EFFECTS OF HEAT EXPOSURE AND 3% DEHYDRATION ACHIEVED VIA HOT WATER IMMERSION ON REPEATED CYCLE SPRINT PERFORMANCE

Kraft, JA, Green, JM, Bishop, PA, Richardson, MT, Neggers, YH, and Leeper, JD. Effects of heat exposure and 3% dehydration achieved via hot water immersion on repeated cycle sprint performance. J Strength Cond Res 25(3): 778-786, 2011-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 (similar to 39 degrees 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 x 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 6 117 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.