Higher fitness levels may protect against atrial fibrillation
Research we're watching
- Reviewed by Christopher P. Cannon, MD, Editor in Chief, Harvard Heart Letter; Editorial Advisory Board Member, Harvard Health Publishing
People with a high exercise capacity may be less likely to develop fibrillation (afib), a new study finds.
Researchers followed more than 15,000 people who underwent exercise stress testing, measuring their peak exercise capacity in metabolic equivalents (a standard measure used to gauge exertion, called METs). During the median follow-up period of nine years, 515 (3.3%) of them developed afib.
For every one-MET increase in exercise capacity, there was an 8% lower risk of developing afib. This protective effect was strongest in people over 50 and those without heart rate problems during exercise. The higher a person’s capacity, the lower the risk of afib. And there was no minimum threshold, meaning even modest fitness improvements helped. Higher exercise capacity also independently reduced risks of stroke and major cardiovascular problems.
Published online Aug. 6, 2025, by JACC Asia, the findings suggest that maintaining good cardiovascular fitness through regular physical activity should be a key strategy for preventing afib and its serious complications.
Image: © Jordan Siemens/Getty Images
About the Author
Julie Corliss, Executive Editor, Harvard Heart Letter
About the Reviewer
Christopher P. Cannon, MD, Editor in Chief, Harvard Heart Letter; Editorial Advisory Board Member, Harvard Health Publishing
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