title: Effect of milk protein addition to a carbohydrate-electrolyte rehydration solution ingested after exercise in the heat.
abstract: The present study examined the effects of milk protein on rehydration after exercise in the heat, via the comparison of energy- and electrolyte content-matched carbohydrate and carbohydrate-milk protein solutions. Eight male subjects lost 1·9 (SD 0·2) % of their body mass by intermittent exercise in the heat and rehydrated with 150% of their body mass loss with either a 65 g/l carbohydrate solution (trial C) or a 40 g/l carbohydrate, 25 g/l milk protein solution (trial CP). Urine samples were collected before and after exercise and for 4 h after rehydration. Total cumulative urine output after rehydration was greater for trial C (1212 (SD 310) ml) than for trial CP (931 (SD 254) ml) (P < 0·05), and total fluid retention over the study was greater after ingestion of drink CP (55 (SD 12) %) than that after ingestion of drink C (43 (SD 15) %) (P < 0·05). At the end of the study period, whole body net fluid balance (P < 0·05) was less negative for trial CP (-0·26 (SD 0·27) litres) than for trial C (-0·52 (SD 0·30) litres), and although net negative for both the trials, it was only significantly negative after ingestion of drink C (P < 0·05). The results of the present study suggest that when matched for energy density and fat content, as well as for Na and K concentration, and when ingested after exercise-induced dehydration, a carbohydrate-milk protein solution is better retained than a carbohydrate solution. These results suggest that gram-for-gram, milk protein is more effective at augmenting fluid retention than carbohydrate.
authors.affiliation: School of Science and Technology, Erasmus Darwin Building, Nottingham Trent University, Clifton Lane, Nottingham, Nottinghamshire NG11 8NS, UK. lewis.james@ntu.ac.uk
authors.forename: Lewis J
authors.initials: LJ
authors.lastname: James
authors.forename: David
authors.initials: D
authors.lastname: Clayton
authors.forename: Gethin H
authors.initials: GH
authors.lastname: Evans
mesh_terms: D001835:Body Weight; D002241:Carbohydrates / Q000008:administration & dosage / Q000652:urine; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004573:Electrolytes / Q000008:administration & dosage; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008894:Milk Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D015532:Rehydration Solutions / Q000008:administration & dosage / Q000494:pharmacology*; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D002241:Carbohydrates; D004573:Electrolytes; D008894:Milk Proteins; D015532:Rehydration Solutions