Investigating performance and lung function in a hot, humid and ozone-polluted environment

Area of Science:

• Environmental Exercise Physiology
• Sports Science
• Air Quality and Health

Background:

• Urban sports events often occur in hot, humid, and polluted environments.
• High temperatures, humidity, and ozone (O3) can negatively impact athletic performance and physiological responses.
• Understanding these environmental factors is crucial for athlete safety and optimal performance during competitions.

Purpose of the Study:

• To investigate the impact of hot, humid, and ozone-polluted environments on 8 km time trial run performance in endurance-trained runners.
• To assess the effects on pulmonary function and subjective respiratory symptoms.
• To determine if ozone pollution exacerbates the negative effects of heat and humidity on performance.

Main Methods:

• A crossover randomized design involving 10 male endurance-trained runners.
• Four environmental conditions were tested: Control (20°C, 50% RH), Control + O3 (20°C, 50% RH, 0.10 ppm O3), Heat (31°C, 70% RH), and Heat + O3 (31°C, 70% RH, 0.10 ppm O3).
• Performance (8 km time trial), pulmonary function (pre/post-exercise), and respiratory symptoms were measured.

Main Results:

• Run completion times were significantly slower in both the Heat and Heat + O3 conditions compared to the Control and Control + O3 conditions (P < 0.0001).
• No significant changes in pulmonary function were observed between pre/post-exercise measurements or across different trials.
• Ozone pollution at the tested concentration did not significantly worsen performance beyond the impairment caused by heat and humidity.

Conclusions:

• Hot and humid environments significantly impair endurance running performance.
• Environmentally relevant concentrations of ozone do not appear to compound the performance decrements caused by heat and humidity in runners.
• Heat and humidity are the dominant environmental factors affecting performance in this context, with minimal additional impact from ozone pollution.