Peripheral Changes in Regional Sweating Responses to Exercise in Hypobaric Environments

摘要

The effect of hypobaric hypoxia on the relation of regional sweating to body temperature rise was studied in four men and four women (follicular phase of menstrual cycle) who exercised 40 and 60% of their altitude specific peak aerobic power at 770 Torr (sea level), 552 Torr (2596m), and 428 Torr (4575m) in 20 C or 30 C for 35 minutes. Body temperature and sweating at the chest (C), arm (A) and thigh (T) were measured continuously from dew point sensors attached to the skin. No gender differences were found in either the sensitivity (slope) or the threshold of the sweating to body temperature for any site during any combination of exercise intensity, altitude or environmental temperature. In all experimental conditions, the mean body temperature threshold for the initiation of A (36.7 C) sweating was higher (P<0.05) than C (36.5 C). The mean slopes of the sweating to body temperature relationships for the three regional sites during the exercise-temperature combinations decreased with increasing altitude. Our data indicate that there are peripheral components active in the regional sweating to body temperature relationship that occur in hypobaric hypoxia. Enhanced body cooling as a response to the higher evaporative capacity of the environment may be a component of these peripheral differences occurring in hypobaric hypoxia.