title: Orthostatic responses in heat tolerant and intolerant subjects compared by three different methods.
abstract: The orthostatic responses of 10 heat tolerant and five intolerant subjects were evaluated by three different test methods--standing, head-up tilt (HUT), and head-up tilt after prolonged exercise (HUTPE)--in a hot environment of 40 degrees C, 40% RH. No difference was found within the normal group between responses in the standing and HUT test. In the HUTPE test, orthostatic responses were inadequate and 5 of 10 subjects fainted. The heat intolerant subjects reacted to all three tests similarly to the normal group, though their heart rate was higher and 3 out of 5 fainted at an earlier phase in the HUTPE test.
mesh_terms: D000328:Adult; D001827:Body Height; D001833:Body Temperature Regulation; D001835:Body Weight; D003971:Diastole; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D007024:Hypotension, Orthostatic / Q000209:etiology*; D008297:Male; D005082:Physical Exertion; D011187:Posture; D011674:Pulse; D013575:Syncope / Q000150:complications; D013599:Systole