Circulatory changes in cold-acclimation and cold stress.
1. The cardiovascular changes of conscious cold-acclimated (CA) and warm-acclimated (WA) rats during exposure to 5 degrees C or 28 degrees C were studied. 2. The cardiac output, heart rate and stroke volume of Ca rats exposed to 5 degrees C and of WA rats during cold stress were significantly greater, and their calculated total peripheral resistance significantly less than those of WA rats ats exposed to 28 degrees C. These results show that circulatory changes participate in cold acclimation and cold stress. The circulatory changes in the two conditions were compared and the mechanism of the observed differences were discussed. 3. CA rats exposed to 28 degrees C showed a striking decrease of oxygen consumption and arterio-venous O2 difference, but significant circulatory changes were decreased heart rate and cardiac index only, indicating that the response was mainly metabolic.
D000064:Acclimatization; D000818:Animals; D003080:Cold Temperature; D006439:Hemodynamics; D008297:Male; D010101:Oxygen Consumption; D051381:Rats; D013312:Stress, Physiological / Q000378:metabolism / Q000503:physiopathology*