Asthma: exercise-induced asthma
Although exercise is a common trigger for asthma symptoms, this does not mean that you should avoid exercise just because you have asthma. On the contrary, exercise has health benefits for people with asthma, as it does for most other people.
What is exercise-induced asthma?
Exercise-induced asthma (EIA) is airway narrowing brought on by vigorous exercise. The symptoms of EIA — wheeze, breathlessness, cough or chest tightness — may start during exercise but usually worsen in the 5-10 minutes after you stop exercising.
Some people with EIA get asthma symptoms only after exercise, while others find that their asthma also occurs in other situations.
What causes EIA?
Exactly how EIA happens is not clear. However, it is thought that EIA may involve loss of heat and water from the airways, as they try to warm and moisten large volumes of incoming cool dry air. The cooler and drier the air you breathe in while you exercise, the more severe the symptoms of EIA. Rapid rewarming of the airways after exercise is also put forward as a cause of EIA.
If you train intensely and frequently, especially in cold dry air, your risk of developing EIA increases. Other factors that make EIA more likely are allergens (substances that can trigger an allergic reaction, such as pollen) or irritants in the environment.
Symptoms during exercise: what to do
If you have asthma symptoms in response to exercise you should:
- stop the exercise and sit upright;
- take 4 separate puffs of your reliever medicine, through a spacer if available, and take 4 breaths after each puff;
- only continue exercising when you can breathe comfortably; and
- warm up properly on returning to exercise.
If symptoms do not settle within 4 minutes, you may need the following emergency first aid treatment for your asthma symptoms.
- Take 4 puffs of your reliever, one puff at a time, with 4 breaths after each puff.
- If there is still no or little improvement, call an ambulance immediately, and continue with the 4 puffs every 4 minutes until help arrives.
- If the asthma attack is severe, adults can take up to 8 puffs of reliever every 5 minutes while waiting for the ambulance.
How to find out if you have EIA
To see whether you have EIA, your doctor may suggest an exercise challenge test — your lung function will be measured before exercise (usually on a treadmill) and repeated several times after exercise.
Other tests are sometimes done to diagnose EIA; some involve inhaling various irritants to see whether your airways react to them.
EIA and children
EIA is common in school-aged children, and many affected children won’t have asthma in other situations. However, bear in mind that asthma may not be the cause of your child’s breathlessness when they exercise — take your child to a doctor for a proper assessment and diagnosis.
If your child has asthma, don’t exclude them from exercise; instead aim for them to have the best possible control of their asthma. Usually this includes your child taking medicine prescribed by their doctor. This can be during asthma episodes only, just before exercise or on a daily basis, depending on how severe the asthma is — ask your doctor for advice.
Improving asthma control
If you get asthma when you exercise, it’s important that your asthma is well controlled. Needing to use your reliever inhaler more than once a day can indicate that your asthma is poorly controlled.
Improved asthma control can reduce EIA, so see your doctor about improving your asthma control so you can participate more fully in an exercise of your choice.
Your doctor may prescribe medicines to prevent EIA. Inhaled corticosteroids (preventers) often effectively reduce the severity of EIA, but they take 2-3 months to have their full effect. You will therefore probably need other medicines during this period and possibly on an ongoing basis. Your doctor may suggest various medicines including long-acting beta2 agonists (symptom controllers) and short-acting beta2 agonists (relievers). Relievers are usually taken just before exercise.
If your EIA is mild, symptom controllers or relievers may be given on their own.
Other preventers that your doctor may suggest are nedocromil (Tilade), sodium cromoglycate (Intal, Intal Forte) or leukotriene receptor antagonists such as montelukast (Singulair) or zafirlukast (Accolate).
The benefits of exercise
If you have asthma, it’s worth persisting with exercise — EIA is less easily triggered when you are fit than when you are unfit. Exercising can improve your heart and lung fitness, even though your lung function tests may not change.
It’s a good idea to start off slowly with exercise though, especially if it’s been some time since you were very active or if you’ve never exercised before. Over time you can gradually increase the intensity and duration of exercise.
Selecting the right exercise for you
Most people who have asthma can play sport, and many elite athletes have achieved acclaim in their chosen sport despite their asthma, including Jana Rawlinson (nee Pittman) and Matt Shirvington.
Intense exercise, such as running, cycling or team sports, is more likely to trigger EIA than less intense exercise such as golf or walking. Swimming can be a mixed blessing — the warm humid air generally reduces the risk of EIA, but some people find their airways react to the chlorine in indoor pools.
People with asthma are advised not to SCUBA dive, as it can be dangerous for them.
Tips for avoiding asthma when you exercise
The National Asthma Council advises the following strategies to help prevent EIA:
- warm up before you exercise;
- keep as fit as possible;
- exercise in an environment that is warm and humid;
- avoid exercising in environments where the air contains a lot of allergens or irritants; and
- try to breathe through the nose or consider using a mask.
Last Reviewed: 11 October 2007
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