HIIT suppresses colon cancer cell growth.
Just a single session of HIIT – high-intensity interval training – reduced the number of colon cancer cells in vitro, a 2019 study found. Researchers attributed the cancer-suppressing effect of HIIT to a transient increase in inflammatory cytokines that occurred shortly after the exercise.
The study involved 20 male colon cancer survivors. Half of the men performed a single, 38-minute bout of HIIT (at 85 to 95 percent of their maximum heart rate), while the other half performed 12 HIIT sessions over a period of four weeks. Researchers treated cultured colon cancer cells with serum taken from the participants at various time points before and up to seven days after their respective HIIT protocols.
They found that serum collected immediately after engaging in HIIT reduced colon cancer cell numbers in the cultured cells. HIIT also produced increases in pro-inflammatory cytokines interleukin (IL)-6, IL-8, and tumor necrosis factor. Interestingly, the inhibition of cancer growth was transient, lasting less than two hours post-exercise when inflammatory cytokine levels were high. The serum collected at other time points had no effect on the cancer cells' growth.
The pro-inflammatory response that normally results from exercise peaks roughly an hour post-exercise. It then begins to subside and is followed by a powerful anti-inflammatory response – an essential process for maintaining an appropriate balance of pro- and anti-inflammatory mediators.
These findings suggest that transient exercise-induced inflammation slows colon cancer growth, potentially influencing cancer survival. Sauna use mimics many of the physiological effects of exercise and may be suitable for cancer survivors with health or mobility issues that make exercising difficult. Learn more about sauna use in our overview article.