doesn't prevent the cancer, it might be a less aggressive cancer or a genetically different type of cancer, or it might be more of an early stage cancer. So some of it's related to changing the cancer itself. But even if exercise doesn't prevent the cancer, it may delay the cancer. So someone who gets diagnosed at age 70 might say, hell, I exercise all my life and I still got cancer. But they might have been diagnosed at 65 without the exercise. So sometimes it's just delaying the cancer. And then I think the pre diagnosis exercise helps you get fit and ready for cancer treatments. And so you can think of exercise kind of this whole pre diagnosis time as the entire pre habilitation part. It's preparing you for getting diagnosed with these chronic diseases. Because once you get diagnosed with a chronic disease, sometimes the treatments happen fairly quickly, and that window of getting fit and ready for the chronic disease and its treatments might be short. So the other way to look at this sort of prevention lifestyle one is really prehabilitation for the eventuality. Most Americans will be diagnosed with a chronic disease at some point in their life, and many of them will be diagnosed with multiple chronic diseases. It's the rare person that's going to make it to age 90 with no chronic disease. So you are kind of preparing for those chronic diseases and getting yourself into the best shape and the best fitness for then having to deal with that chronic disease. So, yeah, lots of benefits, I think, to exercising throughout your lifetime, even if it doesn't ultimately, you know, prevent you from getting a particular disease.

Rhonda Patrick: What kind of exercise prepares people the most for a cancer treatment that they're going to undergo? I mean, we're, you know, strength training, resistance training is obviously you, you do get your heart rate up. It's not the same as aerobic exercise or vigorous intensity, high intensity exercise, but you're building muscle mass, you're building muscle strength. Very, very important for aging. Where does the aerobic versus resistance training come into play in terms of preparing someone for a cancer diagnosis?

Kerry Courneya: So most of the research we have has been on the aerobic side of things. So somebody gets diagnosed with cancer, they do oftentimes go onto these treatments fairly quickly. So it can be a short window in terms of getting ready. But prehabilitation is this very important concept that you can prepare for these treatments and potentially reduce your complications, reduce your length of hospital stay, Improve your quality of life and your recovery afterwards. Most of the studies have looked at fairly simple aerobic programs, Walking programs, and oftentimes they're combined with nutrition, psychological counseling, stress reduction. In the general literature, these programs have been shown to be effective for patients going on to surgery, onto a major surgery and showing that they have fewer complications from the surgery, Shorter hospital stay. In the cancer area, we haven't demonstrated quite as strong of benefits. We can show that if you get some exercise before surgery, that you are fitter prior to surgery and that you end up being fitter and able to function better physically after surgery, but not really the reductions in, say, length of hospital stay or the complication rate, which is some of the key outcomes that we're seeing in other surgical endeavors.

Rhonda Patrick: Got it. Yeah. I would imagine also if there would be some evidence looking at resistance training added onto that, it would be beneficial because, you know, post surgery in particular, you're. You're less mobile after. Right. And, you know, so you end up losing muscle mass. And it's really hard to gain that muscle mass back after. After. At least when you're older after an event like that.

Kerry Courneya: Yeah. The muscle mass in cancer is critical. Cancer can become a wasting disease. This phenomenon called cachexia, where you get muscle wasting, Especially once you get advanced or metastatic cancer. But now there's a lot of research showing that low muscle mass is really the critical thing driving risk of recurrence and death from cancer. So these patients who have low muscle mass or lose muscle mass when they're going through these difficult treatments Tend to have the worst outcomes. So it's prompted a lot of research now into the resistance training angle versus the aerobic exercise angle.

Rhonda Patrick: Wow. Does resistance training counter cancer cachiacs? I know that's a little bit of a different mechanism. Is that an inflammatory driven mechanism that's breaking down muscle?

Kerry Courneya: Yeah. I don't think they know all the mechanisms right now of why that's going on, but they've attempted to address it mostly with nutritional interventions and supplement types of interventions, but not had great success. There is some research looking at exercise and strength training Seems to have modest benefits, But I think ideally we'd want to intervene earlier and prevent patients getting from that condition, cachexic state, because then things, you know, progress very rapidly Once you get into that cachexia. And it's very Hard to reverse it at that stage. But if we can prevent it up front and delay it, I think that would be a really important benefit.

Rhonda Patrick: Yeah, that's a really good point. I mean, on the prevention stage, it would be. You have to be incorporating regular resistance training, strength training into your workout routine because you want to have. You want to basically build up that muscle reserve that you have more to pull, pull from if a terrible thing like a cancer diagnosis occurs. And cancer, cachexia, I don't know exactly what drives it all, but if it, you know, kicks in, at least you have more muscle to start with. Right. Like that would be.

Kerry Courneya: And there is. And of course, that feeds into the whole obesity paradox. Right, which is obesity is a risk factor for getting a chronic disease, but it actually helps you live longer after a chronic disease. So we've seen that in a few of the studies, say with lung cancer, that once you're diagnosed with lung cancer patients who are actually larger, more obese have a little bit longer survival. And I think it gets into this idea of the reserves that you've built up and sort of this rapid decline that's going to occur. I think the obesity angle may be important, but it's probably even more important with the muscle mass. Right. The larger amount of muscle mass is going to help you live longer, you know, as cancer sort of takes this toll over the course of months or years.

Rhonda Patrick: Do people with obesity also have more muscle mass? Are they just eating more calories, including from protein, which is a signal for muscle protein synthesis?

Kerry Courneya: Yeah. And the research shows there's no necessary link between that. There is this phenomenon we call sarcopenic obesity. So there's high rates of obesity, but those people have fairly low lean body mass as well. So there's different kind of phenotypes, if you will, of the obesity. And you're right, the real issue we want to look at in obesity is how much muscle mass versus how much fat mass. And look at kind of that fat to lean ratio. And that's really the more important factor. Some people who have very high weight might have a lot of muscle mass and be in very good shape. Others might have a balanced muscle mass, and then others might have very small muscle mass to. Despite these high levels of obesity.

Rhonda Patrick: You know, the other thing I wonder, Carrie, is oftentimes you'll. You'll see in some of the scientific literature, obesity defined as a BMI of X. Fill in the blank. Right. And if they're measuring bmi, you know, some people that are lifting weights, that are very muscular have a high bmi. And if you were just to look at BMI only and not like hip to waist radio ratio and other factors, you might actually miscategorize someone as obese. And so I wonder, it'd be interesting to see if there's anyone that's looked at this obesity paradox and whether or not that's contributing to confounding that data.

Kerry Courneya: Yeah, and that's definitely one of the explanations for the obesity paradox. And that is it's not a good quality measure of body composition. So in our research and other research, we'll either look at DEXA scans that allow you to look at fat mass and lean mass, but what they've done in the cancer field is all these patients are getting scans to track the tumors, and these scans will go through the skeletal muscle in different places and they're able to get really good quality measures of how much skeletal muscle mass you have. And they've, they're the ones who have pointed out that's really what's driving these survival rates is this low muscle mass, which also drives low physical functioning and poor quality of life as well. So I think, you know, in the cancer field, muscle mass and strength training are turning out to be critically important.

Rhonda Patrick: Yeah, that's really not something that at least, you know, in the past decade or so or more was really talked about, at least within the context of why it's important to be fit with a cancer diagnosis. Right. Usually you think about aerobic exercise and the stress of aerobic exercise, and of course there's all these mechanisms that occur. But it is really interesting to think about how important having that muscle reserve is if you are going to get diagnosed. Because, I mean, it really does affect. It affects the trajectory of almost any kind of illness. Not just cancer. I mean, a respiratory illness, a certain surgery, anything that's going to have you immobilized for a period of time because you're, you're recovering or, you know, anything like that. So I know for myself, I've really gone on this personal journey. I've always been really into endurance training. I've loved being, you know, outside and running. That's been something I love to do for many decades. But in the last year, I've taken strength training, resistance training, really serious. And, you know, I'm doing, I'm doing. I went from doing like 30 minutes a week to like two and a half hours a week of resistance training. So I've really gone up on, and we're talking, you know, compound lifts and things that are. That Are working multiple muscle groups at once and joints and affecting strength as well as, you know, bone density and everything like that.

Kerry Courneya: Yeah.

Rhonda Patrick: Okay, so I want to get into exercise treatment in a minute because I know that's really where the bulk of your, your research is. But a couple more questions before we get there on the prevention side. So I've talked to some people and I've heard them say things like, oh, I do a lot of house chores, I walk around, I'm on my feet at work, therefore I'm getting enough exercise and I don't really need to make structured exercise a part of my physical fitness routine. What would you say to that in terms of affecting cancer risk?

