The purpose for this study is to understand response in respiratory and circulatory function at the start of exercise expired air through breath by breath analysis.
　1. Three healthy volunteers were subject for the study. An examination consisted of a 2 min unloaded period followed by cycling (approx 60 rpm) on a Monark ergometer, at 1.5, 2.5, 3.5, 4.5, 5.5 KP of 3 min each.
　2. The relationship between aerobic work capacity and response at the start point of exercise was: even VO₂max rated approximately the same at 5.5 KP work load, the heart rate of subject who had been training had rated larger. On the other hand, we did not success to identify any inclination in VO₂.
　3. The higher the work load, the ventilation had been increased. Respiration rate didn't change from 1.5 KP to 4.5 KP work but at 5.5 KP work load, it increased rapidly at the latter half of exercise.
　4. As for the rate of expiration time, in respect of anaerobic 5.5 KP, rated 30% to 40% at the start point of exercise decreased and eventually, as it approached to exhaustion point, decreased to 15%. Furthermore, subject with higher VO₂ had slower declination.

DESCENTE SPORTS SCIENCE Vol.26/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE