The Effects of Prolonged Muscular Work on Oxygen Intake, Heart Rate and the Relation between Both of Them

Abstract

Under a normal temperature environment we studied the effects of prolonged muscular work on heart rate and oxygen intake and the relation between both of them.The subjects were six healthy young male students (Table 1). They carried out one-hour work with a bicycle ergometer of 30, 40, 50 and 60% of their maximal oxygen intakes. This led to mean rectal temperature increases respectively 0.4, 0.6, 0.9 and 1.4°C. Submaximal work at first 30% and then 50% was carried out for 7 minutes each before and after the one-hour work. Pulmonary ventilation, oxygen intake, heart rate and rectal temperature were measured during these pre and post periods. Subjects carried out twice each experiment.When one-hour work at 50 and 60% was carried out, oxygen intake and heart rate taken during post submaximal works were significantly increased in comparison with those taken during pre submaximal works.It was also confirmed that the regression line of oxygen intake on heart rate was significantly shifted toward right after the prolonged muscular works and that this tendency was much more remarkable when the intensity of prolonged work was high (Fig. 1 & Table 5, 6). These results were discussed comparing with the effect of high temperature condition on heart rate and oxygen intake.