Thermoregulation during rest and exercise in different postures in a hot humid environment

The time course of whole-body sweating and thermal regulation during rest and exercise in a hot humid environment was investigated in three body postures. After 45 min rest in the upright, low-sit, or supine posture, five unacclimatized men exercised for 45 min on a bicycle ergometer in the same pos...

Full description

Saved in:
Bibliographic Details
Published inJournal of applied physiology: respiratory, environmental and exercise physiology Vol. 48; no. 6; p. 999
Main Authors Kabayashi, K, Horvath, S M, Diaz, F J, Bransford, D R, Drinkwater, B L
Format Journal Article
LanguageEnglish
Published United States 01.06.1980
Subjects
Adult
Body Temperature Regulation
Heart Rate
Humans
Humidity
Male
Physical Exertion
Posture
Sweating
Online AccessGet more information

Cover

More Information
Summary:The time course of whole-body sweating and thermal regulation during rest and exercise in a hot humid environment was investigated in three body postures. After 45 min rest in the upright, low-sit, or supine posture, five unacclimatized men exercised for 45 min on a bicycle ergometer in the same posture in an environment of 49.5 degrees C, 28.9 Torr. Exercise was performed at two different work loads, corresponding to about 30 and 45% of VO2max. During exercise auditory canal temperature, rectal temperature, and mean skin temperature increased linearly being highest in the supine and lowest in the upright posture. Percentage of evaporated sweat from the skin to secreted sweat was 65% in upright, 52% in the low-sit, and only 46% in the supine posture during the last 20 min of exercise regardless of work load. The time course of the rate of body heat storage was different from predictions based on the thermal balance equation. Evaporative heat loss was not 100% effective in cooling the skin surface.
ISSN:0161-7567
2691-2465
DOI:10.1152/jappl.1980.48.6.999