Exercise-induced Asthma

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Exercise-Induced Asthma
Mariana Shedden, M.S. and Len Kravitz, Ph.D.

Introduction
Whether you train youth, adults, seniors, competitive athletes and/or physically challenged persons, some of your clients may have exercise-induced asthma (EIA). Individuals who suffer from chronic asthma often suffer from EIA as well, but it can also occur in individuals with no other known asthma triggers. Although the mechanisms that cause EIA are not fully understood, there are currently two main theories which attempt to explain the pathogenesis of this condition. EIA is treatable, but not always easy to diagnose. This article will relate findings from a recently published review article on EIA (Storms, 2003). It is hoped that personal trainers, fitness professionals and coaches will be able to utilize this information to help sufferers of this condition continue to perform and compete at any level, whether they be recreational or elite athletes.
What is EIA?
Asthma, which comes from the Greek language, means ‘to pant’. It is the result of an inflammation in the lung passageways, which makes breathing difficult due to airway swelling, muscular contractions and mucous production. An asthmatic’s lungs are particularly sensitive to triggers such as allergens (things that cause allergies such as dust mites), tobacco smoke, pollen, animal danders, cold air, and environmental irritants.
EIA is a condition usually distinguished by symptoms of coughing, wheezing, shortness of breath, and chest tightness during or after exercise. Some individuals may also experience stomach pain, cramps, and headaches. Many people who experience these symptoms just consider themselves out of shape, and do not seek medical advice. Thus, it is important that personal trainers and fitness professionals be aware of these symptoms and encourage those who experience them to consult a medical professional.
Sufferers from EIA can be distinguished into two categories, depending on the presence or lack of presence of chronic asthma symptoms. One group of patients only shows symptoms of asthma during or after exercise. They do not react to any of the other triggers of chronic asthma. The other group of EIA patients also has chronic asthma. Exercise is just one of the factors that trigger asthmatic symptoms in these individuals. Both groups may need to take medication before exercise to prevent EIA.
What is the mechanism of EIA?
Although the stimulants that cause EIA are not fully understood, there are two current theories that conjecture underlying mechanisms. The first theory, the hyperosmolarity theory, proposes that water loss from the airway surface liquid during exercise leads to the eventual release of pro-inflammatory mediators (intermediate substances) which cause bronchoconstriction. The second theory, the airway re-warming theory, proposes that hyperventilation that takes place during exercise cools the surface cells of the airways. This leads to a re-warming after exercise causing an eventual bronchoconstriction. Recent data has shown that inflammation is present in cold weather athletes suffering from EIA, as is discussed in the next section.
EIA in Elite Athletes
A surprising number of cold weather athletes experience post-exercise respiratory symptoms, which are compatible with EIA. Weiler and Ryan (2000) evaluated the prevalence of asthma in Olympic athletes. They reported that 22.4% use an asthma medication, have been diagnosed with asthma or both. They concluded that athletes who performed Nordic sports, cross-country, and short track events had a higher likelihood to have been diagnosed with asthma. Similarly, Leuppi et al. (1998) found that 19% of ice hockey players were diagnosed with asthma and 11.5% with EIA. Asthma and bronchiohyperreactivity described as the hyperresponsiveness to stimuli such as allergens and irritants, seems to be more frequent in athletes who train strenuously at lower temperatures. Also, Mannix at al. (1996) demonstrated a 35% incidence of EIA in figure skaters. They suggested that these athletes are at higher risk of EIA due to their continued exposure to cold temperatures. Many of the athletes have no prior history of asthma and no family history of asthma. Storms (2003) concluded, “In cold-weather athletes, there may be some chronic airway injury due to their continued inhalation of large volumes of cold air during training. The injury caused leads to symptoms which mimic true asthma”. Although the symptoms in these cold-weather athletes often mimic true asthma, some studies have shown that the same treatment may not be indicated. Sue-Chu et al. (2000) studied cross-country skiers with symptoms of EIA. Airway inflammation was detected in these skiers, but when treatment with inhaled steroids was prescribed, no beneficial effect was seen. Due to the lack of response to the usual asthma therapy in these skiers, this study suggested that the commonly reported symptoms of EIA in cold-weather athletes might in fact represent a separate condition from EIA, which may require a different treatment.
Treatment of EIA
For the recreational athlete, the best treatment may simply be to avoid activities that are most likely to cause asthma attacks, such as cold-weather sports. Some of the activities that are least likely to cause asthma symptoms are swimming (due to the humidity in the inhaled air) and intermittent exercise or team games. Another recommended strategy is to warm-up at approximately 60% of VO2 max for 15 minutes before beginning formal exercise (McKenzie, McLuckie & Stirling, 1994). Subjectively, this is a moderate intensity, which would be a 12 to 14 RPE on the Borg ratings of perceived exertion scale (6-20 range). This has been shown to decrease post-exercise bronchoconstrictions. In addition to the measures described above, medication may also be prescribed. Some individuals will be medically prescribed to take a pre-exercise medication, while others will also take a medication that combats the symptoms of chronic asthma as well. Elite athletes will find it more difficult to avoid activities that commonly cause asthma attacks, since they are competing in a specific sport. However the number of Olympic athletes who suffer from EIA and overcome it demonstrates that EIA does not prevent high levels of athletic achievement. The following table highlights exercise recommendations from Nieman (1998) and others.

Table I. Exercise Recommendations for Clients with Asthma or EIA

As a precaution, seek prior physician’s clearance for your client.
Determine the medications being taken by your client and learn the possible side effects.
Plan a dynamic warm-up of approximately 15 min. at 60% VO2 max (McKenzie, McLuckie & Stirling, 1994), which is similar to a 12 to 14 RPE. The warm-up is important in reducing the occurrence of EIA episodes.
Outdoor running is regarded as the most conducive to EIA. This is followed by treadmill running, cycling, and walking. Aquatic exercise (e.g. swimming and aqua exercise) seldom leads to EIA because warm and humid air near the water surface helps to prevent cooling and drying of lung airways.
Indoor water or land exercises are recommended.
Interval training is fine to incorporate in an exercise program, but show prudence with the higher exercise intensities.
Stop-and-go sports like tennis and volleyball lead to less EIA for some people.
Yoga practice may enhance relaxation and exercise tolerance (Vedanthan et al, 1998). This is also why a prolonged cool-down is recommended.
Teach clients slow nasal breathing. Breathing through the nose warms and humidifies the air better and can be done with some low-to-moderate exercise intensities.
Wearing a mask or scarf in cold weather can increase the temperature and humidity of the inhaled air, reducing irritation to the air passageways.
Always closely monitor the client for any signs or symptoms of an asthma attack.
Avoid the exercise environments that have pollutants, high pollen, and other triggers (e.g. a recently mowed grass field, an area with many flowers, and high traffic roadways).
In the case of an asthma attack, immediately decrease exercise intensity.
If symptoms do not subside, seek medical attention.
Advise proper hydration before, during, and after exercise (which of course is a recommendation for all exercise enthusiasts).

Summary
All asthmatic and EIA person should be made aware of the benefits of physical activity and exercise as described in Table 2. Personal trainers, fitness professionals and coaches are encouraged to learn and be aware of EIA symptoms so they can successfully design exercise programs for both recreational and elite athletes who suffer the effects of these conditions, but can overcome them!

Table 2. Benefits of Exercise Training in Clients with Asthma or EIA

Increased cardiorespiratory fitness
Increased work capacity
Improved exercise endurance
Reduced perception of breathlessness
Reduced anxiety about physical activity
May alleviate asthma symptoms
May decrease the use of inhaled and oral steroids

References
Karjalainen, E.M. et al. Evidence of airway inflammation and remodeling in ski athletes with and without bronchial hyperresponsiveness to methacholine. Am. J. Respir. Crit. Care Med. 161(6):2086-2091, 2000.

Leuppi, J.D., Kuhn, M., Comminot, C., and Reinhart, W.H. High prevalence of bronchial hyperresponsiveness and asthma in ice hockey players. Eur. Respir. J. 12(1):13-16, 1998.

Mannix, E.T., Farber, M.O., Palange, P., Galassetti, P., and Manfredi, F. Exercise-induced asthma and figure skaters. Chest 109(2):312-315, 1996.

McKenzie, D.C., McLuckie, S.L. Stirling, D.R. The protective effects of continuous and interval exercise in athletes with exercise-induced asthma. Med. Sci. Sports Exerc. 26(9):951-956, 1994.

Nieman, D.C. The Exercise-Health Connection. Human Kinetics, 1998.

Storms, W.W. Review of exercise-induced asthma. Med. Sci. Sports Exerc. 35(9):1464-1470, 2003.

Sue-Chu, M. et al. Placebo-controlled study of inhaled budesonide on indices of airway inflammation in bronchoalveolar lavage fluid and bronchial biopsies in cross-country skiers. Respiration 67(4):417-425, 2000.

Vedanthan, P.K., et al. Clinical study of yoga techniques in university students with asthma: a controlled study. Allergy Asthma Proc. 19(1):3-9, 1998.

Weiler, J.M. and Ryan, E.J. 3rd Asthma in United States Olympic athletes who participated in the 1998 olympic winter games. J. Allergy Clin. Immunol.
106(2):267:271, 2000.

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