ABSTRACT
To examine the influence of warm-up on thermoregulatory responses during exercise, heat balance was measured in 5 healthy male students during lhr of exercise at 600 kpm/min work intensity in a climatic room of WBGT (Wet-Bulb Globe Temperature) at 30°C with or without pre-exercise warm-up at the minimum phase (6: 00-7: 00) of body temperature.<BR>There was no significant difference in heat production between exercise with and without warm-up. Evaporative heat loss during exercise with warm-up was 4-8% higher than that without warm-up.<BR>Warm-up did not influence dry heat loss. Body heat storage during exercise without warm-up was 36% higher than that with warm-up.<BR>The slope of the characteristic curve between the sweating response and elevation of rectal temperature during exercise with warm-up was higher than that without warm-up. These results indicate that the increased evaporative heat loss resulting from warm-up is brought about by changes in the sensitivity of the thermoregulatory response.