Work Enhancement and Thermal Changes during Intermittent Work in Cool Water after Carbohydrate Loading.

Abstract

(U) We evaluated the effect of carbohydrate loading (TEST) vs control diet (CON) on the thermal status and the ability of 8 U.S. Navy divers to perform intermittent leg exercise at 80% max Oxygen 2 consumption during head-out immersion in 25 deg C water. Each subject was tested once after 3 days of the TEST diet (600 grams carbohydrate/day and once after 3 days of CON diet (less than 300 g carbohydrate/d). The TEST diet included 200-400 grams of glucose polymer solution (GPS). Both diets were nutritionally complete and provided 3000 Kcal/d. A pattern of 10 min rest/20 min work was repeated until the diver could no longer complete a 20-min work session or until 8 sessions had been completed. Divers completed more work after TEST than CON. Four completed all 8 work sessions after both diets; 3 completed all sessions after TEST, but not CON; one completed 7 sessions after TEST and 6 after CON. Differences between diets for O2 consumption, CO2 production, and minute ventilation were not significant. Keyword: Exercise endurance, Immersion, Stress physiology work enhancement thermal changes; Diet, Biochemistry, Temperature, Heat flux.