Effects of heat exposure and 3% dehydration achieved via hot water immersion on repeated cycle sprint performance.
This study examined effects of heat exposure with and without dehydration on repeated anaerobic cycling. Males (n = 10) completed 3 trials: control (CT), water-bath heat exposure (∼39°C) to 3% dehydration (with fluid replacement) (HE), and similar heat exposure to 3% dehydration (DEHY). Hematocrit increased significantly from pre to postheat immersion in both HE and DEHY. Participants performed 6 × 15s cycle sprints (30s active recovery). Mean Power (MP) was significantly lower vs. CT (596 ± 66 W) for DEHY (569 ± 72 W), and the difference approached significance for HE (582 ± 76 W, p = 0.07). Peak Power (PP) was significantly lower vs. CT (900 ± 117 W) for HE (870 ± 128 W) and approached significance for DEHY (857 ± 145 W, p = 0.07). Postsprint ratings of perceived exertion was higher during DEHY (6.4 ± 2.0) and HE (6.3 ± 1.6) than CT (5.7 ± 2.1). Combined heat and dehydration impaired MP and PP (decrements greatest in later bouts) with HE performance intermediate to CT and DEHY.
Health Physical Education and Recreation, Missouri Western State University, St Joseph, Missouri, USA. jkraft@missouriwestern.edu
Justin A
JA
Kraft
James M
JM
Green
Phillip A
PA
Bishop
Mark T
MT
Richardson
Yasmin H
YH
Neggers
James D
JD
Leeper
D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D004326:Drinking; D006339:Heart Rate / Q000502:physiology; D018869:Heat-Shock Response; D006400:Hematocrit; D006358:Hot Temperature; D006801:Humans; D007101:Immersion; D008297:Male; D055815:Young Adult