Scaling for the VO2-to-body size relationship among children and adults.

The purpose of this study was to examine the relationship between oxygen consumption (VO2) and both body surface area (BSA) and body size among 30 prepubertal children, 30 circumpubertal children, and 30 adults to determine which scaling model is most appropriate for making comparisons between these populations. All subjects participated in maximal treadmill testing and submaximal treadmill testing at two absolute work rates. Resting metabolic rate was measured on a subset of 48 subjects. It was determined that the submaximal VO2 (VO2 sm)-to-body size relationship provided the most appropriate model for comparisons. Analyses revealed a stronger linear relationship between VO2 sm and BSA than VO2 sm and body mass. Logarithmic transformation of the data revealed an allometric exponential relationship between VO2 sm and body mass. The exponent relating body mass to VO2 sm at 3 mph (1.34 m/s) was 0.60, whereas the exponent at 5 mph (2.24 m/s) was 0.75. VO2 values at 5 mph were significantly less variable (P < or = 0.05) than those at 3 mph. Therefore the exponent of body mass to the 0.75 power was considered a more appropriate basis for analysis. It was determined that, overall, a scaling factor of BSA or body mass to the 0.75 power both provide a more appropriate method of comparison than a simple ratio standard of body weight.