Fact sheet: Exercise-induced asthma

It can be frightening to suddenly have problems breathing or to hardly get any air when doing sports. These breathing problems can be caused by exercise-induced asthma – although difficulties breathing after physical exertion can also occur if people are not physically fit. For some people with asthma this can become a vicious circle: Too much physical exertion can trigger asthma attacks – but too little physical activity can also lead to reduced lung performance.

Having had the unpleasant experience of problems breathing some children, teenagers and adults may no longer dare to do exercise. But even though there is a small risk of triggering asthma symptoms, you can still do sports safely despite having asthma if you know how to deal with the symptoms and how to ease asthma attacks. In this fact sheet you can find out why there is no need to stop doing sports despite having asthma and what medication can help lower your risk of asthma attacks. Asthma need not hinder an active life of stamina, fun and confidence.

What is exercise-induced asthma?

Many people with chronic (long-term) asthma have already experienced severe breathing problems after they do sports. When physical strain leads to symptoms typical of asthma like breathlessness, this is called exercise-induced asthma. Sometimes people who do not have asthma have this kind of symptoms after doing physical exercise.

Asthma – called bronchial asthma or asthma bronchiale in medicine – is a chronic disease of the airways that is often closely associated with an allergy. To read more about asthma and the airways click here. The airways of people with asthma are overly sensitive. They are often inflamed, resulting in swollen membranes, the build-up of thick mucus and the tightening of the muscles around the airways. This makes the airways narrower, which can cause wheezing, shortness of breath, difficulties breathing, coughing or the urge to cough, and chest tightness. These symptoms can come on suddenly and very strongly, making it very difficult to breathe. These asthma attacks can be very frightening and people may even panic.

Asthma attacks can be triggered by various things, including allergic reactions and physical exertion, especially sports. About 70 to 90% of all people who have asthma are affected by exercise-induced asthma.

When we breathe in, our nose cleans, warms up and moistens the air. During exercise we breathe in through our mouth more, so our nose can no longer “prepare” the air in this way before it reaches our lungs. We also breathe faster and deeper during exercise, so the air in our lungs is not as warm and moist as usual, which makes the membranes lining the bronchi swell. Together with the lungs’ constant readiness to start an inflammatory response, this causes the airways to become narrow. Cold and dry air can increase this effect. That is why people are more likely to have exercise-induced asthma when doing winter sports.

The following factors influence how severe exercise-induced asthma attacks are:

• how hypersensitive your bronchi are
• what medication you are taking
• how intense the physical exercise is
• how long ago you last did physical exercise
• the environmental conditions (including air temperature and humidity or pollen levels)

Exercise-induced asthma attacks normally start about 5 to 10 minutes after you have stopped the physical activity, and only rarely during the activity itself. The symptoms usually go away after about 30 to 45 minutes.

How is exercise-induced asthma diagnosed?

Exercise-induced asthma often first arises in childhood and the teenage years. Because they are generally very active, children and teenagers are quite likely to become short of breath if they are prone to this kind of asthma. It is a good idea to have things checked out by a doctor if this happens, to find out whether it is asthma.

To see whether physical activity triggers asthma attacks, an exercise test is typically carried out. This may involve, for example, getting on a treadmill or exercise bike for several minutes. Tests are done before and after the person exercises to see how much the physical activity affects their breathing.

One commonly used way to test lung function is an approach called spirometry. Spirometers are electrical or mechanical devices that measure your breathing and your lungs. In this test you breathe into and out of the spirometer through a tube. Another test method involves a device called a peak flow meter. Here you quickly breathe out into the device as hard as you can. The peak flow meter measures the speed at which the air leaves your airways, which indicates how constricted your airways are.

Is doing sports helpful or harmful?

Overall, there are more benefits than harms in being physically fit and active when having asthma. Once you have learned how to deal with asthma attacks and how to use medication in order to prevent the disease from getting worse, you can still do sports if you have asthma. The disease would not even stop you from doing competitive sports. Many people who participate in the Olympic games and other top athletes have asthma too.

Exercise and sports can have important positive effects: they can strengthen your heart and lungs, improve your uptake of oxygen and increase the amount of air you breathe in and out. This makes people – including those who have asthma – more resilient. But it is important to choose activities that suit your level of fitness. If you notice signs that you are getting short of breath, you should take a break or do something less strenuous. For some people warming up might be helpful before doing sports. There is not enough research on the advantages and disadvantages of warming-up exercises, however.

It is also important to have your reliever medication with you so that you are able to react quickly if you ever do have an asthma attack after all. Sometimes it may help to use reliever medication before physical exertion. It is best to talk to your doctor about whether this is the case with you and when you should do it.

Are some types of sport more suitable than others?

