Hypohydration and Acclimation: Effects on Hormone Responses to Excercise/Heat Stress.
Abstract
This study was designed to assess the effects of hypohydration (-5% body weight) and heat acclimation on plasma cortisol and growth hormone responses to exercise (1.34 m/sec -1) in a thermoneutral (20 C, 40% rh), hot-wet (35 C, 79% rh), or hot-dry (49 degrees C, 20% rh) environment. Exercise in a thermoneutral environment while euhydrated resulted in significant (p<.05) decrements in plasma cortisol (PC); however, when hypohydrated, PC levels were significantly (p<.02) elevated. Acclimation attenuated the PC elevations elicited by hypohydration. Hypohydration also effected significant (p<.02) increases in growth hormone (GH) in the thermoneutral environment. Exercise in a hot-wet or hot-dry environment resulted in significant (p<.05) increments in both hormones when hypohydrated; these effects were, in several instances, attenuated (p<.05) by acclimation, particularly in the hot-wet environment. We concluded that the PC and GH responses were amplified when subjects were hypohydrated and, in several instances, these responses were attenuated by heat acclimation. Additionally, our data indicated that gender does not affect the direction or intensity of these hormonal responses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 15, 1983
- Accession Number
- ADA127855
Entities
People
- Kent B. Pandolf
- Michael N. Sawka
- Ralph P. Francesconi
Organizations
- United States Army Research Institute of Environmental Medicine