CHANGES IN AEROBIC FITNESS OF MEN: AEROBICS CENTER LONGITUDINAL STUDY

Abstract

423 Longitudinal and cross-sectional data show that aerobic fitness(VO2max declines with age. Recent cross-sectional data (Jackson et al., Med. Sci. Sports Exerc. 1995) show that ≅50% of the age-related VO2max decline was due to exercise habits and body composition. The purpose of this study was to define the factors that affect the longitudinal age-related change in aerobic fitness. The subjects were 433 men who had 5 maximal treadmill tests. Published equations (R ≥ 0.9, SEE ≅ 1 MET) were used to estimate VO2max from max treadmill time. The sample characteristics (Mean ± SD) at test 1 (T1) were: age, 42.3 ± 8.4 yrs; and VO2max, 39.7 ± 5.7 ml/kg/min). The mean duration between tests (ΔT5 - T1) was 5.9 ± 3.0 yrs. Aerobic fitness significantly (p <0.001) increased between T5 and T1 at a mean rate of 0.39 ml/kg/year. Self-report physical activity (SR-PA) significantly increased (p<0.001) while weight (WT) showed a 0.55 kg increase between T1 and T5 (p<0.03). Multiple regression defined the variables that influenced the change. Using T5 aerobic fitness as the dependent variable, the significant(p< 0.001) independent variables of the regression model (R = 0.73. SEE = 4.1) were: T1 VO2max (0.68); ΔSR-PA (1.07); ΔWT (-0.11); and T1 age (-0.09). These analyses show that with initial aerobic fitness and age controlled, increases in SR-PA and decreases in WT have a positive influence on the longitudinal age-related change in aerobic fitness. The longitudinal age-related change in aerobic fitness is a multivariate problem and the regression equation provides a model to define individual changes