title: Separate and combined effects of airflow and rehydration during exercise in the heat.
abstract: OBJECTIVE
  To determine whether airflow is required to obtain the beneficial effects of rehydration (thermoregulatory and cardiovascular) during exercise in dry heat.
  
  
  METHODS
  Ten moderately trained (VO2max = 55 +/- 8 mL.kg(-1).min(-1)) heat acclimated males pedaled for 60 min at 60% VO2max in a hot-dry environment (36 +/- 1 degrees C; 29 +/- 2% relative humidity) on four different occasions: 1) without rehydration or forced airflow (control trial; CON); 2) rehydrating 100% of sweat losses by ingestion of a 6% carbohydrate-electrolyte solution (rehydration trial; REH); 3) receiving airflow at a velocity of 2.55 m.s(-1) (wind trial; WIND); and 4) combining airflow and rehydration (W + R).
  
  
  RESULTS
  Without airflow, rehydration alone (REH) did not lower rectal temperature below CON (39.0 +/- 0.1 vs 39.1 +/- 0.1 degrees C at 60 min; respectively). However, with airflow, rehydration reduced final rectal temperature (38.8 +/- 0.1 vs 38.5 +/- 0.1 degrees C; P < 0.05; WIND vs W + R). In the trials with wind (WIND and W + R), skin temperature was reduced by about 0.6 degrees C (P < 0.05), and heart rate drift was prevented. In the trials with rehydration (REH and W + R trials), cardiac output (CO2-rebreathing technique) was maintained higher than CON (16.5 +/- 0.4 and 17.0 +/- 0.7 vs 15.4 +/- 0.4 L.min(-1), respectively; P < 0.05).
  
  
  CONCLUSIONS
  When exercising in a hot-dry environment, airflow is required for rehydration to improve thermoregulation and cardiovascular function.
authors.affiliation: University of Castilla-La Mancha, Exercise Physiology Laboratory, Toledo, Spain. Ricardo.Mora@uclm.es
authors.forename: Ricardo
authors.initials: R
authors.lastname: Mora-Rodriguez
authors.forename: Juan
authors.initials: J
authors.lastname: Del Coso
authors.forename: Roberto
authors.initials: R
authors.lastname: Aguado-Jimenez
authors.forename: Emma
authors.initials: E
authors.lastname: Estevez
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology; D002302:Cardiac Output; D005440:Fluid Therapy; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D010101:Oxygen Consumption / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology*; D012867:Skin / Q000098:blood supply; D013030:Spain; D013542:Sweat / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000502:physiology