Kerry Courneya: Well, the Recommendations for the 150 moderate intensity exercise minutes per week is above and beyond sort of what we call background activity, just sort of what you might do over the course of the day. So getting up and moving around is important, but it's not a replacement for a structured exercise program. The way I think of it is I view those types of things where you're getting up, standing around, you know, parking at the far end of the parking lot and walking in or getting off the bus, stop a stop early to get a little bit of walking in. I view those kind of as activity supplements to be added to a good quality exercise program. Just the same way when you talk about nutrition, you know, you don't live on nutritional supplements, right. You want a good quality healthy diet. And then you might take nutritional supplement, depending on health issues. So at the core of exercise is a good quality structured exercise program combining aerobic and strength exercise. Then on top of that, yes, getting up and moving around, not sitting for extended periods of time and building activity into your day I think are also important.

Rhonda Patrick: So you're hitting on my next question, which is the concept of exercise snacks, because there's some studies that I've read where sedentary time, so the time that you're sitting at your desk or sitting down at work accumulates and that sedentary time is an independent risk factor for cancers, which kind of raises the question of whether or not if you do these sort of structured exercise snacks where you. Every hour, so you get up and you do a minute of high knees, or you do some, some, you know, burpees or jumping jacks or whatever your favorite exercise snack is to kind of get the blood flow and break up that sedentary time. Is that something that would be beneficial?

Kerry Courneya: There's a little bit of research supporting it. It's not as strong as the Moderate to vigorous intensity exercise. So if I had to rank them, you know, that would certainly be above the sedentary behavior part of the challenge. In those studies. It's very, very much harder to measure measure, you know, all these little things that people do over the course of the day where they're a little bit better at recalling vigorous intensity and moderate intensity exercise. But nevertheless those movements are going to be beneficial because we know they are going to expend energy. So it's going to be similar to these other exercise benefits. And as I mentioned, you know, we're no longer recommending this at least 10 minute duration as the minimum of a of exercise break. So if it's moderate intensity and you're able to accumulate it in a few minutes here and a few minutes there, there could be beneficial effects of that type of exercise.

Rhonda Patrick: I think there's some evidence showing that as well. At least with the, the vilpa studies, the vigorous intermittent lifestyle activity where people are accumulating these short bursts of a couple of minutes throughout the day all the way. I think they accumulate up to between six and nine minutes of that. You know, the short bursts of intense actually exercise. More intense.

Kerry Courneya: Yeah, yeah. No, it's very interesting research. And there, of course, they're using the objective accelerometer so they're not relying on the person's recall and they get a better indication of that. But yeah, if you're engaged in this type of vigorous intensity exercise, even if it's only for a minute here, a couple minutes there, depending on how much you accumulate during the day, there's going to be beneficial effects to that.

Rhonda Patrick: So you mentioned supplements. People take supplements sort of as insurance. And it's funny because I've even used that term before. Like I take a multivitamin. There's a lot of trace elements and minerals in there that I may or may not get from my diet, but it's kind of like an insurance that I'm at least going to get some of these minerals and elements that I may not be meeting the recommended intake for. And I think of exercise almost as like the best long term insurance for reducing my cancer risk. Would you agree with that in terms of.

Kerry Courneya: Yeah. In the absence of smoking and obesity. Yeah. Exercise is really important for lowering the risk of cancer. Yeah.

Rhonda Patrick: Okay, so let's shift gears and talk about the role of exercise in cancer treatment. Maybe we could start just a little bit with explaining this sort of cancer treatment landscape. Like when someone's newly diagnosed with cancer, like what kind of treatments are they potentially Looking at for these different types of cancers.

Kerry Courneya: So there's been a lot of exciting progress in cancer treatment over the last couple of decades. You know, the mainstays of cancer treatment in the past were surgery, very important radiation therapy, chemotherapy, and hormone therapies. And now over the last couple decades, there's been a lot of research on so called targeted therapies and immunotherapies. And these have really changed how these patients are treated. What it does mean, though, is many of these patients are in for extensive treatments. I think cancer patients are probably the most heavily treated chronic disease group that we have. So patients get what we call multimodal treatment. So it's rare that you would only get one of those treatments. And some of these patients get surgery followed by radiation therapy, followed by chemotherapy, and then they may get immunotherapy. There's over 100 different types of chemotherapy drugs with all different side effects. There's dozens and dozens of immunotherapies that are now approved. So patients get treated with all these combinations and sequences of these treatments. So it's not a quick and dirty sort of disease where you're in the door, you're treated, and you're out. These treatments go on for many months and in some cases, many years. So patients kind of face this treatment gauntlet, and it can take a physical toll and a mental toll on these patients over an extended period of time. And when you get into advanced cancer, which you might have for many, many years, we have what we call first line treatments, second line treatments. In some of these cancers, we have sixth and seventh line treatments. So you're looking down, knowing that ahead of you, you've got all these different treatment options that may be available. They help with the cancer, but they do have a lot of side effects. And, and so it can be a real challenge to go through these cancer treatments.

Rhonda Patrick: How does that complicate the role of exercise in the cancer treatment?

Kerry Courneya: Yeah, so we have to think about exercise as a cancer treatment. So that means we have to think about combining exercise with other treatments and sequencing exercise. Is exercise more beneficial before this treatment, during this treatment, after this treatment? And what treatments, what treatments does exercise add benefit to? And which treatments does exercise not add benefit to, or what treatments might it interfere with? So this sort of old straightforward question, does exercise help with cancer? You know, sort of was in the days of independent of any other treatments. Now that all these other treatments are being given to these patients, we have to think about exercise in a little more sophisticated way, about when and how we Combine exercise with these other treatments that patients are receiving.

Rhonda Patrick: I've heard you say, don't take cancer lying down. How do you. How does a patient who is newly diagnosed with cancer, who is scared, confused, how do they transform that fear into motivation to exercise? You know, how do they transform their fatigue into that motivation to move and exercise?

Kerry Courneya: Yeah, so a cancer diagnosis is a very difficult time. These patients can be overwhelmed and very stressed to find out you have cancer. And then they're learning what type of cancer, what stage of cancer they have, what's the grade of cancer. And then the oncologist is talking about all these treatments. We're going to give you, you six months of chemo, and then we're going to put you on hormone therapy. So it's a very overwhelming and difficult time. And so we have to look at, you know, what's the opportune time to present exercise to these patients and help them intervene. But I think many patients tell us that cancer makes everything feel abnormal. They lose control. It's just the cancer has taken over. And many of them feel that exercise helps them maintain control, helps them feel normal. So once they kind of settle in the initial shock and realize they have cancer and they're in for these series of treatments, many of them start looking for, what can I do to help myself? Yes, I've got to show up and get all these treatments, but what can I I do to potentially benefit myself? And when they start looking into the literature, exercise is one of these things that they're quickly seeing is potentially very beneficial for them, not just for the disease itself, but yeah, many of these sort of side effects, symptoms, quality of life issues that they're going to face, the declines in physical health and mental health. And I think once they start seeing these cancer specific benefits, Cancer patients aren't motivated to increase their VO2 max or their muscular strength. They want to know what's going to help me get through these treatments, what's going to help me benefit from these treatments, what's going to help me manage the side effects. And once they start seeing the research there that exercise is not just this general health behavior for cancer patients, but it's actually going to help them manage their cancer, that can be very motivating for them.

Rhonda Patrick: So what are some of these effects that exercise can help improve? Whether we're talking about chemo tolerance, side effects, improve, improved survival. What are some of the effects that exercise helps with?

Kerry Courneya: Yeah, so one of the big ones is managing some of these side effects of the treatments. You mentioned fatigue, which Is one of the most important ones. Many cancer patients experience fatigue from these treatments as well as symptoms. And in the past, oncologists used to recommend, take it easy rest. This is the best way to get through these treatments. And so some of the early studies started showing that the patients that rested during chemotherapy actually reported more fatigue than the patients who exercise. And this is very counterintuitive for patients, and it's counterintuitive for doctors. You know, when you're tired and not feeling well, Rest seems like the best medicine, but it's not the best medicine. And we've demonstrated that consistently in the exercise oncology field that patients who exercise going through these treatments have lower fatigue. So that's a huge factor. The other benefits that have been shown definitively Are improvements in sleep quality. So you can imagine the stress and the anxiety of going through these treatments, not knowing whether the treatments are working, Whether or not you're going to have recurrence. Very difficult with sleep and exercise has been shown to benefit sleep quality, Reduce some of the anxiety associated with cancer, Depression levels, and some of these other side effects as well. Peripheral neuropathy. There's been some studies showing some potential benefits. So that's one of the key benefits is managing the side effects. You mentioned treatment tolerance, which is your ability to complete these treatments. Very, very important. Every cancer patient learns very quickly that I need to get all of these drugs that I'm supposed to get, and I need to get them on time. If the oncologist has to recognize reduce the dose of those drugs or delay them, that increases the chances of recurrence. In other words, it reduces the chances of being cured. So the last thing oncologists want to do is sort of reduce these drugs or delay them. But if the side effects are so bad, they have to do that some of these patients, the side effects are so bad they can't complete these treatments. So early on, when we were looking at exercise, the concern was that we might, might interfere with patients ability to complete these treatments that are, we're going to make it harder. You know, we're piling on this exercise on top of all these side effects where they're sick and nauseous and diarrhea and vomiting and so on. And so some of these studies have actually shown that it's the patients who exercise during chemotherapy that end up completing more of their chemotherapy. They have fewer reductions in the chemotherapeutic drugs and fewer delays, and that portends a better outcome, A higher chance at cure, and a lower risk of recurrence. So that's been a huge finding that's very motivating for patients. And then ultimately, this link to survival, you know, does it reduce the risk of recurrence? Does it improve survival? We have a growing amount of research, preclinical studies in the animal models looking at exercise and tumor growth and spread, but also these epidemiological studies showing that cancer patients who report more exercise seem to have a lower risk of recurrence of the disease and a lower risk of dying from the cancer many years down the road. So, yeah, lots of benefits across the board in terms of quality of life benefits and also disease and survival benefits.

