Scaling oxygen uptake to body size and several practical applications

Abstract

Oxygen uptake (VO2) has typically been expressed in milliliters per kilogram per minute to equate people of different body masses. However, research suggests that VO2 increases in proportion to body mass raised to a power between 0.6 and 0.75, rather than in proportion to body mass raised to a power of 1. The potential for several errors arises when using a body mass exponent of 1 (ml·kg-1·min-1), and these include the following: (a) penalizing larger subjects and inflating the scores of lighter subjects when comparing maximal aerobic capacity scores, (b) inaccurately estimating aerobic capacity via submaximal tests, causing misinterpretations of those scores, and (c) reducing accuracy in the assessment of movement economy and the energy cost of physical activity. Expressions of VO2 scaled to body mass to a power less than 1 tend to minimize the bias and errors associated with linear-relative expressions (ml·kg-1·min-1). The purpose of this article is to briefly review recent literature related to the scaling of VO2 to body size and to consider some of the practical applications suggested by the review. These implications appear to be important for fitness professionals, strength and conditioning coaches, and exercise scientists.