Cross-sectional relationships of exercise and age to adiposity in 60,617 male runners.

Abstract

To assess in men whether exercise affects the estimated age-related increase in adiposity, and contrariwise, whether age affects the estimated exercise-related decrease in adiposity. Cross-sectional analyses of 64,911 male runners who provided data on their body mass index (97.6%) and waist circumference (91.1%). Between 18 and 55 yr old, the decline in BMI with weekly distance run (slope +/- SE) was significantly greater in men 25-55 yr old than in younger men (slope +/- SE: -0.036 +/- 0.001 vs -0.020 +/- 0.002 kg x m(-2) per km x wk(-1)). Declines in waist circumference with distance were also significantly greater in older than younger men (P < 10(-9)), that is, the slopes decreased progressively from -0.035 +/- 0.004 cm per km x wk(-1) in 18- to 25-yr-old men to -0.097 +/- 0.003 cm per km x wk(-1) in 50- to 55-yr-old men). Increases in BMI with age were greater for men who ran under 16 km.wk(-1) than for relatively longer distance runners. Waist circumference increased with age at all running distances, but the increase diminished by running further (0.259 +/- 0.015 cm x yr(-1) if running <8 km x wk(-1) and 0.154 +/- 0.003 cm x yr(-1) for >16 km x wk(-1)). In men 50-85 yr old, BMI declined -0.038 +/- 0.001 kg x m(-2) per km x wk(-1) run when adjusted for age and declined -0.054 +/- 0.003 kg x m(-2) (increased 0.021 +/- 0.007 cm) per year of age when adjusted for running distance. Their waist circumference declined -0.096 +/- 0.002 cm per km x wk(-1) run when adjusted for age and increased 0.021 +/- 0.007 cm per year of age when adjusted for running distance. These data suggest that age and vigorous exercise interact with each other in affecting men's adiposity and are consistent with the proposition that vigorous physical activity must increase with age to prevent middle-age weight gain.