Effects of dietary sodium on body and muscle potassium content during heat acclimation.
It has been suggested that renal conversion of sodium (Na+) during training in hot environments results in potassium (K+) deficiencies. This investigation examined the influence of two levels of dietary Na+ intake (399 vs 98 mmol X d-1) on intramuscular, urinary, sweat, and whole body K+ homeostasis. Nine unacclimated, untrained males underwent heat acclimation during two 8 day dietary-exercise regimens (40.1 +/- 0.1 degrees C, 23.5 +/- 0.4% RH). Both diets resulted in depressed urinary K+ excretion. Sweat K+ and muscle K+ concentrations were not altered by diets or acclimation. The whole body stores of Na+ increased 31.1% (+916.8 mmol) during the high Na+ diet and decreased 7.8% (-230.4 mmol) during the low Na+ diet; whole body stores of K+ increased 4.1% (+137.6 mmol) during the high Na+ diet and increased 3.4% (+113.6 mmol) during the low Na+ diet. This dietary-acclimation protocol did not result in whole-body or intramuscular K+ deficits and offers no evidence to support previous claims that dietary sodium levels affect K+ balance.
D000064:Acclimatization; D000328:Adult; D001831:Body Temperature / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004032:Diet; D004231:Diuresis / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006358:Hot Temperature; D006801:Humans; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D005082:Physical Exertion; D010953:Plasma Volume / Q000187:drug effects; D011188:Potassium / Q000378:metabolism* / Q000652:urine; D012964:Sodium / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D013542:Sweat / Q000378:metabolism; D013546:Sweating / Q000187:drug effects
D012964:Sodium; D011188:Potassium