Rhonda Patrick: So when it comes to the exercise type, do you think that more intense exercise is more beneficial with respect to cancer treatment and some of some of the, at least mechanisms that may be occurring to have these beneficial outcomes?

Kerry Courneya: So some of it's been showing that the higher intensity exercise is better. A lot of these studies have done high intensity interval training, but it very much depends on the patient's ability and how they're responding to treatments. Some patients will get a very first chemotherapy infusion and they are completely wiped out. They got nausea and vomiting, they have diarrhea, they have sickness, and it's very difficult. So we have to individualize the exercise for them. Other patients don't even know they're on chemotherapy. They continue working and continue going through it, and they're able to do a much more demanding exercise program. But the weight training has also been shown shown to be very important. I mentioned that improvement in chemotherapy completion, and one of the studies that we did, it was actually the weight training group that completed more of their chemotherapy Compared to the aerobic exercise group or the usual care group. And so this weight training group was able to put on over a kilogram of lean muscle while they were on chemotherapy. And this might help with the metabolism of these chemotherapy drugs. So higher intensity exercise seems to be good. Weight training seems to be very good during these treatments.

Rhonda Patrick: What kind of protocols are we talking about with respect to the weight training protocol, the aerobic exercise training protocol that some of the patients in your trials have been on?

Kerry Courneya: Most of the protocols we've tested are three days per week of weight training, maybe eight exercises covering all the major muscle groups, moderate intensity, so 8 to 12 repetitions before failure. So I would consider kind of a standard full body type of weight training program. Many of the other trials have done two days per week. So lots of good evidence suggesting that even two days of a week of weight training can Be very beneficial for these outcomes.

Rhonda Patrick: Have you ever combined the aerobic exercise with weight training and see if there's like a, like synergy or additive effect?

Kerry Courneya: Yes, we did one trial we call the CARE trial, which stands for combined aerobic and resistance exercise in breast cancer patients. And we did find some additional benefits. We did a high dose of aerobic exercise, we did a moderate dose of aerobic exercise, and then we did a combined aerobic and resistance exercise. And of course additional benefits in things like muscular strength, improvements in lean body mass, but even in some of the symptom side effects, small additional benefits of combining the two. But the best evidence definitely is exercise compared to nothing at all. That's, that really drives the benefits. And once you start manipulating the exercise prescription, we can see some additional benefits for patients who are able and willing to do more exercise or able and willing to do a combined exercise program.

Rhonda Patrick: When you say high aerobic exercise versus moderate, is this guidelines like per week or what. What was the kind of protocol?

Kerry Courneya: Yeah, so it was 75 minutes of vigorous in the, in the sort of moderate group and then 150 minutes per week of vigorous in the high aerobic. So it was more kind of the minimum guideline versus the, the optimal guideline for aerobic exercise.

Rhonda Patrick: What. So I want to talk a little bit about some of the mechanisms for improved survival for reduced cancer recurrence. I mean, you mentioned one which was continuing the treatment. Right. So obviously that's one of, but perhaps some other ones that may also affect cancer metastasis. Right. Like that would also affect survival and perhaps recurrence later down the line as well. What do you find? Can we talk a little bit about some of these mechanisms like immune related, metabolic related. I've heard you talk about increased blood flow as well. And maybe what's most compelling, if there's any. That's most compelling.

Kerry Courneya: So if we talk about influencing the primary tumor, and we've seen this in pre clinical models, but also in the human studies, sometimes when we've got an existing primary tumor, the first treatment is not to surgically remove it. The first treatment is to treat it with chemotherapy or radiation therapy and try and shrink or eliminate the tumor that way. And so what they've shown in some of these pre clinical models is if you're giving these mice particular chemotherapy drug and exercise versus neither versus both, exercise combined with chemotherapy is more effective than exercise alone or chemotherapy alone. And what they've shown in these studies is that these primary tumors have a very poor vasculature. It's poor quality blood vessels, they're leaky and they're chaotic in there. But all these tumors, in order to grow, they need to draw blood vessels. They only grow to a very small size, and unless they get blood vessels within them, they can't grow any larger. So they all start developing these blood vessels. What they were able to show in these exercise studies is that exercise improves the quality of these blood vessels and the density of these blood vessels vessels. And while you're improving the quality of these blood vessels, what that improved was chemotherapy delivery to the tumor. So it improved the delivery of the drugs to the tumor. What it also does is improve perfusion to the tumor, and these tumors become better oxygenated. That's critical because radiation therapy is effective with, well, oxygenated tumors. If they are hypoxic to tumors, they're not radio sensitive. So now we start thinking, if you're exercising while getting radiation therapy or while getting chemotherapy, we might improve delivery of the drugs to the tumor and improvements in making them more radiosensitive. And we've seen this in actual human studies. So in actual studies with patients, we did a study in rectal cancer patients, and the treatment for them is a combination of chemo, radiation therapy, therapy prior to having the tumor surgically removed 12 weeks later. So they want to shrink and try and eliminate that tumor. And what we found is the patients who exercise while getting this chemo, radiation therapy were more likely to have a complete response, meaning the tumors were completely gone prior to having the surgery. So this is a very profound and important benefit of exercise, potentially to these patients who are getting treated with what we call neoadjuvant therapy, this kind of chemo and radiation therapy prior to surgery. So that's one very important mechanism and perhaps the most compelling. Once the tumor is surgically removed, you're no longer concerned about the primary tumor. You're concerned that a small number of cancer cells have been shed from the primary tumor and might spread spread throughout the body. So these cells have to go on an arduous journey through the vasculature so they can spread through the lymph system, but also through blood vessels. And there's some really interesting research suggesting that if you exercise while the tumors are shedding these circulating tumor cells, those circulating tumor cells are less likely to survive because of the increased shear stress. So when blood's flowing through the vasculature, it's under a certain amount of pressure. But of course, that's dramatically increased when you exercise. And these circulating tumor cells are far more likely to die. And not survive that journey if you're exercising. So this is another really interesting mechanisms for how exercise might be able to prevent the spread of a primary tumor. And once those cells are circulating or they've kind of disseminated elsewhere and in the body, this is where some of these other mechanisms can be important. The metabolic effects of exercise, such as reducing insulin and igf, these are all things that help cancer cells grow and divide more rapidly. The anti inflammatory effects of exercise can be very important. And probably one of the key ones is immune system tracking down and killing these cancer cells. Right. This is why we have the whole new treatment now, immune system immunotherapy. We've realized how important it is to call on the immune system to be able to track down and kill these cancer cells. So exercise in some ways was the original immunotherapy. You know, this was stimulating the immune system and improving natural killer cell cytotoxicity, the number of natural killer cells, the number of T cells and B cells that were all doing immuno surveillance of these cancer cells. So lots of good biological mechanisms for how exercise might improve these cancer outcomes.

Rhonda Patrick: That was phenomenal. Thank you for that explanation. A couple of follow up questions. So one, what you were just talking about the immune surveillance and I'm wondering. So I've read some studies about exercise and these are normal, healthy people and for a long time it was thought, thought like, oh, if you're sick, if you have a respiratory illness, you should not exercise. Because some studies that were done found that exercise acutely lowered the number of circulating T cells in the bloodstream in the vascular system. But then subsequent studies were done and found that actually those circulating T cells were going somewhere. They were actually going to the lungs. So they were immobilizing, going to the lungs to help fight off, you know, pathogens. Right. The respiratory, the causing the respiratory illness. Does exercise affect the immune cells like the cytotoxic T lymphocytes or the natural killer T cells immobilization to go to the site of the tumor as well as, you know, surveilling in the vascular system?

