Exercise-induced asthma

Picture of three teenagers in a swimming pool (PantherMedia / Benis Arapovic)

Suddenly getting out of breath or gasping for air when doing sports can be frightening. But physical activity is also important in people who have exercise-induced asthma. The key is to find the right balance: Too much can set off an asthma attack, but too little affects your lung performance.

Some children, teenagers and adults who have asthma avoid physical exertion because they associate it with the unpleasant experience of having breathing difficulties. But you can still do sports safely, even if you have asthma. It is important to know how to deal with asthma symptoms and relieve an asthma attack. Medications can help lower the risk of asthma attacks.

If children and adults manage their asthma well and are prepared for strenuous physical activities, there is no reason why they should avoid doing them. Exercise and sports not only help you improve your stamina and become physically fitter, they can also help you to relax and simply have fun. Asthma need not be a barrier to leading an active life.

How does exercise-induced asthma develop?

Many people with asthma will know what it's like to have trouble breathing after doing sports. When physical exertion leads to typical asthma symptoms like breathlessness, it is called exercise-induced asthma. About 70 to 90 out of 100 people with asthma are affected by this.

When we breathe in, our nose cleans, warms and moistens the air. During physical exercise, though, we breathe faster, deeper, and more through our mouth. This means that the air that enters our lungs is colder and drier than usual. The membranes lining the bronchi (lung airway passages) might swell up as a result. In people with asthma, these membranes are very sensitive anyway, and they tend to react very strongly. Cold and dry air can increase this effect. Because of this, people are more likely to have exercise-induced asthma when doing winter sports.

The severity of exercise-induced asthma attacks is influenced by a number of factors, including how intense the exercise is, when it is done, the air temperature and humidity, and whether there are other triggers like pollen in the air. Exercise-induced asthma attacks usually start about five to ten minutes after the physical activity is stopped. They are less common during exercise. The symptoms usually disappear on their own again after about 30 to 45 minutes.

How is exercise-induced asthma diagnosed?

Exercise-induced asthma often first arises in childhood or puberty. Because children and teenagers are very active in general, susceptibility may be detected quite early on due to shortness of breath. It's then a good idea to have things checked out by a doctor, to find out whether it's asthma.

To see whether physical activity triggers asthma attacks, an exercise test is often done. This may involve, for example, getting on a treadmill or exercise bike for several minutes. Other 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 called spirometry. Spirometers are electronic or mechanical devices that measure the amount of air you breathe out and how fast you can blow it out. In this test, you breathe into and out of the spirometer through a tube. Another kind of lung function test involves a device called a peak flow meter. Here you breathe into the device as hard and as fast as you can. The peak flow meter measures how fast you can blow air out of your lungs. These measurements provide information about how narrow your airways are.

Are sports good or bad for people who have asthma?

Physical exercise also has important health benefits for people with asthma. People with asthma who know how to deal with asthma attacks – and how to use medication in order to prevent their symptoms from getting worse – can still do sports. You have to know your own limits, though.

Research suggests that sports and exercise reduce asthma symptoms in the long term. But it's important to choose activities that match your level of fitness. This may mean, for example, taking a break or doing something less strenuous if you notice signs of breathing difficulties. Warming up before doing sports, and gradually increasing the intensity of physical exertion, can help too. Studies also suggest that interval training can prevent exercise-induced asthma. In interval training, high-energy exercise is alternated with periods of rest.

It's important to keep a reliever medication on hand so you can react quickly if you have an asthma attack. Sometimes it may help to use reliever medication before doing exercise. You can ask your doctor for more information and advice.

Are some types of sports more suitable than others?

It's difficult to say whether some types of sports are more “asthma-friendly” than others because there isn't enough scientific research in this area. People with asthma who do outdoor sports need to be aware that cold and dry air is more likely to trigger exercise-induced asthma. This is one of the main reasons why asthma attacks are more common during, for example, winter sports than when swimming, where the air is warm and moist.

Whatever type of sports you do, it's a good idea to increase the intensity step by step. In other words, if you have asthma, it's better to not start off sprinting or lifting heavy weights right away. Starting slowly and warming up properly before more strenuous physical activities is the right approach. If you aren't very fit, you could start off with endurance sports like walking, swimming or hiking. The main thing is that you enjoy whatever you do and it makes you feel good.

There are also special sports groups for people with asthma or lung problems. Here you can train with others who have asthma and learn from each other's experiences.

What medications can prevent exercise-induced asthma?

If your asthma medication has been adapted to your specific situation and you can effectively control your asthma, you are far less likely to have sudden breathing difficulties when you do sports. Your doctor can help you find the type of medication that best suits your physical activities.

There are two main groups of asthma medications, known as controllers and relievers. Controller (“preventer”) medication is used as a long-term treatment to keep the asthma under control. The effect of this medication is felt slowly over time. Reliever (“rescue”) medication has a quick and short-term effect. It can be used before doing strenuous physical activities, as well as to relieve acute asthma attacks. It's important to talk to your doctor about how often you can safely use reliever medication per day.

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

  • Short-acting beta2-agonists are inhaled as a spray and have a fast effect. They cause the airways to relax and open up, making it easier to breathe. When used just before strenuous physical activities, they can prevent asthma attacks. 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: These medications are taken in the form of tablets and block the effect of leukotrienes. Leukotrienes are chemical messengers that play a key role in the inflammatory response in the airways. The leukotriene antagonists currently approved in Germany are called montelukast and zafirlukast. They can be used before strenuous activities to prevent exercise-induced asthma:
  • Mast cell stabilizers (cromones) 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 also plays a key role in allergic reactions. But cromones aren't as good at preventing exercise-induced asthma as beta2-agonists are. Even when used together with short-acting beta2-agonists, they do not work better than beta2-agonists alone.
  • Anticholinergics affect the nervous system, causing the airways to dilate (relax and open up). They are inhaled as a spray and can help in exercise-induced asthma, too. But beta2-agonists and mast cell stabilizers are more effective at preventing exercise-related breathing problems.

It's often not easy to know which medications will best prevent exercise-induced asthma. You may have to try out different medications to find out which medication works best for you.

Are sports dangerous for children with asthma?

The parents and teachers of children who have asthma are sometimes very cautious. Some even hesitate to let their children participate in sports at school because they're scared it might trigger an asthma attack. This caution is usually exaggerated, 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's important to adapt the child’s physical activities to his or her situation. People such as sports teachers should also be told that the child has asthma – and know what to do in an emergency. Parents can help their children to take their medication properly and make sure that they always have their reliever medication with them. You can talk to your child and a doctor to find out which types of sports may be more suitable than others. But it's important to choose a sport that your child enjoys.