Faster adjustment to and recovery from submaximal exercise in the trained state.

This study was undertaken to evaluate the effects of endurance exercise training on O2 deficit and O2 debt, and on the time courses of the adjustment to, and recovery from, submaximal exercise of oxygen uptake (VO2) carbon dioxide production (VCO2), minute ventilation (VE), and heart rate (HR). Eight subjects participated in a 9-wk-long exercise program that increased their VO2max by 24%. It was found that O2 deficit and O2 debt were lower at the same absolute work rate and not significantly different at the same relative work rate after training. The increases in VO2, VCO2, VE, and HR at the onset of constant load submaximal work, and the decreases in VO2, VCO2, VE, and HR in recovery were more rapid at both the same absolute and the same relative work rates after training. These results show that the adaptations to endurance exercise training enable an individual to adjust to the energy requirement of constant load submaximal work more rapidly, resulting in a smaller O2 deficit. The rate of recovery is also more rapid after training, resulting in a smaller O2 debt.