Background— Higher levels of physical activity are associated with reduced cardiovascular mortality but its effect on age-related changes in cardiac structure and function is unknown. The present study defines the effect of daily physical activity on age-related changes in cardiac structure, function, metabolism, and performance in healthy women. Methods and Results— Sixty-three healthy women were grouped according to age (young, 20–30 years, n=21; middle, 40–50 years, n=22; and older, 65–81 years, n=20) and daily physical activity level (low active <7500 and high active >12 500 steps/d). Participants underwent cardiac MRI including tissue tagging and 31 P spectroscopy and exercise testing with noninvasive central hemodynamic measurements. Aging was associated with increased concentric remodeling ( P <0.01) and left ventricular torsion ( P <0.01), and a decline in diastolic function ( P <0.01), cardiac phosphocreatine:ATP ratio ( P <0.01), peak exercise cardiac power output ( P <0.01), and O 2 consumption ( P <0.01). Older high-active women demonstrated a phosphocreatine:ATP ratio and relative peak O 2 consumption similar to young low-active women, and 23% and 26% higher than older low-active women (phosphocreatine:ATP ratio, 1.9±0.2 versus 1.4±0.1; P <0.05 and O 2 consumption, 24.1±3.8 versus 17.8±2.0 mL/[kg·min]; P <0.01). In older women, physical activity had no effect on eccentricity ratio (0.9±0.2 versus 0.8±0.1 g/mL; P =0.19), E/A ratio (1.3±0.5 versus 1.4±0.5; P =0.66), torsion (7.6±1.7 versus 8.0°±2.1°; P =0.20), and peak cardiac power output (3.4±0.7 versus 3.4±0.8 W; P =0.91). Conclusions— A higher level of daily physical activity preserves cardiac metabolism and exercise capacity with aging but has limited effect on age-related changes in concentric remodeling, diastolic function, and cardiac performance.

No abstract