title: Thermoregulation and stress hormone recovery after exercise dehydration: comparison of rehydration methods.
abstract: BACKGROUND
  Athletic trainers recommend and use a multitude of rehydration (REHY) methods with their patients. The REHY modality that most effectively facilitates recovery is unknown.
  
  
  OBJECTIVE
  To compare 5 common REHY methods for thermoregulatory and stress hormone recovery after exercise dehydration (EXDE) in trained participants.
  
  
  METHODS
  Randomized, cross-over, controlled study.
  
  
  METHODS
  Twelve physically active, non-heat-acclimatized men (age = 23 ± 4 years, height = 180 ± 6 cm, mass = 81.3 ± 3.7 kg, VO2max = 56.9 ± 4.4 mL·min(-1)·kg(-1), body fat = 7.9% ± 3%) participated.
  
  
  METHODS
  Participants completed 20-hour fluid restriction and 2-hour EXDE; they then received no fluid (NF) or REHY (half-normal saline) via ad libitum (AL), oral (OR), intravenous (IV), or combination IV and OR (IV + OR) routes for 30 minutes; and then were observed for another 30 minutes.
  
  
  METHODS
  Body mass, rectal temperature, 4-site mean weighted skin temperature, plasma stress hormone concentrations, and environmental symptoms questionnaire (ESQ) score.
  
  
  RESULTS
  Participants were hypohydrated (body mass -4.23% ± 0.22%) post-EXDE. Rectal temperature for the NF group was significantly greater than for the IV group (P = .023) at 30 minutes after beginning REHY (REHY30) and greater than OR, IV, and IV + OR (P ≤ .009) but not AL (P = .068) at REHY60. Mean weighted skin temperature during AL was less than during IV + OR at REHY5 (P = .019). The AL participants demonstrated increased plasma cortisol concentrations compared with IV + OR, independent of time (P = .015). No differences existed between catecholamine concentrations across treatments (P > .05). The ESQ score was increased at REHY60 for NF, AL, OR, and IV (P < .05) but not for IV + OR (P = .217). The NF ESQ score was greater than that of IV + OR at REHY60 (P = .012).
  
  
  CONCLUSIONS
  Combination IV + OR REHY reduced body temperature to a greater degree than OR and AL REHY when compared with NF. Future studies addressing clinical implications are needed.
authors.affiliation: Athletic Training Education Program, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville.
authors.forename: Brendon P
authors.initials: BP
authors.lastname: McDermott
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Casa
authors.forename: Elaine
authors.initials: E
authors.lastname: Lee
authors.forename: Linda
authors.initials: L
authors.lastname: Yamamoto
authors.forename: Kathleen
authors.initials: K
authors.lastname: Beasley
authors.forename: Holly
authors.initials: H
authors.lastname: Emmanuel
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Anderson
authors.forename: Linda
authors.initials: L
authors.lastname: Pescatello
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Armstrong
authors.forename: Carl
authors.initials: C
authors.lastname: Maresh
mesh_terms: D061605:Administration, Intravenous; D000284:Administration, Oral; D000328:Adult; D018592:Cross-Over Studies; D003681:Dehydration; D015444:Exercise / Q000502:physiology*; D005440:Fluid Therapy / Q000379:methods*; D018882:Heat Stress Disorders; D006801:Humans; D008297:Male; D012881:Skin Temperature / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*; D013542:Sweat; D055815:Young Adult