title: Daily fluid turnover during preseason training in U.S. college football.
abstract: The authors measured 24-h fluid-turnover (FTO) rate during 6 d of preseason training in U.S. college football players. Players, training (T, n = 9, full gear and contact drills) and reference (R, n = 4, conditioning without gear or contact), ingested a deuterium oxide (D(2)O) dose and provided urine samples every 24 h for analysis of D(2)O. During one approximately 2.3-h practice (wet-bulb globe temperature 24.6 degrees C), body-mass change, urine production, and voluntary fluid intake were measured to calculate gross sweat loss (GSL). Average FTO was 10.3 +/- 2.2 L/d for T and 7.0 +/- 1.0 L/d for R. GSL was 3.4 +/- 1.5 L for T and 1.7 +/- 1.3 for R (P > 0.05). By Day 6, body mass decreased significantly in T (-2.4 +/- 1.3 kg, P < 0.05) but not in R (0.38 +/- 0.95 kg). With preseason training under moderate environmental stress, football players had high FTO and sweat rates, which might have contributed to a loss of body mass during preseason football training.
authors.affiliation: Gatorade Sports Science Institute, Barrington, IL 60010, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Stofan
authors.forename: Kris L
authors.initials: KL
authors.lastname: Osterberg
authors.forename: Craig A
authors.initials: CA
authors.lastname: Horswill
authors.forename: Magie
authors.initials: M
authors.lastname: Lacambra
authors.forename: E Randy
authors.initials: ER
authors.lastname: Eichner
authors.forename: Scott A
authors.initials: SA
authors.lastname: Anderson
authors.forename: Robert
authors.initials: R
authors.lastname: Murray
mesh_terms: D000328:Adult; D001834:Body Water / Q000378:metabolism*; D001835:Body Weight / Q000502:physiology*; D017666:Deuterium Oxide / Q000652:urine; D004327:Drinking Behavior; D005538:Football / Q000502:physiology*; D006801:Humans; D008297:Male; D012621:Seasons; D013546:Sweating / Q000502:physiology*; D016482:Urinalysis
chemical_list: D017666:Deuterium Oxide