Kerry Courneya: Yeah, so that's been demonstrated in those preclinical mouse models. So they've shown that the mice that exercise will have higher numbers of T cells, natural killer cells within the tumor itself. So that improved blood flow allows everything to get into the tumor in order to be able to kill it. So yeah, the improved immunity, it will push all the immune cells out into the system to potentially track down some of these circulating or disseminating tumor cells, but it also increases immuno delivery to the actual primary tumor as well. Now, exercise, to your point, can be immunosuppressive as well, right? We know these very high levels of exercise, the kind of triathletes and the marathon runners, right. It can cause immunosuppression. And this was one of the reasons some oncologists early on were concerned about exercise. Right. These patients can become immunosuppressive from the chemotherapy treatments and other treatments. So they were a bit concerned with the very high intensity exercise in these patients. But most of what we're studying and looking at is more the moderate intensity or the higher intensity exercise, but for reasonable amounts of exercise, not sort of these marathon runners or these triathletes where you might overwhelm the patient.

Rhonda Patrick: And most people aren't out there running marathons. So it seems kind of silly to be so concerned about immunosuppression when a very small percentage of people are over training in that regard. Right. I mean, it's.

Kerry Courneya: Yeah, we don't have a public health concern about too many people exercising too much. It does happen. There is such a thing as exercise addiction and overdoing it and over training so on. But that is a very small slice of the population.

Rhonda Patrick: My second question is, you were talking about the shearing forces of, you know, increasing blood flow and that can kill these circulating tumor cells. There's a variety of ways you can increase blood flow through various forms of exercise. So, for example, aerobic exercise, it's on a continuum, right. With a higher the intensity you go, the stronger the sort of push of blood flow, you know, cleaning out the system, resistance training. So, so lifting, lifting weights can also cause blood blood pressure changes and changes in blood flow. Do you, do you think both of those types of exercise could affect that, that pathway? Or is it mostly the more higher intensity sort of aerobic exercise?

Kerry Courneya: Yeah. Based on the mechanism, then anything that increases that blood flow should work. So some of the research that's been done has been more of a pre clinical, in vitro model. So there's researchers who develop these plastic tubes, rubber kind of tubes, and they can spin blood through these tubes faster or slower, and then they can put these circulating tumor cells in these, this sort of microfluidic system that they've developed, and they can spin them around faster and slower. And they show that the faster you spin these around, consistent with what might happen during exercise, the more of these cells that die. So they've not looked at what's causing that Increase in blood, hemodynamic shear, stress. So, yeah, in theory, both strength training and aerobic exercise should. Should be able to do it. The one study that's been done in humans showing that exercise improves or reduces circulating tumor cells was an aerobic exercise program. But in theory, both should work.

Rhonda Patrick: And if you do reduce the number of circulating tumor cells in your vascular system, is that associated with. Is there data showing that is associated with lower, you know, cancer recurrence, lower cancer mortality, for example?

Kerry Courneya: That's right. So the way that cancer spread is these. It has to shed cells from the primary tumor, and they have to circulate throughout the blood vessels, and they have to get somewhere else. And so if you're preventing that or reducing that, you should be able to reduce the number of metastases. That's absolutely critical because that's what ultimately kills cancer patients. Right. So breast cancer, prostate cancer, you think of these cancers. The breast is not a vital organ. Women can live without a breast. So how do you die from breast cancer, prostate cancer? Men can live without a prostate. How do you die from prostate cancer? It's because these tumors shed these cells and they disseminate throughout the system, and then they arrive at places like the brain, the lungs, the liver, and the bone, and they set up what we call sort of colony tumors there, and they begin to grow and invade those organs. And that's how you ultimately die from breast cancer. If it's localized, you're not going to die from breast cancer. And so preventing that spread is really the critical aspect. And so reducing the number of circulating tumor cells is critical.

Rhonda Patrick: How long does cancer metastasis take? And does that vary by tumor type? So if someone's diagnosed with. Or let's say someone has stage one, they don't even know they have, say, what stage one. Breast cancer, prostate cancer, or colorectal cancer. What's the timeline typically like to get to the next stages?

Kerry Courneya: Yeah, and it varies dramatically by the types of cancer, for sure. So sometimes we see very small tumors might shed cancer cells. So even though we find what we think is a small tumor, it may have already shed these cancer cells, and they may have already spread. Sometimes the tumor can be fairly large and not have disseminated any tumor cells yet. And the real challenge there is these tumors can disseminate these tumor cells, and metastasis may not happen right away. Sometimes they sit dormant for years. So this is where someone with breast cancer may go in. We've got a primary tumor there. We cut it out. We don't know if any cells have disseminated. But five years later, eight years later, 10 years later, we detect a brain metastases or lung metastases. So these cells can sit dormant for an extended period of time before they sort of start to regrow. And so metastasis can be a very, very long process, or it can be a fairly short process. Other cancers, these cells spread quickly and they grow quite rapidly at these other metastatic sites.

Rhonda Patrick: Is there any type of tracking that can be done for tracking these types of. I mean, is it. Can you get a blood test and measure circulating tumor cells? Is that something that a test is sensitive enough to do?

Kerry Courneya: So that's the new area of hot research. So in the past, we could essentially only detect these cancers based on imaging. So these metastases would have to grow to a certain size, like 1 millimeter, 2 millimeters, before they would show up on these scans. So small numbers of cancer cells we couldn't detect. And so you're waiting many, many years, you know, doing a follow up scan five years later, and all of a sudden you see a spot on the lungs or a spot on the liver and say, okay, that could be cancer. So this whole idea of, can we find them earlier through blood tests, what they're calling liquid biopsies, and this is an area of a lot of research now where they're trying to develop these blood tests to detect small numbers of circulating tumor cells or small numbers of circulating tumor DNA, because these cancer cells will grow, divide, undergo cell death as well, and they'll shed some elements into the system. But this is very experimental. It's not being used in clinical practice practice right now. But there's a ton of research on these blood tests and liquid biopsies. So that would revolutionize cancer care. If we can actually go in at the time, you know, do a surgery, remove the tumor, and then test a few weeks later to say, are there any elements of circulating tumor cells still around, giving us an indication? Okay, well, maybe we need further treatments with chemotherapy or immunotherapy therapy. So it would revolutionize the field, but it's not in clinical practice yet.

Rhonda Patrick: Well, there are consumer available tests like grail that are available, these liquid biopsy tests that are done. Do you think, what are your thoughts on. On, like someone that's healthy without, like a family history, or perhaps with a family history of cancer, doing a liquid biopsy, like the grail test versus maybe like your. The situation that you're saying, which maybe it may be a little more applicable where someone has had a Cancer diagnosis has successfully, quote, quote, unquote, successfully undergone treatment in that the primary tumor seems to have gone away by all means and they go and do a grail test and perhaps maybe find something or don't find something, or maybe monitor, maybe someone does it yearly, annually, you know. I don't know. What are your thoughts on those tests?

Kerry Courneya: It's probably too early for the science, so you're talking about using it on sort of the prevention side of things or the early detection side of things, as opposed to the, the treatment recurrence side of things. Just reading a study today in colon cancer. They've got a blood test now out for colon cancer. They're comparing it to colonoscopy because that's the gold standard way we detect and it is fairly effective. It was like 80% sensitivity and 90% specificity, but they still were not recommending that for the general population. But I think it's coming down a pipeline. I mean, if it is available privately and you want to get that test done, you know, you want to check with your doctor in terms of how to interpret it and make sure you're looking at things properly. But I think that technology is coming down the road and it may not be too many more years when the average person is getting a blood test. On the early detection side of things.

Rhonda Patrick: On the cancer recurrence current side of it, let's say someone wants to pay out of pocket and they're going to go, do I say grail? Because that's like the biggest, probably most studied one that's out there for consumers. And let's say they find, oh, I have a positive test, I've got, you know, some, some tumor cell DNA that was detected and it's the same kind of cancer that I was previously diagnosed with. What would be the next step steps for someone? Do they go to the oncologist and then somehow verify? I mean, is there any way to verify if that's, you know, if the, if the test, you know, is accurate.

Kerry Courneya: Or so on the post diagnosis, the recurrent side of things. It is being used in clinical practice to some extent. So their oncologist may already be recommending that. So I would check with your oncologist to see if that is something that's recommended. The whole advantage, the idea of this is we have to be careful that we're not over treating cancer and of course we're not under treating cancer. So right now we over treat a lot of patients because we're not sure if they have any remaining disease. But we Just want to be sure. And so they get all these treatments that they ultimately didn't end up needing. So one of the advantages of this testing on the post treatment side of things is if there is no evidence of any circulating tumor cells, circulating tumor, tumor DNA, we can potentially de escalate the treatments and say you don't need any further treatments. Right now for the patient, that test is positive. We probably do want additional treatments if there's evidence that there's still small number of cancer cells around. So usually we'll recommend additional chemotherapy or immunotherapy, depending on what the doctors find. So yeah, check with your oncologist if that's already built into the clinical care or what, whether that's something that would be recommended.

