title: The temperature of water ingested ad libitum does not influence performance during a 40-km self-paced cycling trial in the heat.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the effects of the temperature of ingested water on performance during a 40-km self-paced cycling trial in the heat (35º C and 60% relative humidity).
  
  
  METHODS
  The study was randomized, counterbalanced, crossover and single-blinded. Ten well-trained male cycling athletes (cyclists, mountain bikers or triathletes) who were non-acclimatized to heat were subjected to four experimental situations divided into two sets. In the first set, the participants performed two trials, during which they were given either cold (10º C) or warm water (37º C) ad libitum. In these situations, the volume and timing of the water ingestion (when each bolus was ingested) were recorded and replicated in the second set, but the water temperature was reversed.
  
  
  RESULTS
  The performance times were unaffected by the water intake volume (P=0.425), but the water at a temperature of 37º C tended to induce lower performance times (P=0.078) during the trials (AL10=93.0±3.5 min; AL37=94.4±4.1 min; SC10=93.4±4.0; SC37=97.4±4.3 min). The water intake was greater when the water was cold (P<0.05), but the temperature did not affect the heat storage rate, rectal temperature, mean skin temperature, heart rate, blood glucose level, sweat loss, sweat rate, perceived exertion rate or plasma volume changes. However, a significant reduction in the plasma volume change from pre- to postexercise was observed (P<0.01).
  
  
  CONCLUSIONS
  The performance, thermoregulatory, cardiovascular and metabolic responses during a 40-km self-paced cycling trial in the heat were unaffected by different water temperatures.
authors.affiliation: School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil - moises.carvalho@uemg.br.
authors.forename: M V
authors.initials: MV
authors.lastname: De Carvalho
authors.forename: M T
authors.initials: MT
authors.lastname: De Andrade
authors.forename: G P
authors.initials: GP
authors.lastname: Ramos
authors.forename: A
authors.initials: A
authors.lastname: Maia-Lima
authors.forename: E R
authors.initials: ER
authors.lastname: Pereira
authors.forename: T T
authors.initials: TT
authors.lastname: Mendes
authors.forename: J C
authors.initials: JC
authors.lastname: Marins
authors.forename: F T
authors.initials: FT
authors.lastname: Amorim
authors.forename: E
authors.initials: E
authors.lastname: Silami-Garcia
mesh_terms: D000328:Adult; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D018592:Cross-Over Studies; D004326:Drinking / Q000502:physiology*; D006801:Humans; D008297:Male; D013696:Temperature; D055815:Young Adult