An extrapolation procedure for determination of oxygen debt repayment.

Repayment of oxygen debt incurred during physical effort is determined by measuring the extra oxygen used above the resting value during a recovery period of 0.5 to 1 h. Since this imposes an additional stress on the experimental subject, an attempt has been made to develop a simple, quick, and accurate method for determining oxygen debt. The method described here is based on the fact that the curve describing recovery is the resultant of two exponential curves, one fast and one slow, the former being complete in less than 3 min. We have derived a mathematical equation by means of which the total oxygen debt measurable over a 60 min period can be extrapolated from the measurements of excess oxygen consumption over the resting value at the end of 3, 6, and 9 min of the recovery period. The equation has been validated by observations on 10 young healthy subjects at sea level and at high altitude. The results show that the equation has good predictive value.