We examined in cardio-respiratory responses on treadmill walking and running for six healthy men, four of them were long distance runner of a university. Exercise stresses (walking and running pace) were selected by subjects carrying remote control switch, and running within fifteen minutes until optimum speed, which they felt by themselves, not for competitive running pace or exhaustion. We measured in ten seconds interval from lower speed to the optimum speed. Heart rate and expired gas were analyzed by real time computerized calculating system.
　There were some cases that even thought heart rate was in steady state, but oxygen intake was not steady. Comparatively the running pace which selected by the subject easy for walking or running, there seemed to be steady in heart rate, oxygen intake and oxygen removal. Therefor under the selected speed for the subject, there was high correlation between oxygen intake and oxygen removal.
　By the way, it was speculated that setting exercise stress test has the object that a few different exercise condition reveal more different results especially on respiratory responses. We need more research that physically and psychologically and subjectively considered exercise stress test method.

DESCENTE SPORTS SCIENCE Vol.8/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE