The effect of cold water immersion on exhaustion time, serum levels of lactate and electrolyte indices of untrained men following an exhaustive exercise in the heat conditions

Warm and humid conditions are the main limiting factor in long-term activities. Thus, the purpose of this study was to determine the effect of pre-cooling (PC) on exhaustion time, plasma levels of lactate and, electrolytes status of untrained men following an exhaustive exercise in the heat conditions. The participants were 20 untrained male students aged 19 to 21, which were randomly assigned to control and experimental groups (n=10). Core body temperature, skin temperature, heart rate, blood pressure, plasma lactate, and electrolytes were measured in three stages: at baseline, after warm-up and PC, and following the exhaustive test. The PC method consisted of immersion in the cold water (26 °C) for 10 minutes (ambient temperature 32-34 °C). The exhaustive exercise protocol included treadmill running (at 33 °C, 50% humidity) at the speed of 7 km/h, which gradually increased to 10 km/h up to exhaustion. The SPANOVA was used for data analysis; and the criterion of significance was set as p< 0.05. Exercise time to exhaustion was longer (p<0.0001) in the PC than in the control conditions. PC decreased oral (p=0.05) and skin (p<0.0001) temperatures and lactate level (p=0.0001). However, there were no significant differences in plasma K and Na concentration. In conclusion, the PC increases endurance performance in a hot environment through enhances heat storage, decreases lactate level and cardiovascular strain.