Oxygen uptake (VO2) kinetics in different species: a brief review

Abstract

AbstractWhen a human begins to move or locomote, the energetic demands of its skeletal muscles increase abruptly and the oxygen (O2) transport system responds to deliver increased amounts of O2to the respiring mitochondria. It is intuitively reasonable that the rapidity with which O2transport can be increased to and utilized by (VO2) the contracting muscles would be greater in those species with a higher maximal VO2capacity (i.e., VO2max). This review explores the relationship between VO2maxand VO2dynamics or kinetics at across a range of species selected, in part, for their disparate VO2maxcapacities. In healthy humans there is compelling evidence that the speed of the VO2kinetics at the onset of exercise is limited by an oxidative enzyme inertia within the exercising muscles rather than by VO2delivery to those muscles. This appears true also for the horse and dog but possibly not for a certain species of frog. Whereas there is a significant correlation between VO2maxand the speed of VO2kinetics among different species, it is possible to identify species or individuals within a species that exhibit widely disparate mass-specific VO2maxcapacities but similar VO2kinetics (i.e., superlative human athlete and horse).