Author(s): PRADO, L., MAIA-LIMA, A., GORDON, D., MERZBACH, V., Institution: FEDERAL UNIVERSITY OF MINAS GERAIS, Country: BRAZIL, Abstract-ID: 2465

INTRODUCTION:
Physical performance during prolonged exercise performed in hot environments tends to be reduced when compared to those carried out in temperate environments. Several strategies have been proposed in an attempt to mitigate the harmful effects of hot environmental conditions on physical performance, and one of the most popular among them is pre-exercise body cooling. However, there is no consensus on which are the main mechanisms involved in its already well-established ergogenic effect.
METHODS:
This study examined the effects of pre-cooling on physical performance, VO2PEAK, %VO2PEAK utilization, and the VO2 kinetics during a cycling exercise performed in a hot environment. Four men and four women cycling athletes (age 39.75 ± 10.25 years, VO2MAX 52.39 ± 8.74 ml.km-1 .min-1, body mass 65.66 ± 6.37 kg, 16.77 ± 6.86% body fat) volunteered for this study. The participants performed 03 exercise trials – an exercise bout in a temperate environment (20° C, 41% RH; TEMP), an exercise bout in a hot environment (34° C, 60% RH; HOT), and an exercise bout in a hot environment preceded by a precooling intervention through full-body water immersion (PREC). Each exercise trial was composed of 04 sets of cycling separated by a 05-minute rest interval. Each set consisted of 06 minutes of fixed-intensity exercise in a moderate domain, 09 min of self-paced exercise, and 1.5 minutes of performing in the same peak power output that was recorded in the previous VO2max testing.
RESULTS:
Precooling attenuated the decrease in distance covered observed in the HOT condition when compared to TEMP. This physical performance improvement in the PREC condition was associated with prevention in the VO2PEAK reduction seen in the HOT condition, the lower heart rate values observed during the moderate intensity phase, and lower core temperature when compared to the HOT condition. The %VO2PEAK utilized during the self-paced phase did not differ between HOT and PREC conditions but was lower in these situations when compared to TEMP. VO2 kinetics was enhanced during the first set in the hot environment, and precooling prevented this effect. Precooling did not affect skin temperature, thermal comfort, reported perceived exertion, water intake, or sweat rate during the exercise.
CONCLUSION:
In conclusion, precooling attenuated the distance covered reduction observed in the hot environment when compared to the exercise performed in a temperate environment. Physical performance enhancement was associated with a reduction in cardiovascular strain but not with an alteration in %VO2PEAK utilized. Precooling prevented the VO2 kinetics acceleration seen at the first set in the hot environment.