Aerobic exercise – especially high-intensity exercise – reduces symptoms of anxiety, an analysis of 15 studies shows. These anti-anxiety effects endured for several months after cessation of the exercise.

Reviewers analyzed data from 15 studies that investigated the effects of low- or high-intensity exercise on anxiety symptoms. All the participants in the studies had some degree of anxiety, with their conditions falling on a spectrum that included anxiety disorders, raised anxiety levels, and raised anxiety sensitivity – a condition in which a person feels anxious about the physical symptoms that often accompany anxiety. People on waiting lists for anxiety treatment who did not exercise served as comparisons.

They found that participants who engaged in both low- and high-intensity aerobic exercise experienced greater improvements in their anxiety than non-exercising people on treatment waiting lists. High-intensity exercise reduced anxiety symptoms more effectively than low-intensity exercise. The various interventions lasted between 10 weeks and six months, with participants exercising three times a week, on average.

Multiple mechanisms may be responsible for the anti-anxiety effects of exercise. For example, high-intensity exercise promotes the production of lactate, a byproduct of glucose metabolism that participates in the production of neurotransmitters, such as norepinephrine and serotonin. Low norepinephrine and serotonin levels can drive anxiety and the inability to handle stressful situations. Learn more about lactate and its effects on the brain in this episode featuring Dr. George Brooks.

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