ALLOMETRIC SCALING OF VO2 MAX BY BODY-MASS AND LEAN BODY-MASS IN OLDER MEN

This study employed allometry to scale maximal oxygen uptake (VO2 max) by body mass (BM) and lean body mass (LBM) in healthy older men. Ratio standards (ml . kg(-1) . min(-1)) derived by dividing absolute VO2 max (L . min(-1)) by BM or LBM often fail to control for the body size variable. The subjects were 73 older men (mean +/- SD: age = 69.7 +/- 4.3 yrs, BM = 80.2 +/- 9.6 kg, height = 174.1 +/- 6.9 cm): VO2 max was assessed on a treadmill with the modified Balke protocol (VO2 max = 2.2 +/- 0.4 L . min(-1)). Body fat (27.7 +/- 6.4%) was assessed with dual energy x-ray absorptiometry. Allometry applied to BM and VO2 max determined the BM exponent to be 0.43, suggesting that heavier older men are being penalized when ratio standards are used. Allometric scaling applied to LBM revealed the LBM exponent to be 1.05 (not different from the ratio standard exponent of 1.0). These data suggest that the use of ratio standards to evaluate aerobic fitness in older men penalized fatter older men but not those with higher LBM.