Physical activity, atrial fibrillation and the dose-response relationship: a systematic review and meta-analysis

BACKGROUND AND AIM: Regular physical activity (PA) may reduce atrial fibrillation (AF) risk in the general population, however, contemporary data suggests individuals engaging in the highest levels of PA may exhibit a paradoxical rise in AF risk. The point at which the dose-response curve reverses remains unclear. This meta-analysis aimed to assess the association between PA and AF across the full continuum of PA exposure. METHODS: Four databases were searched (from January 1990 to June 2025). Eligible studies included those that reported PA exposure compared against a sedentary control group and assessed AF incidence or prevalence. PA exposures were standardised to metabolic equivalent of task hours per week (MET-hr/wk). Pooled odds ratios (ORs) were calculated using a weighted random-effects model. A weighted restricted cubic spline model of logarithmic odds was used to produce a dose-response curve. RESULTS: 37 studies were included (n = 1,298,291 individuals). In the general population, PA was associated with a reduction in odds of AF by 22% (22 studies; OR 0.78; 95% CI 0.68, 0.89). Athlete status was associated with an increase in the odds of AF (15 studies; OR 2.74; 95% CI 1.72, 4.39). Dose-response analysis (26 studies; n = 1,022,790 individuals) showed 26 MET-hr/wk of PA was associated with the greatest reduction in odds of AF, with doses beyond 78 MET-hr/wk associated with increased odds of AF; the equivalent of 6-7 hours per week of endurance training. CONCLUSION: PA and AF demonstrate a U-shaped relationship whereby beyond a quantitative dose threshold of 78 MET-hr/wk, the protective effect of exercise may reverse.