title: Heat acclimatization and hydration status of American football players during initial summer workouts.
abstract: This investigation evaluated the new National Collegiate Athletic Association model of heat acclimatization for football players using physiological, psychological, fluid balance, anthropometric, and nutritional variables. Eleven football players (20 +/- 1 year, 1.88 +/- 0.05 m, and 115.36 +/- 18.85 kg) from a Division I football team were observed for the first 8 days of preseason practices. Measurements such as heart rate and gastrointestinal temperature (T(GI)) via telemetric sensor were taken before, 3 times during, and after practice daily. An average 1.39-kg (1.2%) decrease of body mass occurred from prepractice to postpractice (p < 0.01). Consistent with mild body mass losses, urinary indices of hydration status (i.e., color, specific gravity, and osmolality) indicated mild fluid deficits. A significant increase (p < 0.05) from pre- to postpractice was observed in urine color and urine specific gravity, but chronic hypohydration over the 8 days was not noted. The Environmental Symptoms Questionnaire (ESQ) postpractice score was significantly higher (p < 0.05) than the prepractice score was, but averages did not differ across practice days. There was no difference in postpractice T(GI) measurements across days (p < 0.05). Heart rate, T(GI), and ESQ measurements indicated that football players experienced gradual heat acclimatization and enhanced heat tolerance, despite progressive increases of exercise variables, clothing, and environmental stressors.
authors.affiliation: Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Susan W
authors.initials: SW
authors.lastname: Yeargin
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Casa
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Armstrong
authors.forename: Greig
authors.initials: G
authors.lastname: Watson
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Judelson
authors.forename: Eleni
authors.initials: E
authors.lastname: Psathas
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Sparrow
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D015992:Body Mass Index; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology*; D003681:Dehydration / Q000503:physiopathology* / Q000517:prevention & control; D004032:Diet; D005538:Football / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D012621:Seasons; D013046:Specific Gravity; D013334:Students; D013686:Telemetry; D014481:United States; D014495:Universities; D016482:Urinalysis; D014887:Weather