Summary: We’ve long known that a run can clear your head, but a landmark one-year randomized clinical trial has finally mapped the long-term biological “why.” The study is the first to prove a cause-and-effect relationship between aerobic exercise and a sustained reduction in cortisol, the body’s primary stress hormone.
By simply meeting the standard 150-minute weekly exercise goal, participants effectively lowered the biological “background noise” of stress.
Key Findings
- The Cortisol Drop: Exercisers showed a significant reduction in long-term cortisol levels. This suggests that regular cardio doesn’t just help you “relax” in the moment; it lowers your body’s baseline stress setting.
- Slowing Brain Aging: Prior data from this same trial revealed that the exercise group also showed a slower pace of brain aging, suggesting that physical activity protects the “hardware” of the brain alongside its chemistry.
- Mental Resilience: By mitigating the adverse effects of cortisol, the 150-minute-per-week threshold appears to be a “sweet spot” for building biological resilience against depression, anxiety, and heart disease.
- Long-Term Evidence: This is the first study of its kind to track these specific stress biomarkers over an entire year, providing the most robust evidence to date that exercise is a legitimate medical intervention for stress.
Source: Journal of Sport and Health Science
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.
Funding information
This study was funded by the National Institutes of Health and the National Heart, Lung, and Blood Institute (grant number: P01 HL040962) awarded to the University of Pittsburgh.
Key Questions Answered:
A: Yes. That’s just 30 minutes, five days a week. The study found that sticking to this “moderate” goal for a year was enough to fundamentally lower the amount of stress hormone circulating in the body.
A: Cortisol is great for “fight or flight,” but when it stays high because of modern work or life stress, it starts damaging your heart, disrupting your sleep, and literally shrinking parts of your brain. Exercise acts as a “drain” for that build-up.
A: No. You should always talk to your doctor. However, this study proves that exercise should be considered a “first-line” behavioral strategy, right alongside therapy and medicine, for managing the long-term biological effects of stress.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this exercise and stress research news
Author: Linjia Wang
Source: Journal of Sport and Health Science
Contact: Linjia Wang – Journal of Sport and Health Science
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Effects of a year-long aerobic exercise intervention on neuroendocrine, autonomic, and neural correlates of stress, emotion, and cardiovascular disease risk in midlife adults” by Peter J. Gianaros, Lu Wan, Mia K. DeCataldo, Cristina Molina Hidalgo, Mark R. Scudder, George Grove, Abigail Shell, Chae Ryon Kang, E. Lydia Wu-Chung, Anna L. Marsland, Thomas W. Kamarck, Javier Rasero, and Kirk I. Erickson. Journal of Sport and Health Science
DOI:10.1016/j.jshs.2026.101135
Abstract
Effects of a year-long aerobic exercise intervention on neuroendocrine, autonomic, and neural correlates of stress, emotion, and cardiovascular disease risk in midlife adults
Purpose
Test whether an aerobic exercise intervention that improves cardiorespiratory fitness reduces (a) biomarkers of cardiovascular disease (CVD) risk and (b) indicators of stress- and emotion-related neuroendocrine, autonomic, and neural activity.
Methods
In a preregistered 12-month clinical trial, 130 healthy adults aged 26 to 58 years (mean age = 41.4 years; 67.7% female) were randomized to (a) a 150min per week of moderate-to-vigorous aerobic exercise group or (b) health-information control group. Intervention effects were examined for: (a) cardiometabolic and vascular risk factors (triglycerides, total cholesterol, high-density lipoproteins, glycosylated hemoglobin, pulse-wave velocity); (b) indicators of neuroendocrine and autonomic activity (hair cortisol, heart rate variability); (c) biomarkers of systemic and vascular inflammation (interleukin-6, intercellular adhesion molecule-1); and (d) neural, cardiovascular, and subjective responses to functional magnetic resonance imaging stressor and emotion task paradigms.
Results
There were 41 and 40 participants in the exercise and control groups, respectively, who completed follow-up assessments. In planned intention-to-treat analyses using generalized linear mixed models, a group-by-time interaction indicated that the exercise group exhibited a decrease from baseline to follow-up relative to the control group in hair cortisol (Between-Group Difference = –0.62; 95% confidence interval (95%CI): –1.14 to –0.10, p(False Discovery Rate) = 0.039). This reduction was also observed in per protocol analyses. No other effects on remaining outcomes were consistently observed in planned and per protocol analyses.
Conclusion
A 12-month moderate-to-vigorous aerobic exercise intervention that improved cardiorespiratory fitness also reduced the stress-related biomarker, hair cortisol, but not other indicators of psychological stress and negative emotion processes implicated in CVD risk.
