Modelling the influence of age, body size and sex on maximum oxygen uptakein older humans

The purpose of this study was to describe the influence of body size and se x on the decline in maximum oxygen uptake ((V) over bar (O2,max)) in older men and women. A stratified random sample of 152 men and 146 women, aged 55 -86 years, was drawn from the study population. influence of age on (V) ove r bar (O2,max), independent of differences in body mass (BM) or fat-free ma ss (FFM), was investigated using the following allometric model: (V) over b ar (O2,max) = BMb (or FFMb)exp(a + (e x age) + (d x sex))epsilon. The model was linearised and parameters identified using standard multiple regressio n. The BM model explained 68.8% of the variance in (V) over bar (O2,max). T he parameters (+/- S.E.E., standard error of the estimate) for InBM (0.563 +/- 0.070), age (-0.0154 +/- 0.0012), sex (0.242 +/- 0.024) and the interce pt (-1.09 +/- 0.32) were all significant (P < 0.001). The FFM model explain ed 69.3% of the variance in (V) over bar (O2,max) and the parameters (+/- S .E.E) InFFM (0.772 +/- 0.090), age (-0.0159 +/- 0.0012) and the intercept ( -1.57 +/- 0.36) were significant (P < 0.001), while sex (0.077 +/- 0.038) w as significant at P = 0.0497. Regardless of the model used, the age-associa ted decline was similar, with a relative decline of similar to 15% per deca de (0.984 exp(age)) in (V) over bar (O2,max) in older humans being estimate d. The study has demonstrated that, for a randomly drawn sample, the age-re lated loss in (V) over bar (O2,max) determined, in part, by the loss of fat -free body mass. When this factor is accounted for, the loss of (V) over ba r (O2,max) across age is similar in older men and women.