Physical Activity, Obesity, and Subclinical Myocardial Damage

Objectives This study sought to evaluate the association of physical activity with chronic myocardial damage, assessed by elevated high-sensitivity cardiac troponin T (hs-cTnT), in individuals with and without obesity. Background Physical activity is associated with reduced risk of heart failure (HF), particularly among obese people. The role of chronic myocardial damage in this association is uncertain. Methods We studied 9,427 participants in the Atherosclerosis Risk in Communities Study without cardiovascular disease, with body mass index >18.5 kg/m². Physical activity was categorized per American Heart Association guidelines as recommended, intermediate, or poor. We evaluated cross-sectional associations of physical activity and obesity with elevated hs-cTnT (≥14 ng/l). In prospective analyses, we quantified the association of elevated hs-cTnT with HF risk within cross-categories of baseline physical activity and obesity. Results People with poor physical activity were more likely to have elevated hs-cTnT than those with recommended levels (odds ratio [OR]: 1.39; 95% confidence interval [CI]: 1.15 to 1.68). In cross-categories of physical activity and obesity, using the non-obese/recommended activity group as the reference, individuals with obesity and poor activity were most likely to have elevated hs-cTnT (OR: 2.46; 95% CI: 1.91 to 3.19), whereas the obese/recommended activity group had a weaker association (OR: 1.68; 95% CI: 1.28 to 2.21; p < 0.001 for interaction between physical activity and obesity). In prospective analyses, elevated hs-cTnT was strongly associated (p < 0.001) with incident HF in all obesity/physical activity cross-categories (p > 0.20 for interaction). Conclusions Physical activity is inversely associated with chronic subclinical myocardial damage. Physical activity might lessen the association between obesity and subclinical myocardial damage, which could represent a mechanism by which physical activity reduces HF risk.