Asthma (Greek, "to pant") is an inflammation of the lungs, which causes airways to narrow, making it difficult to breathe. Inflammation makes the airways sensitive to allergens, chemical irritants, tobacco smoke, cold air, or exercise (3, 5). When exposed to these stimuli, an asthma attack can occur, causing the muscles around the windpipes to tighten, making the opening smaller. The lining of the windpipe swells (becomes inflamed) and produces mucus. This leads to coughing, wheezing, chest tightness, and difficulty in breathing, particularly at night or in the early morning. Asthma symptoms come and go; they can last for a few moments or for days. Asthma attacks can be mild or severe and sometimes fatal.
Of the various triggers for asthma, physical activity is one of the most common (2, 4). More than 80% of children and 60% of adult asthmatics get exercise-induced asthma (EIA) during or after exercise. In the 1972 Olympic Games, EIA gained considerable attention when an American swimmer lost a gold medal due to the use of a banned drug to treat asthma (2). Recognition that EIA could be controlled with proper medication and education grew, following reports of the success of U.S. Olympians. Of 597 U.S. athletes in the 1984 Olympic summer games in Los Angeles, 11% reported a history of EIA. These athletes still won 41 medals. In the 1988 Olympic Games in Seoul, about 8% of U.S. athletes were confirmed asthmatics and won, proportionately, as many medals as did athletes without asthma. At the 1998 Olympic Winter Games in Nagano, Japan, 22% of U.S. athletes had asthma, but rates varied widely among the sports (4).
Although not entirely understood, most clinicians feel that EIA is triggered as the lining cells of the airway are cooled and dried during exercise (3). As air is taken into the lungs, it is warmed and humidified, resulting in a cooling and drying of the airway lining. Certain chemicals are then released by the lining cells, causing the airways to tighten. This cooling and drying are worsened by several factors, including exercising in cool and dry air, a switch from nasal to mouth breathing, and fast and deep breathing from intense exercise. If pollutants and pollen are in the air, the risk of EIA is increased (2, 4).
Asthma and Exercise
Individuals with well-controlled asthma can exercise. However, patients with asthma, particularly those with exercise-induced asthma (EIA), should pay special attention to avoiding environmental “triggers” such as cold, dry, dusty air and/or inhaled pollutants, chemicals. Individuals suffering from acute asthma should not exercise until symptoms have subsided.
Asthma typically results in dyspnea or shortness of breath with exertion. As a result of this dyspnea, asthma patients limit their physical activity, and deconditioning results. Consequentially, asthmatics experience even greater dyspnea with even lower levels of physical exertion. Unless this vicious cycle can be broken, the asthma patient eventually becomes disabled and functionally impaired. Exercise has been shown to be an effective intervention that can break this cycle and prevent disability and functional impairment (1).
The use of exercise training in children with asthma is controversial because there appear to be few effects on its defining feature, that is, bronchoconstriction. Training does, however, lead to improved cardiorespiratory fitness and reduced breathlessness at a given exercise intensity in asthmatic children. There may also be psychosocial benefits. The need for medication may be reduced but this is a complex issue, because exercise is a potent stimulus to bronchoconstriction and children need prophylactic medication before each session. A session of exercise may bring on asthma symptoms in about 80% of people with the disease. However, in both adults and children with asthma there is evidence to suggest that in many cases exercise performance is more limited by lack of fitness than by underlying asthma. Therefore it is legitimate to encourage physical activity, assuming that underlying medication is adequate.
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Learn how an Accredited Exercise Physiologist can help you to begin and maintain exercise in your life, so you can enjoy the health benefits of Exercise for Diabetes:
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