Objective: To evaluate the association of physical activity with left ventricular structure and function in the general population in a community setting.
Design: Cross-sectional study.
Setting: The Multi-Ethnic Study of Atherosclerosis (MESA), a population-based study of subclinical atherosclerosis.
Participants: A multiethnic sample of 4992 participants (aged 45-84 years; 52% female) free of clinically apparent cardiovascular disease.
Interventions: Physical activity induces beneficial physiological cardiac remodelling in a cross-sectional study of non-athlete individuals.
Main outcome measures: Left ventricular mass, volumes and function were assessed by cardiac magnetic resonance imaging. Physical activity, defined as intentional exercise and total moderate and vigorous physical activity, was assessed by a standard semiquantitative questionnaire.
Results: Left ventricular mass and end-diastolic volume were positively associated with physical activity (eg, 1.4 g/m(2) (women) and 3.1 g/m(2) (men) greater left ventricular mass in the highest category of intentional exercise compared with individuals reporting no intentional exercise; p = 0.05 and p<0.001, respectively). Relationships were non-linear, with stronger positive associations at lower levels of physical activity (test for non-linearity; p = 0.02 and p = 0.03, respectively). Cardiac output and ejection fraction were unchanged with increased physical activity levels. Resting heart rate was lower in women and men with higher physical activity levels (eg, -2.6 beats/minute lower resting heart rate in the highest category of intentional exercise compared with individuals reporting no intentional exercise; p<0.001).
Conclusions: In a community-based population free of clinically apparent cardiovascular disease, higher physical activity levels were associated with proportionally greater left ventricular mass and end-diastolic volume and lower resting heart rate.