Year: 1990
Type: dissertation
Abstract: The activity of baroreceptors on convective and evaporative heat loss was investigated by requesting heat stressed subjects to recover idle or performing static exercise in either the supine or the upright posture. Forearm skin blood flow (AF&BF, ml. 1 00g' -mid) fell more (P10.04) in upright than in supine recovery. S,r (mg-se(rl*mz) changed less over a given range of Tes (OC) and the point of its extinction was delayed (P1O.OO1) in the upright compared with the supine position. The forearm skin blood flow (AF*BF) was higher (PS0.02) during idle recovery than during static exercise recovery at any given Tes. The subjects sweated considerably more (P10.03) during the last 24 minutes of recovery with static exercise than while idle. For a given a,,, the Te,-Swr relationship showed a trend (PS0.05) of a higher slope during static exercise than while idle, whereas the cessation of the sweating response was similar. A lower ED1 (ml-kg,P~0.05) and greater MAP (rnm Hg, P10.02) and a concominant lower FskBF and Swr for a range of Ta measures in the upright versus the supine recovery position suggests baroreceptors may modify the therrnoregulatory response. The lower F&BF during recovery in the upright than in the supine position may be attributed to a skin vasoconstrictive reflex originating from the cardiopulmonary baroreceptors. Cardiopulmonary baroreflex action might also have provoked the Swr changes observed between the upright and supine position. Compared with the idle condition, there was a tendency for S,r to be higher at a given T, in the static exercise condition. Because it was found that the baroreceptors were unloaded in the upright compared with supine static exercise condition whereas Swr was similar, it may be suggested that the higher Swr during static exercise than during the idle recovery was not
Source: Summit (Simon Fraser University)
Author: Niolaos D. Geladas
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2154576866