Sedentary behavior with atrial fibrillation-related biomarkers in overweight or obese adults

BACKGROUND: Blood biomarkers can characterize the atrial substrate and help elucidate mechanisms of atrial fibrillation (AF) development. Understanding whether sedentary behavior affects AF-related biomarkers may inform prevention strategies. METHODS: We studied 252 participants in PREDIMED-Plus, a multicenter randomized trial in Spain for the primary prevention of cardiovascular disease. Participants wore wrist accelerometers for one week at baseline and at least once during follow-up (years 3 or 5). Blood samples were collected at each time point to measure selected biomarkers: propeptide of procollagen type I, high-sensitivity (hs) troponin T (hsTnT), hs C-reactive protein, 3-nitrotyrosine, and N-terminal propeptide of B-type natriuretic peptide (NT-proBNP). Using isotemporal substitution, we estimated the effect of replacing 30 min/day of sedentary time (< 1.5 METs in waking time) with low-intensity physical activity (LPA, 1.5-3 METs), moderate-to-vigorous PA (MVPA, > 3 METs), or time in bed (bedtime to wake-up) on log-transformed biomarker levels, cross-sectionally and longitudinally, via linear regression and mixed models. RESULTS: At baseline, participants (mean age 65 ± 4.9 years, BMI 32.2 ± 3.3 kg/m², 40% women) showed no significant cross-sectional associations between substituting sedentary time and biomarker levels. After 5 years, replacing baseline 30-min of sedentary time per day with LPA or MVPA was associated with lower hs-TnT concentrations compared to baseline (-4%, 95% CI -8%, -1%; and - 2%, 95% CI -7%, 4%). Substitutions showed nonsignificant reductions in NT-proBNP but no consistent associations with other biomarkers. CONCLUSIONS: Among overweight/obese individuals, replacing sedentary time with PA was associated with favorable 5-year changes of hs-TnT, but not other AF-related biomarkers. TRIAL REGISTRATION: The trial was registered on July 24, 2014, at ISRCTN (ISRCTN89898870) [www.isrctn.com/ISRCTN89898870 (accessed on December 10, 2025)].