Accession Number : ADA480325

Title :   Effect of Heat Acclimation on Sweat Minerals

Descriptive Note : Journal article

Corporate Author : ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA THERMAL AND MOUNTAIN MEDICINE DIVISION

Personal Author(s) : Chinevere, Troy D ; Kenefick, Robert W ; Cheuvront, Samuel N ; Lukaski, Henry C ; Sawka, Michael N

Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a480325.pdf

Report Date : Dec 2007

Pagination or Media Count : 7

Abstract : Purpose: This study examined the impact of 10 days of exercise-heat acclimation on sweat mineral concentrations. Methods: Eight male subjects walked on a treadmill at 3.5 mph, 4% grade for 100 continuous minutes or until rectal temperature reached 39.5 C on 10 consecutive days in an environmental chamber set at 45 C, 20% relative humidity. Arm sweat samples were collected during the first 30 min of exercise-heat stress on days 1 and 10 using a polyethylene arm glove. Results: Final core temperature and HR values were significantly lower (P 0.05) on day 10 versus day 1. Whole-body sweating rates increased by approximately 6% (P = 0.12). Sweat sodium concentration on day 10 (36.22 + or - 7.22 mM) was significantly lower than day 1 (54.49 + or - 16.18 mM) (P 0.05). Sweat mineral concentrations of calcium (29%), copper (50%), and magnesium (43%) were also significantly lower on day 10 versus day 1 of heat acclimation (P 0.05). A trend for lower sweat iron (75%; P = 0.07) and zinc (23%; P = 0.10) concentrations were observed from day 1 to day 10. The estimated hourly sweat mineral losses (arm concentration x whole-body sweat rate) were reduced for calcium (27%), copper (46%), and magnesium (42%) (P 0.05), but not iron (75%) or zinc (16%) (P 0.05), from day 1 to day 10. Conclusion: Exercise-heat acclimation conserves arm sweat mineral concentrations and possibly whole-body sweat losses of calcium, copper, and magnesium, and may reduce sweat iron and zinc concentrations.

Descriptors :   *MINERALS , *PERSPIRATION , *HEAT ACCLIMATIZATION , REPRINTS , MAGNESIUM , CALCIUM , IRON , EXERCISE(PHYSIOLOGY) , BODY TEMPERATURE , COPPER , ZINC , LOSSES

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE