Oxygen deficit and repayment in submaximal exercise.

Oxygen deficit and repayment ratios were investigated at various work loads, intensities and durations. An active baseline was used (walking at 60 m/min) from which deficit and repayment values were calculated. Oxygen uptake (VO2) and core temperatures were measured in 30 males at baseline and during treadmill running (140 m/min) for randomly assigned durations (0.5 ...20 min). Measurements were also made during a 30-min recovery period at baseline work. Results indicated: 1) No difference in O2-repayment between steady-state work and work prior to steady state (P greater than 0.10). 2) O2-repayment was independent of work duration (P greater than 0.10). 3) When workload and intensity were controlled, O2-deficit was not significant factor in O2-repayment (P greater than 0.10). 4) Work intensity (work VO2/VO2 max) was the most significant factor in O2-repayment accounting for 69% of the variance (r equals 0.83, P less than 0.001). Small increments in core temperature and ventilation were not significant factors in O2-repayment. When a working baseline is used, the magnitude of O2-repayment after exercise is independent of the work duration or the attainment of steady state. The extent of O2-repayment after exercise is mainly dependent upon the physiological intensity of the work and the absolute workload (R=0.89, P less than 0.001).