title: Sweat rates and fluid turnover in professional football players: a comparison of National Football League linemen and backs.
abstract: BACKGROUND
  Many National Football League (NFL) teams practice 2 times per day over consecutive days in a hot and humid environment. Large body surface area (BSA) and use of protective equipment result in high sweat rates and total sweat loss in these football players.
  
  
  OBJECTIVE
  To compare sweat rate, sweat loss, fluid consumption, and weight loss between NFL linemen and backs during preseason practices.
  
  
  METHODS
  Between-groups design.
  
  
  METHODS
  Preseason training camp with wet bulb globe temperature between 19 degrees C and 25 degrees C.
  
  
  METHODS
  Eight linemen and 4 backs and receivers participated.
  
  
  METHODS
  Data were collected during both practice sessions on 2 separate days during the first week of August. Sweat rate was calculated as change in mass adjusted for all fluids consumed between prepractice and postpractice body mass measurements and the urine produced during practice divided by the length of the practice session. Gross daily sweat losses also were calculated.
  
  
  RESULTS
  Height, mass, and BSA were higher in linemen than in backs. Sweat rate was also higher in linemen (2385 +/- 520 mL/h) than in backs (1410 +/- 660 mL/h, P < .001), as was the total volume of sweat lost during both practices in 1 day (6870 +/- 1034 mL/d versus 4110 +/- 2287 mL/d, P = .014). Compared with backs, linemen consumed more fluids during practice (2030 +/- 849 mL versus 1179 +/- 753 mL, P = .025) but produced less urine (53 +/- 73 mL versus 163 +/- 141 mL, P = .018). There was no difference in postpractice weight loss (linemen = -1.15 +/- 0.83%, backs = -1.06 +/- 0.76%).
  
  
  CONCLUSIONS
  Linemen sweated at higher rates, lost larger volumes of sweat, consumed more fluids, and produced less urine during practice compared with the physically smaller backs, but they did not lose a greater percentage of body weight. Sodium losses could be considerable in NFL players during the preseason because of high daily sweat losses in backs and in linemen.
authors.affiliation: The HEAT Institute of West Chester University, West Chester, PA 19383, USA. sfowkesgod@wcupa.edu
authors.forename: Sandra Fowkes
authors.initials: SF
authors.lastname: Godek
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Bartolozzi
authors.forename: Richard
authors.initials: R
authors.lastname: Burkholder
authors.forename: Eric
authors.initials: E
authors.lastname: Sugarman
authors.forename: Chris
authors.initials: C
authors.lastname: Peduzzi
mesh_terms: D000328:Adult; D001833:Body Temperature Regulation; D003681:Dehydration / Q000209:etiology* / Q000503:physiopathology; D005334:Fever; D005440:Fluid Therapy; D005538:Football / Q000502:physiology*; D006305:Health Status Indicators; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008297:Male; D012307:Risk Factors; D012964:Sodium / Q000502:physiology; D013546:Sweating / Q000502:physiology*
chemical_list: D012964:Sodium