The athlete's guide to exercise-induced asthma

From those who enjoy a casual weekend workout to professional athletes, all types of sports people experience exercise-induced asthma. They include world-class stars like Manchester United’s Paul Scholes, record breaking marathon runner Paula Radcliffe and Olympic relay gold medallist Marlon Devonish.

But just what is exercise-induced asthma, why does it happen, and how can it be managed?

We consulted the experts to find out the answers to these questions, as well as tips for controlling symptoms of exercise-induced asthma, whether you're a casual sports person or a superstar.

What is exercise-induced asthma?

Many people who never experience asthma symptoms at other times have exercise-induced asthma, experts say.

"Exercise-induced asthma occurs in almost everyone who has chronic asthma, but there is a separate group of people who have what we call exercise-induced bronchospasm", says Dr. Timothy Craig of the American Academy of Allergy, Asthma and Immunology (AAAAI).

These people, he explains, don't have what is considered "true" asthma. They don't have inflammation in their lungs. Nor do they experience symptoms when exposed to common triggers, like animals, pollen or mould.

"So unlike most people who have asthma and get exercise-induced symptoms, these individuals don't have true asthma, but when they exercise, they experience the symptoms of asthma", Dr Craig, chair of the AAAAI’s Sports Medicine Committee, says.

Exercise-induced asthma occurs when the airways narrow, making breathing difficult. Why some sports people have exercise-induced asthma and others don't isn't entirely clear.

"The causes vary, but are usually associated with loss of heat or water, or both, from the lungs during exercise, because of the increased ventilation of dry and cool air", says Michael G. Miller, of the US National Athletic Trainers Association.

People with exercise-induced asthma have airways that are overly sensitive to sudden changes in temperature and humidity, especially when breathing colder, drier air, according to Asthma UK.

During strenuous activity, people tend to breathe through their mouths. Mouth breathing allows cold, dry air directly into the lungs, without the benefit of the warmth and moisture that nose breathing supplies. As a result, air is moistened to only 60-70% relative humidity. Nose-breathing, meanwhile, warms and saturates air to about 80 to 90% humidity.

The symptoms of exercise-induced asthma are similar to those of chronic asthma, explains Michael Miller. They include:

• Shortness of breath.
• Tightness in the chest.
• Coughing or wheezing.
• Decreased performance.

These symptoms usually begin after several minutes of exercise and peak about 10 minutes into a workout, or sooner.

Preventing and treating exercise-induced asthma

How can these symptoms be prevented and treated, so asthma doesn't become an excuse to avoid exercise?

Here are some tips for reducing the symptoms of exercise-induced asthma:

• Warm up before working out. “A proper warm-up for at least 10 minutes with a gradual increase in intensity can help prevent symptoms" says Michael Miller.
• Take precautions when it's chilly outside. “If it's cold, cover your mouth and nose to warm the air", says Michael Miller. Or "move to indoor areas that are well-ventilated and have humidified, warm air".
• Use an inhaler. Inhalers containing salbutamol or terbutaline, a beta-agonist bronchodilator, are required. This class of drugs is effective in 80% to 90% of people with exercise-induced asthma. As a preventive therapy, it should be taken about 15 minutes before exercise. The effects can last for up to four to six hours. Your inhaler can also be used to relieve asthma symptoms after they flare.

If warming up and using a beta-agonist does not prevent symptoms, there may be more to your exercise-induced asthma than you think.