Physical Activity, Obesity, and Subclinical Myocardial Damage

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/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.

Keywords: epidemiology; heart failure; obesity; physical activity; troponin T.

Figure 1

Panel A Association of Quartiles* of Physical Activity with Odds Ratios (and 95% CIs) for Elevated Hs-cTnT Reference: Quartile 4: ≥1365.9 (mets*min)/week Adjusted for age, race, sex, smoking status, and alcohol use *Cutpoints for quartiles of physical activity: Quartile 1: 0–453.6 (mets*min)/wk; Quartile 2: 453.6–846.3 (mets*min)/wk; Quartile 3: 846.3–1364.9 (mets*min)/wk; Quartile 4: ≥1365.9 (mets*min)/wk Panel B Continuous Association Between Physical Activity and Elevated Hs-cTnT Among Participants Without Clinical CVD in Restricted Cubic Spline Models Reference: 95^th percentile, 2182 (MET*min)/week * Adjusted for age, race, sex, smoking status, and alcohol use

Figure 2

Adjusted Incidence Rates for Incident HF Associated with Elevated and Non-Elevated hs-cTnT Within Each Cross-Category of Physical Activity and Obesity Status * p values for the incidence rate difference between elevated and non-elevated hs-cTnT within each obesity/physical activity cross-category are < 0.001 for all groups