Does Short-Duration Heat Exposure at a Matched Cardiovascular Intensity Improve Intermittent-Running Performance in a Cool Environment?

作者：Philp Calvin P; Buchheit Martin; Kitic Cecilia M; Minson Christopher T; Fell James W

来源：International Journal of Sports Physiology and Performance, 2017, 12(6): 812-818.

DOI：10.1123/ijspp.2016-0072

• heat acclimation
• football
• plasma volume
• relative-intensity exercise
• V-IFT

Purpose: To investigate whether a 5-d cycling training block in the heat (35 degrees C) in Australian Rules footballers was superior to exercising at the same relative intensity in cool conditions (15 degrees C) for improving intermittent-running performance in a cool environment (<18 degrees C). Methods: Using a parallel-group design, 12 semiprofessional football players performed 5 d of cycling exercise (70% heart-rate reserve [HRR] for 45 min [5 x 50-min sessions in total]) in a hot (HEAT, 35 degrees C +/- 1 degrees C, 56% +/- 9% RH) or cool environment (COOL, 15 degrees C +/- 3 degrees C, 81% +/- 10% RH). A 30-15 Intermittent Fitness Test to assess intermittent running performance (V-IFT) was conducted in a cool environment (17 degrees C +/- 2 degrees C, 58 +/- 5% RH) before and twice after (1 and 3 d) the intervention. Results: There was a likely small increase in V-IFT in each group (HEAT, 0.5 +/- 0.3 km/h, 1.5 +/- 0.8 x smallest worthwhile change [SWC]; COOL, 0.4 +/- 0.4 km/h, 1.6 +/- 1.2 x SWC) 3 d postintervention, with no difference in change between the groups (0.5% +/- 1.9%, 0.4 +/- 1.4 x SWC). Cycle power output during the intervention was almost certainly lower in the HEAT group (HEAT 1.8 +/- 0.2 W/kg vs COOL 2.5 +/- 0.3 W/kg, -21.7 +/- 3.2 x SWC, 100/0/0). Conclusions: When cardiovascular exercise intensity is matched (ie, 70% HRR) between environmental conditions, there is no additional performance benefit from short-duration moderate-intensity heat exposure (5 x 50 min) for semiprofessional footballers exercising in cool conditions. However, the similar positive adaptations may occur in HEAT with 30% lower mechanical load, which may be of interest for load management during intense training or rehabilitation phases.

• 出版日期2017-6