Asthma is an inflammatory disease of the airways. Although there are multiple known risk factors and triggers, the real cause of asthma still remains unknown. One of the most common triggers in persons with airway obstruction of any kind is physical exercise. If the symptoms of asthma occur during or after exercise, it is called exercise-induced Asthma.
How do exercise-induced asthma symptoms usually appear?
Even if we don’t notice, our breathing is significantly different during exercise. First of all, the body needs a higher amount of oxygen, so the respiratory system tries everything it can to supply the blood with more oxygen. This includes breathing through the mouth rather than through the nostrils, which is particularly bad for asthma patients if the air is very cold. Increased air flow and enhanced circulation in the respiratory system are responsible for triggering asthma attacks.
There are several factors affecting the severity of exercise-induced asthma, such as air temperature, humidity, and the presence of allergens in the air.
Interestingly, the symptoms of exercise-induced asthma rarely appear during exercise, but they suddenly occur several minutes after finishing the exercise.
Is it a separate clinical entity?
The predominant opinion among scientists is – no. Patients who experience asthma symptoms during exercise usually already have a history of asthma. They are either hypersensitive to some allergens or they have some type of non-allergic asthma. It happens very rarely that a person has asthma symptoms only induced by exercise. In those cases, another trigger probably existed, but it is either not present any more or it has not been discovered yet.
How to diagnose exercise-induced asthma?
The diagnosis can usually be assumed by the patient’s report about breathing difficulties after physical activity, but it requires some confirmation. Physical examination is usually normal, as well as laboratory tests. Lung auscultation can show similar findings to those usually heard in asthma patients. Allergy tests often show an allergic reaction to one or more allergens.
However, there are respiratory challenges which can be performed and their results can be impressive in patients with exercise-induced asthma. Here are some of them:
- Treadmill exercise – mimics physical activity and produces symptoms of asthma after exercise.
- Bronchoprovocation test – the subject inhales a small amount of an irritating substance and the results are usually in the form of impaired respiratory volumes
- Eucapnic Voluntary Hyperpnea Test – one of the best tests for exercise-induced asthma. It is designed to get the respiratory system in the state in which it would normally get by performing physical exercise. During this test, the patient inhales a combination of oxygen, carbon dioxide, and nitrogen in specified amounts and hyperventilates for six minutes. The results are measured by spirometry before the test and every 5 minutes after the test for 20 minutes.
Can medications help in this situation?
An attach of exercise-induced asthma is generally treated in the same way as any other type of asthma attack. Bronchodilators, such as beta2-agonists and anticholinergics are most commonly used in the form of asthma inhalers. These attacks can also be prevented by taking a usual dose of bronchodilator right before starting the exercise. During the allergy season, persons with asthma should avoid running in nature and if they do, they should use antihistamine drugs too in order to lower the possibility of an asthma attack.
So is it recommended for people with exercise-induced asthma to engage in sports activities?
Of course. Physical activity is good for the respiratory system because it increases airflow and clears the airways. They should choose the activities which do not stimulate asthma symptoms.
For example, swimming is one of the most commonly recommended sports for asthma patients. Swimming not only increases respiratory volumes, but it also has other benefits. Swimming pools are areas with increased humidity and the air is usually moderately warm. Humidity dissolves the thick mucus, which is present in the airways of persons with asthma. It has been proven that most patients with exercise-induced asthma do not experience any symptoms even after intense swimming sessions.
Are there sports that should be avoided?
Although these are reported experiences of most asthma patients, they vary from case to case. If performed with caution, according to doctor’s advice, no kind of physical exercise should be forbidden to asthma patients. Some patients stop experiencing symptoms if exercises are introduced gradually. Some still need to use inhalers before exercise, but as the respiratory system adjusts to increased physical activity, the need for inhalers becomes less and less.