Exercise and Air Pollution: Exposure may increase risk of lung, cardiovascular damage

Posted July 9, 2007 at 02:30 PM by Bridget Sullivan

Section: Her Fitness, Her Health, Her News, Special Features

The American Council of Sports Medicine (ACSM) released the following news article on exercise and air pollution May 31, 2007.

NEW ORLEANS - An unfortunate aspect of today’s environment is the significant amount of noxious air pollutants including ozone, carbon monoxide, fine and ultrafine particulates.  This problem is especially troublesome in urban settings, near major highways, and in indoor ice arenas.  Exercising while exposed to air pollution puts people at increased risk of lung and cardiovascular damage. A featured science session at the 54th Annual Meeting of the American College of Sports Medicine (ACSM) addressed the issue of exercise and air pollution, outlining the dangers of air pollution and possible actions to help reduce risks from exposure.

Kenneth W. Rundell, Ph.D., session Chair, explained that fine and ultrafine particulates are expelled in automobile and truck exhaust, and are present in exhaust from equipment such as ice resurfacing machines. Diesel-fueled internal combustion engines produce especially high amounts of these irritants.  Fine and ultrafine particulates can be particularly harmful when people are exposed to them while exercising, since breathing hard causes an increase in deposition (the amount of particulates inhaled that remain in the lungs) and deposition fractions (percent of the amount of particulates inhaled that remain in the lungs).

“The pollutants will get deep in the airways, causing an inflammatory response in both asthmatics and non-asthmatics,” Rundell said.  “There is a resulting compromise in lung function, and a decrease in vasodilatation (the ability for arteries to expand) which results in a decrease in the amount of oxygen rich blood that reaches to the muscles.  Oxidative stress on arterial walls takes place as a result of air pollution, causing the development of arterial plaque and leading to risk for eventual arterial blockage.”

According to the American Lung Association, exercise increases air intake by as much as 10 times resting intake levels.  Endurance athletes can process as much as 20 times normal air intake.  Mouth breathing during exercise bypasses the nasal passages, the body’s natural air filters, which increases contact with pollutants and adds to vulnerability to health damage.

Exposure to fine and ultrafine particulates in the air, over as little as a three-month period, can result in decreased resting lung function at a rate that is comparable to that experienced by heavy tobacco smokers.  “The longer the exposure, the more likely the adverse effect,” Rundell said. “Unfortunately we don’t know if the damage is lasting.”

He points out that indoor ice skating arenas can be dangerous for athletes, including figure skaters, hockey players, and short-track speed skaters who already have a higher prevalence of asthma than other groups. Gasoline- or diesel-fueled ice resurfacing machines can produce excessive amounts of particulates and carbon monoxide which is expelled in exhaust.

“Rinks are typically resurfaced each hour, so there is a frequent amount of exposure from the fossil-fueled resurfacing machines,” Rundell said.  “The ventilation systems in many arenas do not adequately allow for the expulsion of these pollutants.  Athletes, as well as children who spend a lot of time in ice skating arenas, are exposed to heavy amounts of indoor air pollution while engaged in exercise.” He points out that there are several solutions to the issue.  These include transition from gasoline or propane to electric or natural gas powered equipment, use of catalytic converters in the ice resurfacing machines, keeping machines well maintained, and assuring adequate ventilation systems to allow the exhaust to escape.

Those who exercise outdoors, particularly at times when ozone and particulate levels are high, are also at risk for lung and cardiovascular damage.  These groups include children; the elderly; runners; bicyclists; and those engaged outdoor sports such as soccer, baseball and football.  “Ozone levels worsen in the later afternoon.  Fine and ultrafine particulates can be exceedingly high in locations where there is heavy automobile and truck traffic, which generally corresponds to morning and evening rush hour.  Proximity to highways and heavily traveled roads, where many schools and athletic fields are located contributes to the problem,” Rundell said.

Planning outdoor physical activity early in the morning when ozone levels tend to be lower is one way to avoid some of the risk, though this is not always practical for many youth sports teams that practice after school.  “School officials, community leaders, and parents need to be concerned and involved in addressing this issue,” Rundell said.

The American College of Sports Medicine is the largest sports medicine and exercise science organization in the world. More than 20,000 International, National and Regional members are dedicated to promoting and integrating scientific research, education and practical applications of sports medicine and exercise science to maintain and enhance physical performance, fitness, health and quality of life.

The conclusions outlined in this news release are those of the researchers only, and should not be construed as an official statement of the American College of Sports Medicine.