Muscle Water and Electrolyte Balance During Chronic Exposure and Work in the Heat,
Abstract
In an effort to assess the effect of acute exercise and heat acclimation on muscle metabolism and electrolyte balance, three projects were conducted. The first investigation (Project I) was reported earlier (Annual Report, April 30, 1984) and demonstrated that diets high (399 mEq Na+/day) and low (98 mEq Na+/day) in sodium did not alter the muscle potassium content. The low sodium diet, however, appeared to lessen the subject's rate of heat acclimation. Project II and III (reported here) examined the effect of heat acclimation on aerobic exercise tolerance in the heat and on subsequent sprint exercixe performance. These studies indicate that heat acclimation produces a shift in fuel selection during submaximal exercise in the heat, with a 47-48% reduction in glycogen use by the vastus lateralis muscle. Leg blood flow studies reveal that heat acclimation does not alter the uptake or release of glucose, free fatty acids or glycerol. Although respiratory exchange ratios and lactage efflux from the muscle revealed a small shift to greater lipid oxidation, these small changes can not explain the sparing of muscle glycogen seen in these studies.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 1985
- Accession Number
- ADA177578
Entities
People
- David L. Costill
- Douglas S. King
- Lawrence E. Armstrong
- William J. Fink
Organizations
- Ball State University