title: The influence of hot humid and hot dry environments on intermittent-sprint exercise performance.
abstract: OBJECTIVE
  To examine the effect of a hot humid (HH) compared with a hot dry (HD) environment, matched for heat stress, on intermittent-sprint performance. In comparison with HD, HH environments compromise evaporative heat loss and decrease exercise tolerance. It was hypothesized that HH would produce greater physiological strain and reduce intermittent-sprint exercise performance compared with HD.
  
  
  METHODS
  Eleven male team-sport players completed the cycling intermittent-sprint protocol (CISP) in 3 conditions, temperate (TEMP; 21.2°C ± 1.3°C, 48.6% ± 8.4% relative humidity [rh]), HH (33.7°C ± 0.5°C, 78.2% ± 2.3% rh), and HD (40.2°C ± 0.2°C, 33.1% ± 4.9% rh), with both heat conditions matched for heat stress.
  
  
  RESULTS
  All participants completed the CISP in TEMP, but 3 failed to completed the full protocol of 20 sprints in HH and HD. Peak power output declined in all conditions (P < .05) but was not different between any condition (sprints 1-14 [N = 11]: HH 1073 ± 150 W, HD 1104 ± 127 W, TEMP, 1074± 134; sprints 15-20 [N = 8]: HH 954 ± 114 W, HD 997 ± 115 W, TEMP 993 ± 94; P > .05). Physiological strain was not significantly different in HH compared with HD, but HH was higher than TEMP (P < .05).
  
  
  CONCLUSIONS
  Intermittent-sprint exercise performance of 40 min duration is impaired, but it is not different in HH and HD environments matched for heat stress despite evidence of a trend toward greater physiological strain in an HH environment.
authors: School of Sport and Service Management, University of Brighton, Eastbourne, UK.
authors: Mark
authors: M
authors: Hayes
authors: Paul C
authors: PC
authors: Castle
authors: Emma Z
authors: EZ
authors: Ross
authors: Neil S
authors: NS
authors: Maxwell
mesh_terms: D000328:Adult; D054874:Athletic Performance; D001642:Bicycling; D015415:Biomarkers / Q000097:blood; D001833:Body Temperature Regulation; D004739:England; D004777:Environment; D005080:Exercise Test; D006339:Heart Rate; D018869:Heat-Shock Response; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D019344:Lactic Acid / Q000097:blood; D008297:Male; D053580:Muscle Strength; D010101:Oxygen Consumption; D010465:Perception; D010807:Physical Endurance; D012881:Skin Temperature; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D019344:Lactic Acid