Rhonda Patrick: Well, back to this exercise as insurance and the fact that, you know, aerobic exercise in particular, anything that's really increasing blood flow does seem to really have an effect on these circulating, you know, tumor cells. Then it would seem silly for someone who is, has been diagnosed, has been treated for cancer to not be, be just moving like their life depended on it. Right. Exercising as much as possible because it seems like that would be your best bet for reducing the cancer metastasis and ensuring that these circulating tumor cells do not go and take camp into another organ.

Kerry Courneya: Yeah, yeah. So again, we have a lot of research suggesting that it's still experimental, but I still think it is one of the few things the patients can do themselves. Right. Everything else is done to them, them done for them in terms of the chemotherapy, the surgery and so on. So patients are looking for what sorts of things can I do myself? And exercise probably has the strongest evidence of additional potential benefit beyond sort of their current treatments. So yeah, I think in some of these cancers we are going to be able to show that there's absolutely benefits to improved outcomes for these patients.

Rhonda Patrick: Are there? So you've done a lot of research on a variety of different types of cancer in control, conjunction with exercise and you know, standard care treatment. Prostate, breast, colorectal, on and on. So have you noticed that there are different types of exercise affect these different types of cancers differently in terms of combined treatment?

Kerry Courneya: Yeah, there are some differences among the cancers. So even though we use the term cancer like it's a singular disease, you know, it's a collection over over 100 different diseases and all the mutations that drive these cancers can be different. So not everything is going to be sensitive or receptive to an exercise intervention. But we see this with all treatments. Right. Some cancers are chemosensitive, some Are chemo resistant, some are radiosensive, some are radio resistant. We've even seen in immunotherapy that we make incredible gains with certain types of cancers. But in other cancers, immunotherapy doesn't seem to be effective at all. So we need to think this way about exercise. Exercise is not going to be a magic bullet for all these cancers. So it seems to help with certain cancers more so than others. And, you know, when you think on the prevention side of things, Their strongest association seems to be with colon cancer, so those cells might be particularly sensitive. Breast cancer has a strong association. Where some other cancers, we don't see much of an association like rectal cancer, prostate cancer, and stuff as well. So the different types of cancer, we might find cancers that are exercise resistant and cancers that are exercise sensitive, Depending on the types of mutations that are driving those cancers. But in addition to the types of cancers Affecting the type and benefits of excise, it's also really the treatments. What treatments the patient's on might determine what type of exercise is best, what amount of exercise is best. And to give you one example, We've really found a really good fit between weight training and a treatment for prostate cancer called androgen deprivation therapy. So men get diagnosed with prostate cancer, One of the main treatments is to eliminate their testosterone, because testosterone fuels the growth of prostate cancer. So they've given these drugs which take them down to castrate levels of testosterone. That's fantastic for the prostate cancer, but it's not very good for the man in terms of health, strength, muscle weakness, and these types of things. So these guys who are on these androgen deprivation therapies, We've done multiple studies with weight training, and that seems to be a really effective intervention for these guys to regain their strength, regain their muscle muscle and improvements in things like fatigue and energy. So again, depending on the types of treatment, certain, certain types and amounts of exercise may be more beneficial.

Rhonda Patrick: I wonder if it's interesting because compound lifts and lifting heavy is probably one of the strongest lifestyle factors that can increase testosterone. Actually, I'm wondering if it's having more of a local effect on muscle and not, you know, going to the prostate versus, you know, I guess, I guess other. Other things that would increase testosterone.

Kerry Courneya: Yeah, so that was one of the concerns of the clinicians when we first approached them about the patients. Oh, maybe exercise is going to increase the testosterone and help this prostate cancer grow. So a couple things. One, these drugs are so powerful, they take testosterone down to castrate levels. The small impact of excise the doctors are not worried that it's going to override that. But also those effects you're talking about tend to be just acute effects. The chronic effect can be a little bit of a reduction in testosterone, but it is one of the explanations for why exercise might increase, say prostate cancer risk. Some of the studies are mixed on that. Well, if it's driving testosterone levels, but in the context of cancer treatment, it would be very, very small compared to what these populations powerful drugs do.

Rhonda Patrick: Well, I'd love to kind of on the flip side of that, talk about exercise as a monotherapy. So there's been some pretty recent large scale trials that you're involved in a race, the prevent trial, that are potentially going to be looking at exercise, you know, exercise as a monotherapy in, you know, low grade early stage cancer. This is an area that really excites me. So I'd love to hear a little bit more about that.

Kerry Courneya: Yeah. So as I mentioned, you know, most cancers get treated with a combination of treatments that we give in different combinations in different sequences. So these patients are very heavily treated. When we think about exercise as a monotherapy, we think about exercise by itself. What's the effects of exercise by itself on cancer? So we've done the pre clinical studies in mice. We can take these mice, we can inject small number of cancer cells or implant small cancer tumors and we can randomly assign them to exercise versus no exercise, just like the drug researchers would do. Drug versus not. And we can show in those studies that exercise by itself, independent of any other treatments, tends to slow the growth and spread of these cancers. Most of the studies are showing that, not all, but most of the studies. So then you think of clinical scenarios, well, if all these patients are getting treated, what's the relevance of that clinical scenario? But there's a new clinical scenario in cancer. And as I mentioned before, there's concern that some of these small, low grade cancers, maybe we're over treating them, maybe we're jumping in and treating these patients, causing all sorts of side effects, not to mention the medical costs and so on. Maybe they don't need to be treated. And this whole approach to managing cancer is now called active surveillance. So these cancers are so small and so low grade, slow growing, that we're not going to jump in and treat these cancers with anything. It's being used mostly right now in prostate cancer. That's where they've pioneered this active surveillance. But it's starting to get attention even in other cancers about maybe, maybe some of these cancers we don't need to jump in and treat right away. So now you've got these guys diagnosed with prostate cancer and they're not giving any treatments whatsoever. So this has allowed lifestyle researchers to kind of jump in and say, what's the role of lifestyle here? Can we help these guys out at all? So we've done a recent study looking at high intensity interval training in these men with prostate cancer who are on active surveillance. No other treatments. In addition to improvements in fitness and function and the types of things you might expect, we also showed that this high intensity exercise lowered prostate specific antigen levels, PSA levels. So this is how men are sometimes screened for prostate cancer. Looking at PSA levels can be an indication of how much cancer there is in the prostate. So we showed that this high intensity exercise lowered PSA levels. And then we also looked at these prostate cancer cells in a petri dish, just an in vitro model where we exposed those prostate cancer cells to the serum of the men who exercised or the serum of the men who didn't exercise. And we showed that exposing them to the serum in the men who exercise reduced the growth of those prostate cancer cells, suggesting that there's something that exercise is doing and we think it's the anti inflammatory, the insulin act, IGF immune system effects that are slowing the growth of these prostate cancer cells. So this is a very exciting area because many of these guys who are on active surveillance ultimately will require treatments. So if you can delay the need for treatments or prevent treatments, you can substantially improve their quality of life. So very promising exercise intervention in that clinical setting.

Rhonda Patrick: Why did you choose high intensity interval training as your exercise intervention type versus something perhaps more moderate intensity like jogging? Is there something about HIIT and vigorous exercise that you felt was maybe more beneficial for, for, for the, for the prostate cancer or is it just easier to adopt that type of routine for people?

Kerry Courneya: I think it's the evidence suggesting that high intensity activate activates more of these biological changes. So I think of it kind of as stirring the biological soup, right? The body's got all these biological processes and the more intense the exercise, more, more these biological changes get stirred up. So you're going to send more immune cells into the peripheral blood, more of the changes in insulin and igf, more of the anti inflammatory markers. So there seems to be a dose intensity effect on some of these biological changes. And because we're targeting biological changes as opposed to functional changes, we want to go with what we think is the optimal exercise prescription for really driving biological changes that might be relevant for cancer growth.

Rhonda Patrick: So how do you guys, and maybe in this trial or generally speaking, take someone who's under active surveillance? Maybe they, they have been sedentary. They're not someone that's really done structured exercise, you know, as a routine and help transform their fear. Because I'm sure it's scary to be diagnosed with prostate cancer as early or as, you know, I would say, you know, low grade as it is, it's still probably a very scary, fearful process. Are there any sorts of programs, structured program programs that can help, like having a coach or group classes, things like that? That. What, what would help for someone in that situation? What did you guys use in the study?

Kerry Courneya: Yeah, so many of these guys are quite motivated to do something for themselves. So that's one of the big motivating factors, right? Waiting around just for treatments or just getting the surveillance, which is, you know, regular PSA screenings and, and biopsies and those types of things. So many of these patients, cancer diagnosis can be a bit of a wake up call. It can be a bit of a teachable moment in the sense that, oh, you know, I am not immortal, maybe I do need to take care of my health. So oftentimes it prompts patients to say, what can I be doing to try to improve my health? So some of it is just the experience of a chronic disease can be very scary. And thinking about taking your health more seriously than you might have done when you're focused on the prevention side of things. So we motivate those guys by talking about the cancer specific benefits. As I say, if it's just improvements in fitness, just improvements in strength, yeah, these are the standard benefits that everybody gets. But what about me, right? And cancer patients are very concerned about their cancer. Once you're diagnosed with breast cancer or liver cancer or brain cancer, you become focused. Focused on what? What kind of diet should I eat for someone with brain cancer? What kind of exercise should I do with brain? You're not interested in general health benefits. So they want to know about these cancer specific benefits. And so we'll usually talk about those types of benefits to try and motivate them, say, hey, this might actually help with your cancer. It might help with your treatments, getting through the treatments, recovering from treatments. And of course, we always work with them where they're at. We tell them, you know, we'll never ask you to do more exercise than you can do. We'll progress you slowly, we'll build you up to the prescription. One of the other key things for cancer patients is the opinion of the oncologist the oncologist is absolutely crucial. You know, if they, if the oncologist says that that patient should be exercising or think about exercising, they take that very seriously. So we've been able to get these oncologists on board or the urologist and say, hey, your urologist thinks with your prostate cancer that you should be exercising as well. So it's really building that team of support and motivating patients with the benefits that are going to be specific to them and their unique situation with the.

Rhonda Patrick: Oncologists and getting them on board. Is that something, you know, you often do still hear? Again, even oncologists will say to take it easy, to rest, especially if they're gonna undergo, you know, they're not in active surveillance, but perhaps they're gonna undergo a treatment like a chemotherapy treatment or radiation. And so how do you sort of change the, you know, the paradigm here and help perhaps a patient give the right information to their oncologist, like giving them studies or what can help sort of change the oncologist from a, you should rest and take it easy or just a light walk around the neighborhood to okay, we should do some high intensity interval training classes to help with treatment.

Kerry Courneya: So the short, simple answer is evidence. So oncologists will recommend for patients things that are evidence based. And one, I think the real strength of the exercise oncology field is we've subjective exercise to the same rigorous research that they would subject their drugs to. So we do randomized controlled trials, which are sort of the gold standard research methodology with large sample sizes showing these benefits for their patients. And then we publish them in the top cancer journals that the oncologists read. So that's what they're looking for is evidence, not that anecdotal stories about, hey, my uncle Fred did this and his cancer went away. They want to see these high quality research studies. And so that's been building over the last couple of decades, slowly at first, but now much more quickly where the evidence is getting out there. And most oncologists are now aware of it in fact, two years ago, so it's only in 2022. Two years ago, the American society of clinical oncology put out its first exercise guidelines. So this is cancer doctors. So it's one thing for exercise specialists to say, hey, cancer patients should exercise, but now we have the cancer doctors themselves, their professional organization, asco, the American Society of Clinical oncology, says all cancer patients who are being treated with curative intent should be recommended aerobic and resistance exercise. Well, while they go through treatments. And those guidelines are adhered to very closely by oncologists. So they, almost all of them now will be aware of these new ASCO guidelines saying you need to be recommending and referring your patients to a good quality exercise program to help them get through treatments.

Rhonda Patrick: Well, that's really good news to hear. I want to kind of circle back to something you mentioned earlier with respect to the benefits of exercise along with treatment in cancer patients on psychological health. And maybe you can talk a little bit about how important these benefits are compared to maybe some of the anti cancer benefits or perhaps even you have. One of the big takeaways from the ERASE trial was that exercise seemed to reduce the fear of progression and along with fear and that the stress you get stress hormones and stress hormones really can help fuel tumor growth as well. So maybe you can sort of talk about the psychological benefits and sort of. Are they uncoupled from the anti cancer benefits?

Kerry Courneya: Yeah. So in one way, it's one of the surprising, I think, findings in this literature. When we talk to some of our patients, they will tell us that the psychological benefits are more important to them than even what it's doing to the cancer or some of these other outcomes because it can be very difficult to cope with cancer psychologically. As I mentioned, cancer patients will say everything about cancer is not normal. And when they exercise, they start to feel like they have some control over the cancer and that their normal life. I'm out playing tennis or I'm out golfing, I feel like I'm normal again. So these psychological benefits can be things like improved self confidence, improved self esteem, certainly managing the anxiety associated with cancer. And you mentioned the finding related to fear of cancer progression or fear of cancer recurrence. This is a huge issue in cancer patients. You can imagine being diagnosed with cancer. You go through the different treatments. At the end of the treatments, we tell the patient there's no evidence of disease. We've done the scans, we've done the various other tests. We think it's gone. How will we know it's gone? Well, we're going to follow up every six months and we're going to do these tests and then we're going to tell you whether the cancer's come back. So we can't tell you definitively at the end of treatment that your cancer is gone. Go back to your normal life. We know these recurrences happen. And now you can imagine every six months the anxiety and stress of going in and getting these imaging cancer tests and blood tests. And then meeting with your oncologist who's going to say the cancer's back or it's not. And patients will tell you that finding out they've had a recurrence of the cancer is even more devastating than the initial diagnosis of the cancer. So this fear of cancer recurrence can paralyze these patients as they continually go through this surveillance. And at no point can we ever tell them that the cancer is definitively gone. In some cancers, there's recurrences 10, 15, 20 years later. So this is very stressful. So the impact we showed in this study of excise, helping them manage that fear of cancer progression or fear of cancer recurrence, really important, helping them get on with their daily lives. To say I have to live my life with cancer in the background, even though, you know, I have this psychological stress. So, yeah, those psychological benefits, I think are really important for these patients. In addition to some of the functional benefits and the disease related benefits and controlling the side effects, there's been some.

Rhonda Patrick: Pretty large randomized controlled trials over the years and even meta analyses of these randomized control trials comparing exercise, whether it is aerobic, a lot of times running or cycling, even resistance training has been thrown into the mix. Comparing them to standard of care treatments for major depressive disorder like SSRIs. Right. And exercise as a treatment, it seems to work just as good, if not better than a lot of these SSRI drugs are working for, for the treatment of depression, which is amazing because then you're going to get all the cardiovascular benefits, the muscular benefits met metabolic benefits. Right. Like the endless benefits of exercise in addition to the mood benefits. Right. So it's not that surprising to me that exercise would have a very positive effect on, you know, on mental health of cancer patients, on reducing anxiety and fear. Because it's been shown in, you know, outside of the cancer context and other sorts of disease that are affecting the brain and mental health as well. And also you mentioned something interesting. You said that exercise seems to help cancer patients feel they have control of their lives. Right. Because I could imagine a cancer diagnosis does feel like you lose complete control of your life. I mean, it's like, it's very scary. And so I wonder also just if there's almost a placebo effect. Placebo effect is a real biological phenomenon, as you know. And I mean, changes in immune system, dopamine, A lot of things are happening when you have a positive outlook, when you feel like you have control of something. And so you almost wonder if that spills over to some of these psychological effects helping the anti cancer effects as well. Like there's probably some crossover there.

Kerry Courneya: Yeah, I think that's definitely part of the explanation is some of these benefits. But as you know, there's good biological effects as well on deposits, depression, on neurotransmitters, these types of things. So there's a biological basis for some of these improvements in things like anxiety and depression. But some of these other improvements, things like self esteem, is just patients feeling better about themselves because they're doing something that they believe is helping themselves. So these are all important psychological changes. And the big difference, you know, we look at all those literatures outside of cancer related to depression and cognitive function and anxiety and so on, but in patients, you know, you're dealing with depression based on a cancer diagnosis and depression based on treatments and stuff. So what we've been able to show is exercise helps with the anxiety, the depression and the stress associated with a cancer diagnosis and treatments and side effects that we weren't sure they were going to help with. So it really helps manage some of that psychological stress caused by the cancer and its treatments.

Rhonda Patrick: Well, it sounds to me like the bottom line is, I mean, at every stage, exercise is something that people need to absolutely focus on for cancer prevention, for cancer treatment and continuing treatment. So, you know, not only is helping you get through the treatment, perhaps you know, even having beneficial outcomes, you know, with reducing mortality risk, reducing cancer recurrence, but that psychological, let's say you, okay, you get through the treatment, you got rid of the cancer, okay, it's gone. And some people might think, okay, end there, I'm done. But the reality is then you do have to keep going back for these screenings. You do have to worry about a few of those tumor cells that escaped and maybe are going to continue growing at this tumor site or somewhere else. And so having exercise as a part of your daily routine, routine is going to make everything easier and it's going to improve the chances that you are not going to have cancer recurrence. So there's every reason to exercise and every, you know, there's every reason to be motivated to exercise.

