Abstract
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/m(2). 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.