Oxygen Debt and Rise of Blood Lactate During Submaximal Exercise in Relation to Physical Fitness and Endurance

Oxygen debt and rise of blood lectate during graded submaximal work were linearly related to each other and to work rate. They could also differentiate the physical fitness status of groups of individuals, being lower for better fit groups. Such differentiation was, however, possible only above work rates of the order of 500-600 kg.-m/min. The significance of this in submaximal tests for physical fitness is pointed out. Value of oxygen at which blood lactate begins to rise was significantly higher in better fit group. Oxygen debt and rise of blood lactate during a standard near maximal exercise could reflect work capacity in terms of maximum stepping time on a 16 in high stool.