Clinicians prescribing exercise: is air pollution a hazard?

In summary, there is sound evidence for an exposure-dependent relationship between air pollution, morbidity and mortality, particularly in relation to cardiovascular and respiratory illnesses. Although regular aerobic exercise is recommended for good health, there may be adverse health consequences for people who habitually exercise in areas of high ambient pollution. Despite this, it is not uncommon to see people running or cycling alongside congested roadways, and clinicians should advise patients to exercise on quiet roads or in parks and recreation areas. The best time of day to exercise is early in the morning, before the build-up of traffic and when it is cooler. This is relevant because the combination of sunlight and heat with certain compounds increases zone production. Importantly, certain groups may be acutely susceptible to the effects of air pollution, and clinicians should advise them accordingly.