Exercise-Induced Asthma

As the name indicates, exercise-induced asthma refers to asthma triggered by strenuous or prolonged physical activity.

Exercise causes typical symptoms of asthma including

• breathing difficulty,
• wheezing,
• coughing.

Vigorous physical activity or increased duration of exercise triggers narrowing of airways. The narrowing is called as bronchoconstriction, and exercise-induced asthma is now more accurately called as exercise-induced bronchoconstriction.

It occurs in 20% of the people who do not have chronic asthma. It is common for people with chronic asthma to develop symptoms of asthma after exercise.

Diagnosis is based on review of history, symptoms, and breathing test. Pre-treatment with medications that are taken before a strenuous activity, and long-term control medications are used in the treatment of exercise-induced asthma. 

In children, the symptoms of exercise-induced asthma appear within 5-10 minutes after starting the exercise and peak after the cessation of the activity.

In most of the cases, the symptoms last for about an hour, but in some people it may persist for more than hours after completion of the exercise. People with this condition feel tired easily during and after the exercise.

Most common signs and symptoms of exercise-induced asthma include

• Coughing
• Wheezing
• Shortness of breath
• Chest pain
• Tiredness during the activity
• Inability to perform an activity at the expected level
• Avoidance of activity

One needs immediate medical attention if the shortness of breath worsens during an exercise.

A chain of events set in by the activity is the main cause of exercise-induced asthma.

A number of factors increase the risk of this type of asthma including

• Cold weather
• Dry air
• Air pollution
• Environmental factors like pollen
• Presence of chlorine in swimming pool
• Certain chemicals
• Infection of lungs and upper respiratory track
• Activities that require deep breathing

The first step in the diagnosis of exercise-induced asthma is the review of symptoms and physical examination.

Other tests are suggested to assess the functioning of lungs and to rule out chances of conditions that have similar symptoms. Lung function is tested using spirometry. It measures the amount of air inhaled and exhaled, and also the rate of these processes. The test is repeated after opening the narrow airways using a bronchodilator.

An exercise test helps in confirming the role of exercise in triggering the symptoms of asthma.

The patient is asked to use the treadmill to see whether the activity is causing asthma. Spirometry is conducted before and after the challenge to look for evidence of exercise-induced bronchoconstriction.

There are other challenge tests that simulate the conditions in exercise-induced asthma. When they respond to the stimuli they produce the same results as that of exercise challenge test.

Some common challenge tests are

• methacholine challenge,
• eucapnic voluntary hyperventilation (EVH) challenge,
• mannitol challenge.

Many other tests recommended during this condition help in ruling out chances of other conditions.

• Lung diseases,
• vocal cord dysfunction,
• allergies,
• arrhythmia,
• gastroesophageal reflux disease

have symptoms similar to that of exercise-induced asthma.

Treatment of exercise-induced asthma helps to reduce symptoms, disease flare ups, and the need for quick relief-inhalers as much as possible.

Pre-exercise medications

Are useful in opening up the narrow passage way for improving breathing. It is prescribed during an asthma attack. Short-acting beta agonists like albuterol and levalbuterol helps to open up the airway within minutes, and relieve the symptoms soon.

Ipratropium is another quick-relief medication that helps to relax the airways and to improve breathing. Care should be taken not to over-use the pre-exercise medications more often than what is recommended.

Preventive medications

Reduce the inflammation of the airways. They have to be taken every day for a long term to prevent flare ups, even when exposed to asthma trigger.

Corticosteroids like

• fluticasone,
• budesonide,ciclesonide

are used as inhalers for long-term.

Leukotriene modifiers are oral medications for long-term protection from symptoms.

• Montelukast,
• zafirlukast,
• zileuton

are commonly prescribed leukotriene modifiers.

Prevention of triggers and risk factors is the standard way of controlling symptoms of exercise-induced asthma.

Only few alternative remedies are safe and effective in controlling the symptoms of exercise-induced asthma.

• Low-salt diet,
• fish oil supplements,
• fruits and vegetables rich in vitamin C

are considered to be good in controlling this asthma. 

Lifestyle modifications are necessary in order to manage the symptoms of exercise-induced asthma.

Many simple steps help in the management of symptoms.

• Regular warm-up,
• avoiding breathing through nose,
• avoiding cold weather

help in controlling the situation.

If the person is prone to allergies, try to avoid allergens as much as possible.

Exercise regularly to maintain a healthy body weight. 

Exercise-induced asthma leads to complications like breathing difficulties, which is potentially fatal.

The patient may not be able to enjoy or perform in exercises.