Characterizing O2 Uptake Response Kinetics During Exercise

It has recently been proposed that the half time for the kinetics of VO2 during exercise may be accurately determined from a linear fit to the exponential response on linear coordinates. We demonstrate that although this is the case for two periods of data utilization, it is not true for any others, and that small variations in this period markedly influence the estimate. Furthermore, it is necessary to know the parameters of the response to determine the appropriate period of data collection. We conclude that the proposed linear estimation procedure is likely to yield erroneous values for VO2 kinetics during exercise.