title: Effect of thermal state and thermal comfort on cycling performance in the heat.
abstract: OBJECTIVE
  To determine the effect of thermal state and thermal comfort on cycling performance in the heat.
  
  
  METHODS
  Seven well-trained male triathletes completed 3 performance trials consisting of 60 min cycling at a fixed rating of perceived exertion (14) followed immediately by a 20-km time trial in hot (30°C) and humid (80% relative humidity) conditions. In a randomized order, cyclists either drank ambient-temperature (30°C) fluid ad libitum during exercise (CON), drank ice slurry (-1°C) ad libitum during exercise (ICE), or precooled with iced towels and ice slurry ingestion (15 g/kg) before drinking ice slurry ad libitum during exercise (PC+ICE). Power output, rectal temperature, and ratings of thermal comfort were measured.
  
  
  RESULTS
  Overall mean power output was possibly higher in ICE (+1.4%±1.8% [90% confidence limit]; 0.4> smallest worthwhile change [SWC]) and likely higher PC+ICE (+2.5%±1.9%; 1.5>SWC) than in CON; however, no substantial differences were shown between PC+ICE and ICE (unclear). Time-trial performance was likely enhanced in ICE compared with CON (+2.4%±2.7%; 1.4>SWC) and PC+ICE (+2.9%±3.2%; 1.9>SWC). Differences in mean rectal temperature during exercise were unclear between trials. Ratings of thermal comfort were likely and very likely lower during exercise in ICE and PC+ICE, respectively, than in CON.
  
  
  CONCLUSIONS
  While PC+ICE had a stronger effect on mean power output compared with CON than ICE did, the ICE strategy enhanced late-stage time-trial performance the most. Findings suggest that thermal comfort may be as important as thermal state for maximizing performance in the heat.
authors.affiliation: MOVE Research Inst Amsterdam, VU University, Amsterdam, The Netherlands.
authors.forename: Emiel
authors.initials: E
authors.lastname: Schulze
authors.forename: Hein A M
authors.initials: HA
authors.lastname: Daanen
authors.forename: Koen
authors.initials: K
authors.lastname: Levels
authors.forename: Julia R
authors.initials: JR
authors.lastname: Casadio
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Plews
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Kilding
authors.forename: Rodney
authors.initials: R
authors.lastname: Siegel
authors.forename: Paul B
authors.initials: PB
authors.lastname: Laursen
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D005082:Physical Exertion / Q000502:physiology*