PREDICTORS OF AGE-ASSOCIATED DECLINE IN MAXIMAL AEROBIC CAPACITY - A COMPARISON OF 4 STATISTICAL-MODELS

Studies assessing changes in maximal aerobic capacity (V(over dot)O-2m ax) associated with aging have traditionally employed the ratio of V(o ver dot)O-2max to body weight. Log-linear, ordinary least-squares, and weighted least-squares models may avoid some of the inherent weakness es associated with the use of ratios. In this study we used four diffe rent methods to examine the age-associated decline in V(over dot)O-2ma x in a cross-sectional sample of 276 healthy men, aged 45-80 yr. Sixty -one of the men were aerobically trained athletes, and the remainder w ere sedentary. The model that accounted for the largest proportion of variance was a weighted least-squares model that included age, fat-fre e mass, and an indicator variable denoting exercise training status. T he model accounted for 66% of the variance in V(over dot)O-2max and sa tisfied all the important general linear model assumptions. The other approaches failed to satisfy one or more of these assumptions. The res ults indicated that V(over dot)O-2max declines at the same rate in ath letic and sedentary men (0.24 l/min or 9%/decade) and that 35% of this decline (0.08 l.min(-1).decade(-1)) is due to the age-associated loss of fat-free mass.