Kerry Courneya: Yeah, we think about it, exercise having benefits across the continuum of cancer care. So from the time of diagnosis and for the balance of life, so the initial diagnosis, helping you prepare for treatments, once you start treatment, help you get through those treatments and complete those treatments afterwards, we're looking at recovery from those treatments and then after treatments, when you're in what we call the survivorship phase, reducing the risk of recurrence but also reducing the risk for other chronic diseases. So unfortunately, many of the treatments that cancer patients get increase the risk for cardiovascular disease. Some of these drugs are cardiotoxic, increase the risk of osteoporosis, they increase the risk of diabetes. So now you've kind of survived your cancer, but now you're trying to prevent some of these secondary diseases that might occur. So there's lots of good reasons to exercise right across the cancer trajectory.

Rhonda Patrick: Before, before I move on to just a couple of rapid fire questions, is there anything that we didn't cover, perhaps that might be important to discuss?

Kerry Courneya: I think you've covered, I mean, the other way I think about exercise in terms of its importance when you look at what's currently being done for cancer patients, because a lot is being done. So they're offered a lot of other complementary therapies, Art therapy, music therapy, acupuncture, massage therapy, psychological counseling, stress management, and these are all having benefits on symptoms, side effects, quality of life, just like exercise. But none of those other interventions have shown any benefits for survival, any benefits for the disease itself or risk of recurrence. And then you look at the treatments we give for cancer like chemotherapy, radiation therapy, all those interventions benefit the survival side of things, but they oftentimes undermine quality of life. They make symptoms and side effects worse. Exercise is one of these few interventions potentially for patients that can help both with quality of life, side effect symptoms and also improve disease free survival. So it's a real win win compared to many of these other interventions that we offer cancer patients.

Rhonda Patrick: Do you have any idea what percentage of people that are diagnosed with cancer actually do use exercise in conjunction with their, with their treatment?

Kerry Courneya: Yeah, we've done a lot of those surveys and what we show is just to give you the pattern of it, we asked many of these long term survivors what they were doing before diagnosis, what they were doing during treatment and what they were doing after treatment. And what all this research shows is that a cancer diagnosis and treatment has a very negative impact on exercise levels. All of these patients report doing dramatically less exercise during treatment than they were doing before diagnosis. After treatments and survivorship, exercise will tend to increase back, but not back to pre diagnosis levels. So it's like the diagnosis and treatment of cancer is kind of having a permanent negative impact on exercise levels. So what this tells me is that if we don't intervene, we're not helping patients exercise. If we oncologists and cancer centers aren't working with patients, the natural response of anyone diagnosed with cancer Is to sort of give up exercise, get through these treatments, and try and recover afterwards. So this is why interventions and support in cancer centers from the American cancer society are all very important. And when we ask during treatments, in some of our studies, no more than 5 to 10% of patients remember meeting the exercise guidelines during treatments. Pumps up to 30 to 40% after treatment. So again, there's some sort of recovery afterwards there, but they're still lower levels. When we compare cancer survivors with the general population, it's not much of a difference overall in terms of the physical activity levels. They're similar between the general population and cancer survivors, but it varies, as you can imagine, by cancer type, cancer stage. So some cancers like breast and prostate and colon, the exercise levels are reasonable. But some of the more difficult cancers like brain cancer, liver cancer, pancreatic cancer, the exercise levels are much lower. And of course, for the stage 4 metastatic disease, again, we see that having a very negative impact on exercise levels. So there's lots of variation. But cancer in general, and treatments in general will take, tend to have a negative impact on patients exercise levels. And they need that support to be able to exercise right after diagnosis.

Rhonda Patrick: Well, how do they get that support? And also, what about people that are sedentary before a diagnosis who aren't even used to working out or exercising, and then now they're facing a cancer diagnosis and they should be exercising? Like, how do we get those numbers up?

Kerry Courneya: Yeah, great question, and you're right. So. So the patients that we work with who exercise before diagnosis, they believe in the benefits of exercise. They're aware of the benefits of exercise. It's not hard to convince them to try and exercise during treatment once you explain it to them. For patients who have never exercised, you know, walking in as they're about to start chemotherapy and talk about exercise doesn't seem like a good time to start exercise when you've not been exercising all your life. So again, this is where the support of the oncologist, the oncology nurses, and the whole cancer care team are really important to say exercise isn't an add on. You know, it's a critical part of your cancer care. It's really going to help you with these treatments. So some of it's just the education and the awareness of the, of the role of exercise in these newly diagnosed patients and also letting them know we can start with something that's realistic and feasible for them. I mean, some of them are scared because they think exercise is lifting heavy weights and high intensity exercise, and they're about to start chemo and letting them know that starting even with walking program can be very beneficial. And then we're seeing a big growth in community based exercise programs for cancer survivors. We have Livestrong at the ymca, which is a program being rolled out across the US where you can go and work with an exercise specialist, specifically working with cancer survivors. And many of these cancer centers have fantastic exercise programs. MD Anderson Cancer center in Houston, Memorial Sloan Kettering in New York, Dana Farber in Boston. A lot of the top cancer treatment centers now have exercise specialists working right at the cancer treatment center, offering these programs to patients who are newly diagnosed. So there's a bunch of things that are going on to try and, and help patients. You know, their big concern in the US Is the coverage. You know, these be paid for by the health insurance companies. And many of these major cancer centers across the US you see a lot of support from philanthropic dollars. So donors who believe in the importance of exercise say, hey, I want to fund an exercise program because I see this as being really important for these patients. So we have to think how about how we can fund it, how we can, can deliver it, and make sure that all newly diagnosed cancer patients have access to these exercise programs.

Rhonda Patrick: I don't know how the cost of chemotherapy seems like it'd be much more than the cost of an exercise program. Obviously we're not talking about exercise as a monotherapy for every cancer type and every diagnosis because some people are advanced. But it seems like a drop in the pool when you're comparing it to the cost of, of a lot of these treatments.

Kerry Courneya: These chemotherapies can be very expensive. These newer immunotherapies can be very expensive. And this is where if we can demonstrate exercise as a benefit for any of these cancer outcomes, it would be game changing. I remember a study we did where we showed that breast cancer patients who exercised during chemo had a lower risk of recurrence or dying from breast cancer eight years later. I remember talking to the medical oncologist and says, if we can demonstrate in a larger study that exercise lowers the risk of recurrence, he said that would change the game. He says, you know what it costs when a breast cancer patient has a recurrence? A million dollars. So that's the estimate that the health care system is going to be in for when someone has a recurrence of cancer with all the drugs and treatments and all the medical care that they're going to be entitled to receive. So you're right, you know, even if we can prevent a small number of recurrences. The cost effectiveness of excise is very high. Very recent study in breast cancer patients with metastatic cancer, wonderful randomized control trial showing many of these benefits we talked about Also did the cost effectiveness analysis and showed this is a very cost effective intervention as well, compared, as you've pointed out, to many of these other treatments that we're offering patients.

Rhonda Patrick: But these exercise treatments have been shown to lower recurrence. Is it just not a large enough study or more studies are needed to convince?

Kerry Courneya: So most of the stuff linking exercise to lower risk of recurrence has been observational studies, epidemiological studies. So these are always viewed with a healthy amount of skepticism by oncologists and by health insurance companies and stuff as well. Oh, there's an association between exercise and these cancer outcomes. And some of the randomized controlled trials that have been done have been very small studies. 50 patients, 60 patients. So we're in the process of conducting some of these larger randomized controlled trials that would be equivalent to a drug trial. You know, if you were testing a new chemotherapy, a new immunotherapy, sometimes they're randomizing 500, 1,000 or more patients. So some of those trials are going on right now in the exercise field. And those will be viewed as the definitive trials one way or the other, showing whether or not exercise can improve these cancer outcomes.

Rhonda Patrick: I'm assuming that using biomarkers like reducing circulating tumor cells, which would ultimately affect cancer recurrence, isn't enough to convince.

Kerry Courneya: This is a big debate in the oncology field, Let alone the exercise oncology field. Yeah, we call these surrogate endpoints, you know, and are these going to be acceptable? And there's a big debate whether or not, you know, drugs should be approved based on some of these intermediate or surrogate endpoints. So of course, as exercise oncology researchers, we just follow along what is acceptable within the what would it take to get a drug approved would be the similar outcomes we look at. So in some of these ongoing trials, we're looking at disease free survival, which is a well accepted endpoint. We're looking at a pathologic complete response to the intervention, which is another accepted one. Whether or not circulating tumor cells or circulating tumor DNA might become an accepted endpoint demonstrating a clinical benefit. We'll see where that goes.

