Effects of Dietary Sodium on Muscle Water and Electrolytes during Heat Acclimatization.
Abstract
In an effort to assess the influence of daily sodium intake on muscle water and electrolytes during eight, successive days of exercise and heat exposure (90min/day; 40.1 C; 23.5% R.H.; 44-50% Vo2 max), nine men were studied under two dietary sodium (Na+) regimens (399 and 98 mEq Na+/day). Both the 399 mEq Na+ (HI) and 98 mEq Na+ (LO) diets contained 80 mEq potassium (K+) per day. The LO treatment resulted in higher heart rates, higher rectal temperatures, and a smaller plasma volume expansion than during the HI regimen. Though plasma K+ concentration was unchanged throughout both treatments, the plasma K+, Na+ and C1- content increased in proportion to the increase in plasma volume. Muscle water, Na+, and C1- contents were significantly increased (P<.05) were found between the two Na+ diets. Muscle K+, on the other hand, remained unaffected by either the days of heat-exercise stress or the HI-LO diets. Although the LO diet appeared to lessen the subjects' acclimatization to the heat, neither diet affected the body K+ content, nor did they effect the excretion of K+ in urine or sweat.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1984
- Accession Number
- ADA172714
Entities
People
- David L. Costill
- Larry Armstrong
Organizations
- Ball State University