Association of physical activity to cardiovascular fitness and fatness in 12-13-year-old boys in different weight status

Aim The aim was to examine the associations between physical activity (PA) and cardiovascular fitness (CVF) and fatness in boys (age 12.04 +/- 0.77 year) and to assess if weight status influences these associations. Subjects and methods Two hundred sixty-five boys participated in the study. PA was measured by accelerometry. Body fatness estimators included body mass index (BMI), body fat%, sum of five skinfolds and waist circumference. CVF was directly measured during stepwise incremental exercise test and expressed in peak oxygen uptake (VO2peak) and maximal power output (W-max). Results All measured PA levels (except vigorous PA in obese boys) were significant predictors of Wmax per kilogram of body mass in normal weight and obese boys. Vigorous PA, moderate-to-vigorous PA (MVPA), total PA in normal weight and vigorous PA in obese boys were significant predictors of W-max. Variation in VO2peak per kilogram of body mass was significantly explained by moderate PA, vigorous PA, MVPA and total PA in normal weight only. For those of normal weight, vigorous PA, MVPA and total PA were negatively associated with body fat% and sum of five skinfolds. In obese boys, moderate PA and MVPA were negatively associated with BMI. Conclusions Time spent in vigorous PA and MVPA was associated with fatness parameters in normal weight and obese boys and with CVF parameters only in normal weight boys. Normal weight boys spent more time in vigorous PA and MVPA than overweight and obese boys and had high values in VO2peak, VO2peak per kilogram of body mass and W-max per kilogram of body mass.