Oxygen Uptake Kinetic Response to Exercise in Children

The oxygen uptake (V̇O2) kinetic response to exercise assesses the integrated response of the cardiovascular system and the metabolic requirements of the exercising muscle. The response differs both qualitatively and quantitatively according to the exercise intensity domain (moderate, heavy, very heavy and severe) in which it lies. In each domain, a rapid cardiodynamic phase 1 response is followed by an exponential rise in V̇O2 toward a projected steady state (for which the inverse of the rate constant is represented as the time constant [τ]). The achievement of the new steady state may be delayed and elevated due to a slow component of V̇O2 in the heavy intensity domain, or above this exercise intensity, the achievement of peak V̇O2 truncates the exercise period. For each of these domains, specific mathematical models have been identified and may be applied to appropriate breath-by-breath response data in order to allow quantification of the response.