By Helen Owton

At the recent Athletic World Championships in Beijing, not only did the athletes have to train for heat and humidity, they were also faced with competing in one of the world’s most polluted cities. Unfortunately, coping with poor air quality is nothing new for the world’s top athletes.

As the world looks forward to next year’s Olympic Games in Rio de Janeiro, concerns have been raised about the city’s water pollution. But the Brazilian metropolis also suffers from similar air quality problems to those of most major developing world settlements, which can cause [significant short and long-term health issues. Even major developed cities such as 2012 Olympic host London, which have relatively clean air compared to the worst offenders, regularly breach international guidelines on “safe” levels of air pollution.

Air pollutants involve a complex mixture of small and large particles of varying origin and chemical composition. This includes fossil fuel emissions, industrial dust, windblown soil and secondary pollutants formed from reactions in the atmosphere. The particulate matter, ozone, nitrogen dioxide and sulphur dioxide that this is made up from have all been shown to have a profound effect on physical performance but also lung function and health more generally.

Two of the main causes of air pollution in many cities are the presence of polluting industries and the large daily number of vehicles. Car emissions are estimated to be the greatest single contributor to urban air pollution. Their toxic constituents contribute to respiratory disease, cardiovascular disease and cancer.

In London, for example, the poor air quality has been responsible for a total of 9,416 premature deaths. Estimated figures for the future suggest that air pollution in Britain may be responsible for 60,000 early deaths a year. In Beijing, figures suggest that air pollution is responsible for 1.2m deaths a year (40% of the global total). These premature deaths could be prevented if air quality was improved.

Health impacts

Athletes visiting a polluted city for a competition don’t seem likely to suffer the same long-term health effects as its inhabitants (although recent research challenges this idea), but pollution can limit their performance. Those who compete in endurance competitive races such as the marathon are most at risk because the marked increase in their breathing rate and amplified nasal and oral functions mean they breathe in more pollutants.

At the recent Beijing event, for example, athletes may have inhaled increasingly large doses of ozone and fine particles. This could have made respiration more difficult and reduced the amount of oxygen getting to the muscles, significantly impairing performances in endurance events.

Fine particles are more dangerous because they can be inhaled deeper into the lungs and so take longer for the body to remove, increasing the potential for adverse effects. Higher quantities of ozone primarily influence on the lungs and respiratory tract, causing the smooth muscles surrounding the airways to constrict.

Some athletes are more sensitive to air quality than others. For example, those with chronic respiratory diseases such as asthma react more to ozone than the general population. Some research also suggests there may be genetic differences in how susceptible individuals are to pollutants. And while it is possible to develop a tolerance to pollutants such as ozone, this sort of exposure may be potentially harmful because of the damage to or loss of the body’s normal defence mechanism.

Taking action

British athletes have recently been given pollution masks, which might protect the respiratory system from the effects of toxic gases and pollutants, but research is limited and inconclusive. There isn’t much evidence to suggest that it even works. Additionally, some argue that wearing the masks may limit performance because athletes are not accustomed to wearing them.

Athletes can also take antioxidant supplements, which have been shown to slightly improve the adverse effects of pollutants. They work by countering the oxidative stress mechanism, the breakdown of the body’s ability to detoxify or repair the damage caused, associated with such pollutants.

In the long-term, however, athletes will continue to risk competing in polluted environments unless sports authorities take more of a stand against holding events in highly polluted cities. Tokyo is hosting Olympic 2020, where they are struggling to maintain safe pollution levels, and Beijing has again been named as the next host city for the Olympic Winter Games 2022.

The Olympic Games may act as a vehicle for change in some cities, but how many times must athletes put their bodies on the line before this change includes pollution? Perhaps it’s time sports bodies prioritised their athletes and included stricter environmental regulations, such as endorsing testing for viruses from water pollution, when awarding competitions.

Helen Owton, Lecturer in Sport & Fitness, The Open University

This article was originally published on The Conversation. Read the original article.