Clinical Trial Finds Exercise Reduces Long-Term Stress Hormone Levels

Year-long study shows aerobic activity can lower cortisol, a key biomarker of stress

Apr. 18, 2026 at 1:36am

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A translucent, ghostly X-ray image showing the intricate structures of the heart and lungs, glowing with a soft blue light against a dark background, conceptually representing the biological benefits of aerobic activity on the body's stress response.An X-ray view of the body's internal structures reveals the stress-reducing power of regular exercise.Today in Pittsburgh

In a groundbreaking clinical trial, researchers found that adults who engaged in 150 minutes of moderate-to-vigorous aerobic exercise per week for a year experienced significant reductions in their long-term cortisol levels compared to a control group. Cortisol is the body's main stress hormone and high levels are linked to various health issues. The study, led by researchers from the University of Pittsburgh and AdventHealth Research Institute, is the first of its kind to examine the long-term effects of exercise on stress biology.

Why it matters

The findings suggest that regular physical activity, as recommended by health guidelines, may be an effective behavioral strategy to mitigate the adverse effects of chronic stress and improve overall health and well-being. Most prior research on this topic has been correlational, so this clinical trial provides important causal evidence on the stress-busting benefits of exercise.

The details

The study included 130 adults aged 26 to 58 years old, who were split into two groups. One group engaged in 150 minutes of moderate-to-vigorous aerobic activity every week for a year, while the other group received general health information but did not change their physical activity levels. Researchers monitored changes in cardiorespiratory fitness, cortisol, and other measures of stress and emotion using advanced techniques like brain imaging.

  • The clinical trial was published online in the Journal of Sport and Health Science on March 17, 2026.
  • The study was conducted over the course of one year.

The players

Dr. Peter J. Gianaros

Director of the Center for Mind-Body Science and Health and faculty at the University of Pittsburgh.

Dr. Kirk I. Erickson

Director of Translational Neuroscience and the Mardian J. Blair Endowed Chair of Neuroscience at the AdventHealth Research Institute.

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What they’re saying

“The effect of exercise on long-term cortisol levels could be one of the mechanisms or benefits of exercise that protect against several diseases and some mental health conditions, but more research is needed to fully explore this possibility.”

— Dr. Peter J. Gianaros, Director of the Center for Mind-Body Science and Health

What’s next

The researchers hope these findings will draw more attention to the mental resilience and overall health benefits of meeting the recommended goal of 150 minutes of physical activity per week. Further research is planned to explore the mechanisms by which exercise may influence stress biology and brain aging.

The takeaway

This landmark clinical trial provides strong evidence that regular aerobic exercise can significantly reduce long-term levels of cortisol, the body's key stress hormone. These findings suggest exercise may be an effective behavioral strategy to mitigate the adverse effects of chronic stress and improve overall health.