抄録
This study was designed to determine if the effects of change in exercise rhythm on physiological responses could be reduced by the control of breathing during exercise. Seven healthy volunteers, four women and three men, took part in this study as subjects. The responses of breath ing rhythms to increased exercise rhythms and the intensity were examined under two breathing conditions, normal breathing (NB) and controlled frequency breathing (CFB) whose breathing frequency was 20f/min and entrained exercise rhythms. In both conditions, work intensity was 1 kp and base line pedaling rate was controlled with 40 rpm. As a change of exercise rhythms, the pedaling rate was changed to 1 min every 4 min in order of 60, 80 and 100 rpm in 19 min exercise. At the change in exercise rhythms in CFB condition, VE and VCO_2 increased with elevation of work intensity enough to exhaust produced C0_2. The slope of the regression line with PETC0_2/VC0_2 expressed as ventilatory efficiency was significantly efficient in CFB compared with NB condition. Heart rate (HR) responses were shown similar with the change of exercise rhythm in both conditions, however in NB condition, the correlation between change in breathing frequency and change in HR was significant. These results suggest that the control of breathing improved ventilatory efficiency at the change in exercise rhythms and work intensities.
