Medical experts warn that even if one's intentions to exercise and keep in shape are good, urban environment may not be as favorable and propitious for our health. Therefore, exercising outdoors may be harmful for our health due to all the air pollutants widely spread in big industrial centers.

At highest risks from air pollution were found to be individuals who exercise by skating, bicycling or running, as they mostly develop their activities outside. Airborne pollutants met outdoors affect and irritate the lungs, causing diseases in people who prefer to exercise outside or worsening their health disorders. Outdoor pollutants affecting the lungs are mostly connected to pulmonary and respiratory health conditions, such as emphysema, asthma, bronchitis, cardiopulmonary diseases etc.

People who exercise outdoors are mostly exposed to three very harmful components of air pollution: fine particulates, ozone and carbon monoxide. The first type of airborne pollutants - fine particulates - relate to a combination of solid particles and liquid droplets and are mainly emitted by diesel engines of trucks and buses. Ozone, a gas composed of three atoms of oxygen, is the main component of smog in big cities. Carbon monoxide is produced by cigarette smoke and automobile exhaust and can even lead to death in an individual by removing the oxygen out of one's circulatory system.

In his article about exercising outdoors and air pollutants appearing on the web page of the New York-Presbyterian Hospital/Weill Cornell Medical Center, Dr. Joseph T. Cooke pointed out: "The pollutants affect the lungs by causing inflammation or irritation of the airway lining. More mucus and phlegm is produced, and small muscles surrounding the airway respond by squeezing down. The work of breathing increases and it becomes more difficult to get oxygen into the body."

Dr. Joseph T. Cooke is an Associate Professor of Clinical Medicine and Patient Safety Officer at New York-Presbyterian Hospital/Weill Cornell Medical Center. For those who exercise in big, polluted cities, Dr. Cooke mentioned several very useful advices to be considered by the physical exercise adepts. They should avoid roads with heavy bus or truck traffic; try working out outside only during early mornings and late evenings, not at noon when the traffic is at its highest; if possible, exercise indoors for a change; if they notice any difficulty in breathing or other irritating symptoms, individuals who exercise outside should immediately see their doctor.