Exercise VO2 estimation using recovery sampling

Various situations present a challenge to determine oxygen uptake (VO2) accurately simply because of the restrictions imposed by the equipment employed. This investigation was undertaken to 1) compare a select number of recovery VO2 measurements with respect to their accuracy in estimating actual exercise VO2 and 2) to determine whether absolute workload or VO2max affect this relationship. Fifteen subjects [8 highly trained (HT), VO2max +/- SD = 70.2 +/- 3.5 ml/kg . min-1 and 7 untrained (UT), VO2max = 49.7 +/- 3.8 ml/kg . min-1] completed a number of 5 min workbouts on a bicycle ergometer at 25-70% VO2max (VO2 = .899--3.879 l . min-1). VO2 and VCO2 (l . min-1) were monitored continuously throughout the exercise and for 5 min of recovery via a breath-by-breath system. The results indicated that 1) exercise VO2 +/- Sy.x can be estimated from several recovery collection periods, the first breath y = .953X + .441 +/- .319, the first two breaths y = 1.046X + .327 +/- .270, the first three breaths y = 1.089X + .260 +/- .241, and the second three breaths y = 1.101X + .387 +/- .234, and 2) VO2max does not affect this relationship (p greater than 0.05) while increasing absolute workload produces a greater exercise VO2 underestimation (p less than 0.05). It was concluded that using this method exercise VO2 can be estimated with reasonable accuracy (Sy.x = .234--.319, r = .92--.94, p less than 0.01).