Impact of Pollution, Heat and Humidity on Athletic Performance

Abstract

The 2008 Olympic Games will take place in Beijing, a city that presents high concentration of different pollutants. One of the primary pollutants that is of concern to athletes competing in Beijing is the oxidant gas ozone, especially when combined with the heat and humidity (H) of the summer months. PURPOSE: To investigate the impact of a hot, humid and ozone polluted environment during an 8 km time trial run on (a) inflammatory response in the lungs, (b) changes in lung function and (c) performance. METHODS: Using a single blinded randomized design, 8 male endurance athletes (mean ± SD, 25 ± 5 years; 73 ± 8 kg; 182 ± 9 cm; 64 ± 3 ml.kg-1.min-1) took part in a time trial run in four different environmental conditions: 20°C + 50% H (Control); 20°C + 50% H + 0.10 ppm O3 (Control + O3); 31°C + 70% H (Heat); 31°C + 70% H + 0.10 ppm O3 (Heat + O3). Heart rate (HR), RPE and expired air were collected during the exercise. Nasal lavage samples were collected post-exercise to analyse the neutrophil count in the upper respiratory airways. Lung function was measured pre and post-exercise. Respiratory symptoms were also recorded. Data was analysed using Repeated Measures ANOVA with Tukey's post-hoc test. RESULTS: The mean speed attained on the Heat + O3 trial (14.8 km·h-1) was significantly lower when compared with the Control (16.1 km·h-1). The completion time of both Heat (32m03s) and Heat + O3 (32m26s) was significantly higher when compared with the Control (29m53s). Even though there is no statistical difference between the Heat and the Heat + O3 trials, the time to complete the latter was, on average, 23 sec longer when compared to the former. In a competitive 8 km race environment, this time difference could be ecologically very significant. Mean and peak HR did not differ between trials, whereas mean and peak RPE (16; 18) was significantly higher in the Heat + O3 when compared with the Control (15; 17). Respiratory symptoms reported by the athletes increased following Heat + O3 and all of them reported not being able to perform maximally if it were a competition. No significant differences in the mean lung function or neutrophil counts were found. CONCLUSION: Ozone alone does not impair performance. However, combined with heat and humidity then significant performance decrements may be seen. Supported by Napier University and UK Sport.