Exercise-induced asthma happens when the airways narrow or squeeze during or after physical activity. It causes shortness of breath, wheezing, coughing and other symptoms during or after exercise.

The medical term for this condition is exercise-induced bronchoconstriction (brong-koh-kun-STRIK-shun). Many people with asthma have exercise-induced asthma. But people without asthma also can have it.

Most people with exercise-induced asthma can continue to exercise and remain active if they treat symptoms. Treatment includes asthma medicines and taking steps to prevent symptoms before physical activity starts.

Symptoms of exercise-induced asthma usually begin during or soon after exercise. These symptoms can last for an hour or longer if untreated. Symptoms include:

• Coughing.
• Wheezing.
• Shortness of breath.
• Chest tightness or pain.
• Fatigue during exercise.
• Poorer than expected athletic performance.
• Avoiding activity, which happens mostly in young children.

See your healthcare professional if you have symptoms of exercise-induced asthma. A few conditions can cause similar symptoms, so it's important to get a diagnosis as soon as you can.

Get emergency medical treatment if you have:

• Shortness of breath or wheezing that is quickly getting worse, making it hard to breathe.
• No improvement even after using a prescription inhaler for asthma attacks.

It's not exactly clear what causes exercise-induced asthma. For a long time, the cause was thought to be cold air. However, recent studies found dry air to be a more likely culprit. Cold air contains less moisture than warm air. Breathing in cold, dry air dehydrates the air passages. This causes them to narrow, reducing air flow. Other factors, such as chlorine or other fumes, can irritate the lining of the airways and contribute to breathing difficulties.

Exercise-induced asthma is more likely to happen in:

• People with asthma. About 90% of people with asthma have exercise-induced asthma. However, it can happen in people who don't have asthma.
• Elite athletes. Although anyone can have exercise-induced asthma, it's more common in high-level athletes.

Factors that can increase the risk of the condition or act as triggers include:

• Dry air.
• Cold air.
• Air pollution.
• Chlorine in swimming pools.
• In a gym setting, fumes from perfume, paint, new equipment or carpet.
• Activities with long periods of deep breathing, such as long-distance running, swimming or soccer.

If not treated, exercise-induced asthma can result in:

• Serious or life-threatening breathing difficulties, particularly among people with poorly managed asthma.
• Lower quality of life because of not being able to exercise.

A healthcare professional might prescribe medicines to take shortly before exercise or to take daily for long-term control.

Preexercise medicines

If a health professional prescribes a medicine to take before exercising, ask how much time is needed between taking the medicine and starting the activity.

• Short-acting beta agonists (SABAs) are the most commonly prescribed medicines to take before exercising. These medicines include albuterol (ProAir HFA, Proventil-HFA, Ventolin HFA) and levalbuterol (Xopenex HFA). SABAs are inhaled medicines that help open airways. Do not use these medicines every day because it can make them less effective.

• Ipratropium (Atrovent HFA) is an inhaled medicine that relaxes the airways and may be effective for some people. A generic version of ipratropium also can be taken with a device called a nebulizer.

Long-term control medicines

A healthcare professional may prescribe a long-term control medicine to manage underlying asthma or to control symptoms when preexercise treatment alone doesn't work. These medicines are usually taken daily. They include:

• Inhaled corticosteroids, which help calm inflammation in the airways. These medicines are taken by breathing them in. This treatment may need to be used for up to four weeks before it will have maximum benefit.
• Combination inhalers, which contain a corticosteroid and a long-acting beta agonist (LABA), a medicine that relaxes airways. These inhalers are prescribed for long-term control, but a health professional may recommend using them before exercise.
• Leukotriene modifiers, which are medicines that block inflammatory activity for some people. These medicines are taken by mouth. They can be used daily or before exercise if taken at least two hours in advance.

  Possible side effects of leukotriene modifiers include behavior and mood changes and suicidal thoughts. Talk to your health professional if you have these symptoms.

Don't rely only on quick-relief medicines

Preexercise medicines may be recommended as a quick-relief treatment for symptoms. However, a preexercise inhaler should not be used more often than recommended.

Keep a record of:

• How many puffs are used each week.
• How often the preexercise inhaler is used for prevention.
• How often the preexercise inhaler is used to treat symptoms.

If you use your inhaler daily or you often use it for symptom relief, your health professional might adjust your long-term control medicine.

Exercise is an important part of a healthy lifestyle for everyone, including most people with exercise-induced asthma. Besides taking medicine, you can try these steps to help prevent or ease symptoms:

• Do about 15 minutes of warmup that varies in intensity before beginning regular exercise.
• Breathe through the nose to warm and humidify air before it enters the lungs.
• Wear a face mask or scarf when exercising, especially in cold, dry weather.
• If you have allergies, avoid triggers. For example, don't exercise outside when pollen counts are high.
• Try to avoid areas with high levels of air pollution, such as roads with heavy traffic.

At school

If your child has exercise-induced asthma, talk with a healthcare professional about providing an action plan. This document provides step-by-step instructions for teachers, nurses and coaches that explain:

• What treatments your child needs.
• When treatments should be given.
• What to do if your child has symptoms.

There is limited evidence that any alternative treatments benefit people with exercise-induced asthma. For example, it's been suggested that fish oil, vitamin C or vitamin C supplements can help prevent exercise-induced asthma, but there isn't enough evidence to show whether they're useful.

You're likely to start by seeing someone on your primary healthcare team. A member of your care team may refer you to someone who specializes in asthma, such as an allergist-immunologist or a pulmonologist.

Be prepared to answer the following questions:

• What symptoms have you had?
• Do they start right away when you start exercising, sometime during a workout or after you exercise?
• How long do the symptoms last?
• Do you have breathing difficulties when you're not exercising?
• What are your typical workouts or recreational activities?
• Have you recently made changes to your exercise routine?
• Do the symptoms happen every time you exercise or only in certain environments?
• Have you been diagnosed with allergies or asthma?
• What other medical conditions do you have?
• What medicines do you take? What is the dosage of each medicine?
• What dietary supplements or herbal medicines do you take?