Effect of water and electrolyte replacement during exercise in the heat on biochemical indices of stress and performance
Francis, K.T.
Aviation Space and Environmental Medicine 50(2): 115-119
1979
ISSN/ISBN: 0095-6562 PMID: 444171 Document Number: 150938
Healthy young men (8) exercised on alternate days in a warm, humid environment (32.degree. C, 65.degree. RH for 2 h while receiving a water supplement (WS), glucose-electrolyte solution (ES), or no fluid supplement (NS). The average weight loss after 2 h of exercise and NS was 2.44 kg with a resultant plasma volume decrease of 17%. This acute period of exercise with no fluid replacement elicited significant increments in serum levels of cortisol, dopamine-B-hydroxylase and uric acid. Alternatively, exercise in the heat for the same duration with water or electrolyte supplement failed to effect significant alterations in any of these physical or biochemical factors compared to pre-exercise levels. Heart rates under the influence of heat stress and exercise with NS averaged 18% higher at each time period studied compared with WS or ES.