Cardiovascular
Effect of replacing sedentary behavior with physical activity on the risk of atrial fibrillation: the REGARDS study Linzi Li* Linzi Li Amit Shah Yi-An Ko Dayna A. Johnson Yan V. Sun Emily B. Levitan Virginia J. Howard Suzanne E. Judd Elsayed Z. Soliman Alvaro Alonso
Background
Prolonged sedentarism has been identified as a distinct cardiovascular risk factor separate from physical activity (PA), but its impact on atrial fibrillation (AF) risk when replaced with PA is unclear.
Methods
We studied 5777 participants in the REGARDS cohort, excluding those with prevalent AF, missing data on AF incidence, and missing accelerometry. Sedentary behavior (SB) and PA were objectively measured via accelerometry between May 2009 and January 2013. Incident AF was identified during follow-up visit through electrocardiograms and by self-reported medical history between May 2013 to December 2016. SB was assessed as sedentary time per day and as a percentage of accelerometer wear time (excluding sleep). PA was categorized into light (LPA) and moderate to vigorous (MVPA), as well as the corresponding percentages of total wear time. Using logistic regressions, we applied isotemporal substitution to examine the effect of replacing 30-minute sedentary time or 1% of sedentary time per day with equivalent durations or percentages of each type of PA on AF risk, adjusting for demographic, clinical, and behavioral covariates.
Results
The study sample had an average age of 63 (SD 8.3) years, with 55% females, 45% males, 31% and 69% Black and White adults. On average, participants engaged in 686.5 (SD 116.1), 193 (SD 76.9), and 14.1 (SD 18.0) minutes of SB, LPA, and MVPA per day, with 486 AF cases identified. Substituting 30-min SB per day with MVPA was associated with decreased odds of AF (OR 0.79, 95% CI 0.62, 1.00) after adjustment for covariates, whereas LPA showed no association. Similarly, replacing 1% of sedentary time with MVPA was linked to decreased odds of AF (OR 0.93, 95% CI 0.87–1.00), but no association was observed for LPA.
Conclusion
Replacing SB with PA with moderate or higher intensity may decrease AF risk. These findings highlight the potential benefits of reducing sedentarism to lower AF burden, warranting validation in future studies.