It is difficult to say whether some types of sport are more “asthma-friendly” than others: So far, there is not enough scientific research in this area. But swimming is probably less likely to cause exercise-induced asthma than running or cycling. You can read more about this here. If you do outdoor sports it is important to know that cold and dry air is more likely to trigger exercise-induced asthma.

No matter what type of sport you choose to do, it is a good idea to gradually increase the level of exercise. In other words, if you are not very fit and have asthma it might not be advisable to suddenly start off sprinting or lifting heavy weights. It is better to begin slowly, for example with brisk walking, jogging, swimming, hiking or another endurance sport you enjoy and feel comfortable doing. This is not only true for people who have asthma, but for all people who do sports. Gentle forms of physical exercise that can be integrated into daily life can already have a positive effect on your general health too. You can read more about the health benefits of walking here, for example.

There are also lung or asthma sports groups especially for people with asthma. These give you the opportunity to do sports with other people who have the same condition and talk about your experiences.

What medications can be used to prevent exercised-induced asthma?

If your asthma medication has been adapted to your specific situation and you manage your disease well, you are far less likely to have sudden difficulties breathing when doing sports. You can find more information on how to treat asthma with medications in our fact sheet. To read more about what can help when taking long-term medications, click here. You can talk to your doctor if you are not sure whether your medication is optimally adjusted considering the sports you do.

There are two main groups of asthma medication, called controllers and relievers. Controllers (also called preventers) are used in the long-term treatment of asthma to “control” it, and only work slowly over time. Relievers are used for short-term treatment. They can be used before doing physical activity as well as to relieve acute asthma symptoms. For safety reasons, however, is important, to talk to your doctor about how often you can use them on one day.

The following medications can be used before strenuous activities to prevent exercise-induced asthma:

Short-acting beta2 agonists

Short-acting beta2 agonists work quickly. They are inhaled using a puffer to open up the bronchi and make it easier to breathe. Short-acting beta2 agonists can be used just before strenuous physical activities to lower the chances of having an asthma attack. The effect is strongest about 30 minutes after being inhaled and lasts about three to five hours. Short-acting beta2 agonists can also be used to treat acute asthma attacks: they start working after a few minutes and can help you breathe better.

Leukotriene antagonists

This medication, taken in the form of tablets, blocks the effect of leukotrienes. Leukotrienes are chemical messengers that play a key role in the inflammatory response in the airways. The only leukotriene antagonist that is currently available in Germany is the drug montelukast. This can be used on its own as a long-term treatment or directly before strenuous activities to prevent exercise-induced asthma. It is important not to take more than the maximum daily dose of montelukast.

Mast cell stabilizers (cromones)

Mast cell stabilizers are inhaled using a puffer. They reduce allergic and inflammatory reactions by preventing the release of histamine from the body’s cells. Histamine is a chemical messenger that plays a key role in allergic reactions. Cromones can be used as a long-term measure, as well as just before physical activities in exercise-induced asthma, if needed. But they are not as good at preventing exercise-induced asthma as beta2 agonists are. Even when used together with short-acting beta2 agonists, they do not prevent symptoms better than beta2 agonists alone.

Anticholinergics

Anticholinergics affect the nervous system, causing the bronchi to dilate (open up). They can help in exercise-induced asthma, too. But they are not as good at preventing breathing problems as beta2 agonists and mast cell stabilizers are.

It is often not easy to find out which medications best prevent exercise-induced asthma in an individual person. Everyone reacts a little differently to the treatment. So you might have to try out different medications before you know which one can help you best.

Is it not too dangerous for children with asthma to do sports?

The parents and teachers of children who have asthma are often very cautious when it comes to physical activities. Some even hesitate to let their children participate in sports at school because they are scared it might trigger an asthma attack. Extreme caution like this is usually unnecessary, though, and can even have negative consequences.

On the other hand, there is, of course, a risk that a child who has asthma might have an asthma attack while doing sports. So it is important that the child’s physical activities are adapted to his or her individual situation. The people looking after the child, such as the sports teacher, should be informed of the asthma, as well as what they can do in an emergency. Parents can help their child to take their medication properly and make sure that they always have their reliever medication with them. Talk to your child and a doctor to find out which types of sports may be more suitable than others. Of course, it is also important to choose a sport that your child enjoys and is able to do.

Do not be afraid of sports and exercise

For both adults and children: If you manage your asthma well and are prepared for physical activities, there is no reason why you should avoid doing exercise. After all, physical activities and sports not only help you to get more stamina and become physically fitter, they also help you to relax and simply have fun.

Author: Institute for Quality and Efficiency in Health Care (IQWiG)

© IQWiG (Institute for Quality and Efficiency in Health Care)