Effect of acclimation training on physiological changes in a randomized controlled trial in hot-humid environment

Area of Science:

• Exercise Physiology
• Environmental Adaptation
• Sports Science

Background:

• Understanding physiological responses to heat is crucial for optimizing athletic performance and safety.
• Heat acclimation training (HAT) is a potential strategy to mitigate the negative effects of heat stress on the human body.
• Limited data exists on the comprehensive physiological changes and performance enhancements following specific HAT protocols.

Purpose of the Study:

• To investigate the physiological adaptations induced by a multi-modal heat acclimation training program.
• To evaluate the impact of HAT on performance metrics, including running speed, reaction time, and perceived exertion.
• To quantify the improvement in working capacity in a hot-humid environment post-acclimation.

Main Methods:

• A randomized controlled trial involving 40 healthy males, divided into experimental (HAT) and control groups.
• The experimental group underwent HAT including meditation, running, yoga, and stepping in a hot laboratory environment.
• Physiological parameters (rectal temperature, skin temperature, sweat electrolytes) and performance tests (3000m run, reaction time, subjective perception scores) were measured before and after training.

Main Results:

• Heat acclimation training significantly shortened 3000m race times and reaction times in both room temperature and hot-humid environments compared to the control group.
• Subjective perception scores were significantly lower in the experimental group in the hot-humid environment, indicating reduced perceived exertion.
• Post-training, the experimental group maintained over 85% of their room temperature working capacity in a hot-humid environment, compared to approximately 80% in the control group.

Conclusions:

• Heat acclimation training effectively improves physiological resilience and enhances working capacity in hot-humid conditions.
• The study demonstrates that HAT leads to significant performance improvements and better subjective tolerance to heat stress.
• These findings support the implementation of HAT protocols for athletes competing in or training under hot environmental conditions.