Comparison of Cardiac Output during Work with Arms or Legs at Equal Work Loads

Abstract

The effects of arm work and leg work on cardiac output (Q) and some other physiological parameters were studied in ten Japanese males. The subjects performed the work using arms or legs in a sitting position, with equal work loads of 150, 300, and 450kgm/min. Oxygen uptake (Vo2) and heart rate (HR) during arm work were significantly (P<0.01) higher than those during leg work at the loads of 300 and 450 kgm/min. With the increase of work loads, stroke volume (SV) during leg work was elevated, whereas no significant changes in SV occurred during arm work. At the heaviest load, SV during arm work was significantly (P<0.05) lower than that during leg work. There was no siginificant difference in Q between arm work and leg work at a given work load. The regression equation of Q(1/min ; Y) on Vo2 (ml/min ; X) was calculated for arm work and leg work, respectively, which was Y=2.37+0.00707X for arm work, and was Y=0.779+0.00968X for leg work. Analysis of covariance showed that the elevation of the regression equation calculated for arm work was significantly (P<0.05) lower than that for leg work. The regression equations of Q on Xo2 obtained during arm work and leg work in the present study were compared with those of some previous studies (BEVEGARD et al., 1966; STENBERG et al., 1967). Analysis of covariance indicated that those regression equations obtained during leg work were significantly different among each other. It should be noted that there were no significant differences in those regression equations obtained during arm work.