title: Effect of dilute CHO beverages on performance in cool and warm environments.
abstract: OBJECTIVE
  The efficacy of drinks containing low concentrations of CHO (2%-6%) on physical performance in cool and warm environments was evaluated.
  
  
  METHODS
  In two separate but related studies, 24 healthy males completed a familiarization trial and four trials to volitional exhaustion (TTE) at 70% VO2max in cool conditions (10°C, n = 12) or 60% VO2max in a warm environment (30°C, n = 12). Subjects ingested 0%, 2%, 4%, or 6% CHO solutions (sucrose, glucose, and fructose in a ratio of 50:25:25) immediately before exercise and every 10 min during exercise.
  
  
  RESULTS
  TTE in 10°C was 102.6 ± 33.9, 109.2 ± 33.9, 121.0 ± 25.7, and 122.4 ± 29.9 min in the 0%, 2%, 4%, and 6% trials, respectively (P = 0.012). Compared with the 0% trial, TTE was longer in the 4% (P = 0.032, effect size (ES) = 0.72) and 6% (P = 0.044, ES = 0.66) trials. In addition, TTE was longer in the 6% trial than in the 2% trial (P = 0.025). TTE was also significantly influenced by drink CHO content at 30°C (0% = 94.5 ± 24.5 min, 2% = 104.1 ± 20.1 min, 4% = 105.5 ± 26.7 min, 6% = 112.0 ± 28.7 min; P = 0.046). No differences in TTE were apparent between the 0% and the 2% or 4% trials, but TTE was longer in the 6% trial compared with the placebo (P = 0.045, ES = 0.62). HR, core temperature, or rates of substrate oxidation were not affected by drink CHO content.
  
  
  CONCLUSIONS
  These results demonstrate significant improvements in exercise capacity over the placebo trial when 4% and 6% CHO solutions were ingested at 10°C and a 6% CHO drink was ingested at 30°C.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom.
authors.forename: Phillip
authors.initials: P
authors.lastname: Watson
authors.forename: Susan M
authors.initials: SM
authors.lastname: Shirreffs
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Maughan
mesh_terms: D000328:Adult; D001628:Beverages; D003080:Cold Temperature; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D017079:Exercise Tolerance / Q000187:drug effects* / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates