In an attempt to obtain the fundamental data for the safety in exercise under cold environment, the present study was performed to examine the effect of abrupt change of ambient temperature (Ta) on respiratory-cardiovascular and thermoregulatory responses during exercise. Each of six healthy adult males pedalled a bicycle ergometer for 60 minutes at light and heavy load (approximately 40 and 60% VO₂max) in given 5, 10 and 25℃ Ta, respectively, after 80-minutes resting in sitting posture under 25℃ Ta. Heart rates, systolic blood pressure (SBP), ECG parameters, O₂ consumption, rectal (Tre) and mean skin temperatures were measured. At the beginning of exercise, SBP and O₂ consumption were increased more markedly in 5℃ (especially at light load) and 10℃ Ta than those in 25℃ Ta. The exercise in 5℃ and 10℃ Ta resulted in lower heart rates than those observed in 25℃ Ta. ECG parameters and Tre were almost independent of Ta in every experiment. These results suggested that a remarkable initial rise of SBP might be a risk factor against the safety in winter sports.

DESCENTE SPORTS SCIENCE Vol.5/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE