title: Fluid intake during an ultramarathon running race: relationship to plasma volume and serum sodium and potassium.
abstract: To assess the relationship between self-selected fluid intake patterns and changes in plasma volume and serum electrolytes during prolonged exercise, five men completed ultramarathon runs ranging from 50 to 100 km. There was a significant relationship between fluid intake and plasma volume changes but no changes occurred in either serum sodium or potassium. Subjects who ingested the most fluid during the race had a modest hemodilution without any changes in serum or potassium. This response may have been influenced by the consumption of beverages containing osmotically active solutes such as sodium and glucose.
authors.affiliation: Northeastern Illinois University, Human Performance Laboratory, Chicago.
authors.forename: L A
authors.initials: LA
authors.lastname: Kaminsky
authors.forename: G L
authors.initials: GL
authors.lastname: Paul
mesh_terms: D015444:Exercise; D005440:Fluid Therapy; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010953:Plasma Volume; D011188:Potassium / Q000097:blood*; D012420:Running; D012964:Sodium / Q000097:blood*
chemical_list: D012964:Sodium; D011188:Potassium