Rhonda Patrick: Well, the good news is that there are many ways to exercise that are free than you can do at home, you can do in your neighborhood at a park. Right. So, yeah, it is nice to have that Support of a group class. And it's certainly very beneficial to have a coach, a class, I think. But at the end of the day, if you're looking at affecting your mortality, your recurrence, your mental health, your, all the things that you discuss, then you know someone's going to be motivated to go, go out and do it.

Kerry Courneya: Yeah.

Rhonda Patrick: So. Okay, so I have a few rapid fire questions. I would say if you, if there were only one sentence you could permanently tattoo onto every patient's mind about exercise, what would it be?

Kerry Courneya: Don't take cancer lying down. That's what we started with. That would be the, the take home message for patients.

Rhonda Patrick: It's a great one. What's a myth about exercise or cancer that drives you crazy?

Kerry Courneya: Okay, you might not like this myth, but the myth is that exercise improves everything. Exercise makes everything better, improves all outcomes. We've seen in the exercise oncology field, we didn't get a chance to discuss it, but there's a few preclinical animal models showing that exercise makes some tumors grow more quickly. So, so it's not this panacea for every single tumor. In general, it slows the growth and spread. But we've seen a few publications showing the mice that exercise, the tumors grow more quickly. We've also seen a few studies, including a couple of my own, showing exercise exacerbating symptoms in cancer patients. So in one of our studies in rectal cancer patients, it looks like the exercise intervention made skin irritation from radiation worse. Exercise making skin irritation worse. It looks like it made diarrhea worse in these patients. Hand foot syndrome, which is sort of appealing. And tenderness in the feet and hands. You can imagine walking on a treadmill or lifting weights. And in a couple studies it's shown it's made fatigue worse. So there are these, you know, we have to be very careful about. Exercise will benefit everything, cure everything and make, make everything better. And I'll end off. There is one cancer. We talked about prevention, that exercise increases the risk of cancer. And I suspect you can probably guess it.

Rhonda Patrick: Which one?

Kerry Courneya: Skin cancer.

Rhonda Patrick: Oh, because you're outside.

Kerry Courneya: Yeah. Not having something so very compelling.

Rhonda Patrick: But it's not exercise that's doing. It's sun exposure.

Kerry Courneya: Correct.

Rhonda Patrick: So that's, that's a bit misleading.

Kerry Courneya: So. Well, well, it's, it's misleading one sense. Yeah. But pain patients who regular exercise have higher rates of skin cancer than non exercisers. It's due to this exposure. So the American Cancer Society is always reminding, wear the, you know, the sunscreen and stuff when you go out and cover up during exercise as well, because you are potentially putting yourself at higher risk of skin cancer. So we just have to be careful about making sure we're giving good evidence on what the benefits are for patients and understanding some of the harms. And we don't necessarily track all the harms of exercise in these studies, but we now are doing that. What are some of the adverse events? What are some of the issues that might be caused by exercise? Having said that, the benefits of exercise far outweigh the harms of exercise. But so we don't have to sort of put the harms under the rug, you know, to make the case for exercise. We want to track those, we want to make sure they're clear. But what we demonstrated in cancer is the same thing. The benefits of exercise for these patients far outweigh any risks to harms. And we do have to be careful about exacerbating symptoms, making sure patients are exercising within their own capacity. The other thing I forgot to mention is the risk with bone metastases. That's a big concern in the exercise field. So one of the most popular places for, for cancer to spread is to the bone and these bones can become a bit more brittle. So the risk of fracture in patients with metastatic bone disease, and again, we just have to work around that with the exercise prescription. But that's a risk we have to.

Rhonda Patrick: Be aware of with the animal, the preclinical animal models. What types of tumors were exacerbated by exercise?

Kerry Courneya: It's a great question. And the problem is we haven't sorted that out. So there's no sort of pattern yet to be, okay, it's exacerbating, you know, pancreatic cells, but not liver cancer cells. Or that it's the high intensity exercise making things worse or versus low intensity. Or when we look at cancer with this type of mutations, or if we do forced exercise versus voluntary exercise. So people have looked at all that to try and sort out these studies. It's about 10% of the studies. So the majority show exercise slows the growth and spread. About 10% are showing this tumor is growing more quickly, but there's no pattern to it that we can say, ah, we think this is what's, what's driving it.

Rhonda Patrick: So it's not like they're being, the animals are being injected with a certain type of tumor. It can't be traced to that type of tumor. Maybe it's the background of the mice.

Kerry Courneya: Exactly. All those factors are kind of being looked at, but there's no pattern yet that would suggest it. So it's just something to be aware of as we, as we do these types of studies.

Rhonda Patrick: Okay, next question. Have you ever encountered a case where effortful training didn't help? And what did you learn? I think you just answered that.

Kerry Courneya: Exactly. So that's, I think one of the key things is this exacerbation of symptoms. We have to work around the side effects and the symptoms that patients are experiencing to make sure the exercise is safe and tolerable for them. So, you know, if patients are experiencing peripheral neuropathy, some patients experience issues with ataxia, balance and stuff as well. So, you know, we're putting patients on treadmills. We have to be careful that they're going to be able to do that type of exercise. And then side effects, like I say, like diarrhea, skinnier retirement, irritation. You know, we get into cancers like rectal cancer and anal cancer. That whole area down there gets radiated. They get radiation burns and movements with clothing and stuff can, can be, patients can get dry mouth and stuff from, from exercise and, and it can lead to increases in diarrhea and stuff as well. So we're just working with the patients with other symptoms they're experiencing and making sure that we're not exacerbating those symptoms.

Rhonda Patrick: Yeah, sweat. I mean, if you're sweating a lot, you can also exacerbate skin problems. And I do think at the end of the day, like, is there a trade off? Like, is the skin irritation or the little bit of diarrhea the price you pay for, like, even more, you know, positive benefits? And so that's also probably something you consider as well and discuss with the patient where it's like, you don't want them to necessarily stop the treatment because they have a little skin irritation. But, you know, it's, again, it's. I mean, I guess it's my mentality of thinking too. I'm very much like, I'll handle like some suffering if it's going to have a net positive effect.

Kerry Courneya: That's right. Yep.

Rhonda Patrick: What's one habit or purchase under $50 that can help patients stay active at home during tough treatment phases?

Kerry Courneya: I guess probably one of these activity trackers or fitness trackers might be very helpful. And there's a lot of research right now trying to develop mobile apps for exercise and cancer survivors. One of my own PhD students looking at a mobile app and seeing whether or not it might be helpful for breast cancer survivors. So we'll see. I think some of these technological things that might be available to help cancer survivors get regular exercise.

Rhonda Patrick: If someone only has 15 minutes a day, what's the single best use of that time to fight cancer? If it's exercise, then what type?

Kerry Courneya: I'd probably go with the strength training and probably go, you know, with, with some of the heavier lifting, strength training, the squats and the compound exercise you've talked about. You know, I think what we're seeing is this idea of lean muscle mass, skeletal muscle mass being extremely important for getting through these treatments, predicting recurrence, predicting survival, strong associations with physical functioning and quality of life life. So I think targeting the muscle mass, if you've only got 15 minutes, that's probably how I would spend my time.

Rhonda Patrick: Nice. I do CrossFit training and it's an hour long session I'll do. And there's a lot of strength training at the beginning, progressively working up heavier weights and different types of compound lifts. But typically at the end of the workout it'll be like a 15 or 20 minute workout. And it incorporated, you know, these, what you're basically saying, you know, squats or deadlifts or these types of strength training and resistance training exercises that do increase heart rate, that are improving muscle mass, improving strength, improving function, but then it incorporates like some rowing or biking along with it. So you're getting like a high intensity interval training workout that's including resistance training. It's very dynamic and I think it's very time efficient and I think it's wonderful, a wonderful time of training. Plus you can get a group, go to group CrossFit classes and have that group setting as well where you're getting that reinforcement from other people when coach is there. Well, thank you so much, Carrie, for all of the research that you're doing. Very, very important research. And for anyone that's wanting to continue to read some of your publications, they can obviously look you up on PubMed. But also you've got a faculty page at the University of Alberta, Canada. People can go to that faculty page and find your faculty page there to look up some of your research as well.

Kerry Courneya: Yeah, and the American Cancer Society is a great resource as well. They've got a lot of information on exercise for patients and survivors.

Rhonda Patrick: Well, thank you so much for joining me today. Really enjoy this conversation and appreciate everything that you do.

Kerry Courneya: My pleasure. Thank you for having me.