HYPOHYDRATION AND ACCLIMATION - EFFECTS ON HORMONE RESPONSES TO EXERCISE HEAT-STRESS

  • 1 January 1984
    • journal article
    • research article
    • Vol. 55  (5) , 365-369
Abstract
A study was designed to assess the effects of hypohydration (-5% body weight) and heat acclimation on plasma cortisol (PC) and growth hormone (GH) responses to exercise (1.34 m .cntdot. s-1) in a hot-wet (35.degree. C, 79% rh [relative humidity]) or hot-dry (49.degree. C, 20% rh) environment. Preacclimation, hypohydration in both the hot-wet and hot-dry environments resulted in significant (P < 0.05) increments in PC levels durng the 4th exercise interval. Acclimation had no effects on PC levels in the euhydrated condition, but in the hot-wet environment there did occur an attenuation of the PC response when hypohydrated. Preacclimation exercise in either the hot-wet or hot-dry environment resulted in significant (P < 0.05) increments in GH when euhydrated. While the effects of acclimation were inconsistent, hypohydration generally resulted in elevated levels of GH compared to euhydration. Hypohydration to -5% of body weight generally elicited elevations in circulation levels of stress hormones, and acclimation did not effect consistent decrements in these responses.