Exercising in Extreme Heat: How Can Performance Be Preserved While Reducing Health Risks?

By Ana Espino | Published on June 29, 2026 | 4 min read


With climate change and the increasing frequency of heatwaves, engaging in physical activity in hot environments has become a growing concern for both athletes and professionals exposed to strenuous physical work. Although the decline in performance during exercise in the heat is well recognized, the physiological mechanisms involved and the most effective strategies for minimizing their impact continue to be the focus of extensive research.

In a landmark review published in Physiological Reviews, Periard and colleagues provide a comprehensive overview of current knowledge on the effects of heat stress during exercise. The authors examine the mechanisms of thermoregulation, the impact of dehydration on physical performance, and the main strategies for reducing heat-related health risks.



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Rising Body Temperature Progressively Limits Physical Performance

During prolonged exercise, the body generates a substantial amount of heat. To maintain an internal temperature compatible with normal organ function, it activates several defense mechanisms, particularly sweating and cutaneous vasodilation, which promote heat dissipation. However, when environmental conditions become excessively hot or humid, these mechanisms become less effective, leading to a progressive increase in core body temperature.

This hyperthermia affects multiple physiological systems. The cardiovascular system is placed under considerable strain as it attempts to supply blood simultaneously to the working muscles and the skin, while both the central nervous system and skeletal muscles experience reduced functional capacity. The result is earlier fatigue, diminished endurance, and impaired athletic performance, effects that become even more pronounced as dehydration develops. Fluid losses through sweating reduce blood volume, impair the body's cooling capacity, and further increase thermal stress.

Beyond performance impairment, prolonged exposure to heat can lead to potentially serious heat-related illnesses, ranging from muscle cramps and heat exhaustion to exertional heat stroke, a true medical emergency requiring rapid cooling to minimize neurological damage and multiple organ complications.



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Heat Acclimatization and Cooling Strategies: The Cornerstones of Prevention

The authors emphasize that several measures can effectively reduce the harmful effects of heat exposure. Progressive heat acclimatization is one of the most effective interventions. After several days of repeated exposure, the body improves its sweating capacity, expands plasma volume, and becomes more efficient at dissipating heat.

Appropriate hydration also helps preserve thermoregulatory function, although the optimal strategy for replacing fluid losses remains the subject of ongoing debate. Various cooling techniques, applied before or during exercise, can also improve heat tolerance, particularly during competitions held in challenging environmental conditions. However, the authors point out that the effectiveness of these interventions depends on the type of activity, the prevailing climate, and the individual characteristics of each athlete.

This review confirms that exercising in extreme heat is not merely a challenge to athletic performance but also a significant public health concern. In the context of global warming, a better understanding of thermoregulatory mechanisms and the appropriate implementation of preventive strategies will be essential to reduce health risks among both athletes and workers exposed to high temperatures.  





About the author – Ana Espino
PhD in Immunology, specialized in Virology  
As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions.