The number of top athletes using anti-asthma drugs is high, according to various surveys. This may indicate a particular relationship between physical activity and respiratory disease. Is exercise healthy for the respiratory system or not? And how can you stay physically active even as an asthmatic?
If one takes the trouble to read through the latest statistics of WADA, the World Anti-Doping Organization, one is not badly surprised to find that beta-2 agonists, specific anti-asthma drugs, are very frequently found in urine analyses, accounting for 5% of all nearly 300,000 tests. Apparently, elite athletes often use such agents, which may inevitably raise the (not definitively resolved) question of the relationship between these drugs and performance-enhancing activity. It must be emphasized, however, that these 122 “positive” cases only very rarely have to be punished, since the athletes concerned usually have a permit (exceptional therapeutic use permit, ATZ) that allows them to use the product that is actually banned to a certain extent.
If the frequency of ATZ entries, independent of the more infrequent controls, had been taken as a study parameter, the requests for beta-2 agonists would have ranked first among all requests. It is astonishing to learn that at the 1994 Winter Olympics in Lillehammer 70% of all athletes presented such a certificate, at the 1998 World Swimming Championships in Perth even 80%, and that at the 2000 Summer Olympics in Sidney every fifth participant was an asthma drug user. Such figures suggest that there is something “interesting” in these drugs, even if the available scientific papers on the subject cannot prove anything similar. But whether that itself is already the proof?
Whatever the final interpretation, the high number of athletes using anti-asthma drugs suggests a strong link between physical activity and respiratory disease.
How does breathing work during sports?
A brief reminder of respiratory physiology may be useful at this point. A healthy adult breathes in and out about 20,000 times during 24 hours. This allows approximately 10,000 liters of air to pass through the lungs daily. In general, people breathe more often during exercise than at rest – more air is ventilated with each breath. At rest, six to eight liters are moved per minute; under stress, about 20 times more. Highly endurance-trained athletes can inhale and exhale up to 250 liters of air per minute during the most intense exercise! In this case, normal nasal breathing is no longer sufficient; mouth breathing is called upon to help, without the filtration and warming processes of nasal breathing, which are so important. Thus, cold “dirty” air flows down the bronchial tree at the greatest speed, with the risks of unhealthy irritation.
Asthma – a common problem
It is therefore not incomprehensible that more and more amateur and professional athletes have asthma – and at the same time it is not surprising that more and more asthmatics, including many children, are taking part in sports. This statement is logical in itself, if we take note that 5% of the population suffers from asthma, with a tendency to increase. This common disease has manifold effects on the health of the affected person, and one of them is the so-called deconditioning. Physical activity, often reduced (to nonexistent) due to fear, leads to a reduction in conditioning factors such as aerobic capacity, strength, and agility (to name only the main factors affected). This results in decreased self-esteem, anxiety, and discontinued social contacts. And this is still happening today, even though pulmonologists never tire of emphasizing that asthmatics should live as normally as possible and be allowed, even required, to exercise.
Thus, sports therapy is part of the selection of treatment measures, even though it seems clear, based on current knowledge, that such measures do not treat asthma per se. However, it is undisputed that normal exercise capacity can be achieved with targeted adapted physical training without negative effects on asthma. A consistent therapy that keeps the underlying disease well under control is the basic prerequisite for regular sports activities. Peak flow measurements for self-assessment and regular medical follow-up are important for asthmatics who exercise. Warming up carefully, moving indoors when pollen or air pollutant concentrations are high, and adapting training to avoid intense endurance and strength training while favoring flexibility and coordination training are other measures and attitudes that make exercise safe and effective for asthmatics.
It is especially important to guide children suffering from asthma according to these proven principles. Far too often these young people are overprotected by concerned parents, which on the one hand is unnecessary and on the other hand is fraught with negative consequences – namely the same consequences as with adults: Deconditioning and social isolation. These develop in even worse ways at a young age, and sports therapy is even more important in adolescents. Targeted care is a team effort, where parents, teachers, and physicians all have to pull together.
Bronchial asthma vs. AIA
From a sports medicine perspective, it is very important to distinguish asthma (bronchial) from exercise-induced asthma (“exercise induced asthma” [AIA]). Many athletes suffer from AIA rather than asthma, which has different therapeutic consequences.
Exercise-induced asthma is common and found in nearly 10% of the population. This disorder mainly affects people with known “classical” asthma (70-90%) and those with allergic diathesis (35-40%). Exercise-induced asthma is temporary bronchoconstriction during or after intense physical exertion that resolves after a relatively short period of time (15-20 minutes) after the performance is discontinued. Clinically, symptoms appear six to eight minutes after the onset of exercise. There is no whistling breathing (as characteristic of asthma), but a so-called expiratory “wheezing”, accompanied by dry cough and thoracic pressure sensation. Shortness of breath, which is also usually complained of, is not a good indication of AIA, as dyspnea is usually a normal symptom of physical exertion.
Athletes of endurance disciplines (cross-country skiing, cycling, track and field, swimming) are preferentially affected by performance asthma, but figure skaters and ice hockey players (nitrogen oxides) can also be affected. AIA can be triggered by various stimuli such as cold or very dry air, as well as gaseous substances such as chlorine gas (swimming pools) or chemicals used in rink preparation. It is interesting to note that in certain swimming pools, the layer of air immediately above the water, and thus inhaled by the swimmer, contains concentrations that are not tolerated in working environments.
The pathogenesis of AIA is now considered multifactorial. The hyperosmolar environment in the bronchial tubes, generated by water evaporation and favored by the strong ventilation, the dry and often cold inhaled air and the irritants mentioned, among which ozone is included, seems to play a central role. This causes the secretion of mediators such as histamine, a potent bronchoconstrictor. But climatic conditions also make themselves felt. In one study, it was shown that 43% of competitive cross-country runners from Sweden suffered from AIA compared to only 14% of Norwegians. The latter country generally experiences wetter milder weather due to the Gulf Stream.
Remember in practice
As soon as complaints such as a frequently stuffy nose, cough, pressure or tightness in the chest, restricted breathing or performance limits due to shortness of breath after exercise are noticed, one should think of an AIA and seek medical clarification. The general practitioner can usually already suspect the disease on the basis of this anamnestic information. However, a pulmonary functional examination is always needed to confirm a performance asthma. In addition to determining respiratory function at rest, a bronchoprovocation test (e.g., methacholine test or others) is usually performed today. In this case, the airways are provoked by an inhalant. In performance asthma, the bronchial tubes constrict and the discomfort experienced during exercise occurs during the test. A medication inhaled afterwards makes the discomfort subside again. Other examination methods such as standardized tests on a bicycle or treadmill can also be used.
How to treat?
Therapeutically, in reliably diagnosed sporadic exercise-induced asthma, a beta-2 agonist should be used 15 minutes before physical activity; in regular attacks or if the physical activity is performed regularly, rather a combination preparation (beta-2 agonist + inhaled steroid).
Very important as a supplement to these pharmacological means are sport-technical measures such as a sophisticated warm-up program, which approaches up to 80% of the performance maximum. This means that a seizure-free interval can often be achieved for up to three hours for the actual training. After that, training should not be abruptly stopped and sudden temperature changes should be avoided. After exercises in the cold, do not immediately move to the warm cabin, but cool down slowly from the workout outside and go inside later. Occasionally, a low-salt diet results in an attenuation of asthma attacks.
Sport is healthy. This statement is also true for asthma patients. It only takes some knowledge to reduce the risks to a minimum.
HAUSARZT PRAXIS 2015; 10(11): 3-4
