Exercise and asthma

Did you know?

For many people with asthma, physical activity can trigger symptoms. This is known as exercise induced asthma (EIA).

There’s no doubt, asthma is a big issue for New Zealanders – we have the second highest prevalence of the condition in the world, second only to the UK. More than 600,000 Kiwis are affected by it, and according to the Asthma Foundation, hospitalisation rates have more than doubled in the past 30 years.

People with the condition have sensitive airways in their lungs, which may tighten, partially close, swell or create more mucus, when faced with certain triggers. This makes it hard to breathe in - and even harder to breathe out.

It can also appear to be an obstacle to exercise, but the good news is that people with asthma who are active usually find they experience fewer symptoms and cope better when they do have them. A recent study found physical activity improved asthmatics’ ability to take up oxygen and improved their breathing.

Tips for exercising with asthma

Exercise Induced Asthma (EIA)

Exercise-induced asthma (EIA) is airway narrowing brought on by vigorous exercise. You may have this condition if exercise makes you feel:

• tight in the chest
• wheezy
• breathless
• like coughing.

The symptoms of EIA 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.

How to find out if you have EIA

Some people only ever get asthma when they exercise and may blame age or fitness for their breathlessness, but a GP can provide you with a peak flow meter. Use it before and after exercise and, if your peak flow rate drops 20% after exercise, then you have EIA.

Your doctor may also 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.

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.

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.

Other preventers that your doctor may suggest are nedocromil (Tilade), sodium cromoglycate (Intal,Vicrom) or leukotriene receptor antagonists, such as montelukast (Singulair).

If your EIA is mild, symptom controllers or relievers may be given on their own. And there is a range of breathing exercises, recommended by The Asthma Foundation, which you can do to help.

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 Angela McMillan, world champion aerobic gymnast and Kiwi swimming icon Danyon Loader.

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. In some people, humidity can trigger asthma.
People with asthma are advised not to SCUBA dive, as it can be dangerous.

Asthma symptoms during exercise - what to do