In the first clinical trial of its kind, published online in the Journal of Sport and Health Science on March 17, 2026, researchers conducted a one-year randomized clinical trial to examine the long-term effects of aerobic exercise on the biology of stress and emotion. The study was led by Dr. Peter J. Gianaros, Director of the Center for Mind-Body Science and Health and faculty at the University of Pittsburgh, USA, and Dr. Kirk I. Erickson, Director of Translational Neuroscience and the Mardian J. Blair Endowed Chair of Neuroscience at the AdventHealth Research Institute, USA. They and their research team examined how meeting the physical activity recommendations of the American Heart Association can influence biological measures of stress and emotion, with a particular focus on the body's main stress hormone, cortisol.
The study included 130 adults who were 26 to 58 years old. The participants 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 information about health habits, but they did not change their physical activity levels. Over the course of the year, researchers monitored changes in cardiorespiratory fitness, cortisol, and several other measures of stress and emotion using brain imaging and other state-of-the-art techniques.
One of the standout findings was a significant reduction in long-term cortisol levels among participants who were in the exercise condition of the clinical trial. Cortisol is the body's key stress hormone that plays a role in many functions, including metabolism, immunity, sleep, memory, and mood regulation. High levels of cortisol are also linked to heart disease, metabolic disorders, and mental health conditions.
As Dr. Gianaros explained, "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."
The implications of this new clinical trial are significant, particularly because most of the research in this area is correlational and cannot establish cause-and-effect. The trial is also unique because no study has examined exercise and these measures of stress biology for a full year. Regular physical activity, as recommended by health guidelines, may be a simple yet effective behavioral strategy to mitigate the adverse effects of stress and improve quality of life.
A prior publication from this clinical trial also documented the benefits of exercise beyond cortisol levels. Using advanced brain imaging techniques, the trial showed that exercise may also slow the pace of brain aging.
Dr. Gianaros and Dr. Erickson hope that these new findings will draw more attention to the ways in which meeting the recommended goal of 150 minutes of physical activity per week may benefit mental resilience and overall health.
