ELITE SPORTS MEDICINE

POLLUTION AND PERFORMANCE

By Dr Greg Whyte PhD

INTRODUCTION The summer months mark the start of the competitive season for a number of outdoor sports, and the warm weather and increase in daylight hours also contributes to a boost in outdoor activity. The occasion of the 2004 Olympics in Athens, a city renowned for its high temperatures and high pollution levels, means the impact of these factors on our Olympic athletes will be a major issue for sports medicine professionals not only in the UK but all over the world.

The increase in hours of sunlight gives rise to an increase in air pollution, the highest of which are experienced during the peak summer months. Air pollution is primarily comprised of compounds derived from the combustion of fossil fuels and automobile emissions including: ■ oxides of sulphur ■ oxides of nitrogen ■ carbon monoxide ■ particulates ■ lead ■ ozone.

These pollutants are intensified by sunlight and may have a variety of negative effects including: ■ impaired pulmonary function ■ chest pain ■ coughing ■ wheezing ■ eye and skin irritation.

The impact of pollution will be exacerbated in individuals with underlying disease, in particular asthma and chronic lung and heart disease. The magnitude of decrement in lung function is known to be a function of the ‘effective dose’.

The ‘effective dose’ is a product of pollution concentration, minute ventilation during exposure and duration of exposure (1). In the case of the exercising individuals an increased ventilation for pro- longed periods of time leads to a higher exposure to pollution. Furthermore, the increased velocity of air entering the lungs and the reliance on mouth breathing, results in an increased exposure of the lower airway branches leading to further decrements in lung function (1).

The following article will examine the effect of three key pollutants (ozone, NOx, and particulate matter) on exercise performance, and will go on to explore ways in which we can limit their effects.

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