What to Know About Exercise-Induced Asthma

Exercise-induced asthma (EIA) refers to bronchoconstriction, the narrowing of bronchi, the main air passages to the lungs, in response to exercise and exertion. A sports-induced bronchoconstriction results in typical asthma symptoms, such as wheezing and shortness of breath.

Exercise-induced bronchoconstriction often involves underlying chronic asthma, with as many as 90% of people diagnosed with asthma having EIA — but not everyone with EIA has asthma.

This article will help you to better understand what causes exercise-induced asthma and manage symptoms. It offers information about when to see a healthcare provider for more severe symptoms.

What Does Exercise-Induced Asthma Feel Like?

The most common symptoms of exercise-induced asthma are characteristic of all forms of asthma:

• Shortness of breath
• Chest tightness
• Chronic cough

In EIA, these symptoms begin during exercise and may become worse 10 to 15 minutes after the activity is stopped. Within 20 to 30 minutes of rest, symptoms usually resolve.

What Causes Exercise-Induced Asthma?

Asthma attacks occur when the muscles of the airways tighten, causing them to narrow. For people with EIA, this bronchoconstriction has to do with moisture and the temperature of the air inhaled during physical exertion.

When you exercise, you tend to take in air more quickly through your mouth than usual. This air is usually colder and drier than air inhaled through the nose, which regulates the temperature and humidity of air before it makes its way to the lungs.

Other factors that can trigger EIA and increase the severity of symptoms include exposure to these conditions while exercising:

• Cold weather
• Air pollution and airborne irritants (e.g., smoke, strong fumes)
• High pollen counts
• A recent cold or asthma episode

Exercise-induced asthma occurs in approximately 5% to 20% of the general population, but the prevalence is higher in children and elite athletes.

How to Know If You Have Exercise-Induced Asthma

If you have already been diagnosed with asthma and begin to show signs of bronchoconstriction after physical activity, your healthcare provider may diagnose EIA based on your symptoms.

However, because exercise-induced asthma symptoms are similar to those of many other disorders, your practitioner may require other diagnostic evaluations including a complete history, physical examination, and results of pulmonary function testing. The same is true if you are presenting with these symptoms and do not have an asthma diagnosis.

Your healthcare provider may use spirometry, a lung function test, to evaluate your breathing before and again after you exercise. For instance, you might be asked to spend time on a treadmill or stationary bicycle while being supervised by a medical professional or technician.

Before you begin, healthcare providers will record your forced expiratory volume (FEV1), the measure of how much air you can exhale during a forced breath. You'll then exercise until you reach 85% of your expected maximum heart rate. Immediately after you stop exercising, your practitioner will measure your FEV1 again.

If it has dropped 10% or more, you're likely to be diagnosed with EIA. The test may be repeated to ensure accurate results.

Before confirming a diagnosis of exercise-induced bronchoconstriction, your healthcare provider may perform additional tests to rule out other causes of your symptoms, such as:

• Gastroesophageal reflux disease
• Rhinosinusitis
• Vocal cord dysfunction
• Obstructive sleep apnea
• Obesity
• Heart failure
• Coronary artery disease

Exercise-Induced Asthma Treatment

EIA is best managed when you work with your healthcare provider to identify, eliminate, and control triggers. For instance, in some cases, you might lower the risk of an episode if you work out indoors or wear a mouth covering when exercising outside in colder weather.

Limiting your exposure to pollution and allergens while you exercise can also help.

Medication

Medication may also be required to manage your symptoms. You and your healthcare provider will work together to choose the most effective preventive and acute treatment options, which will mainly be based on whether or not you have a chronic asthma diagnosis along with EIA.

There are three types of medications that are commonly used to prevent or treat EIA symptoms:

• Short-acting beta-agonists (SABAs): This type of rapid-acting bronchodilator is often called a rescue inhaler. It delivers medication into the airways to quickly open them and stop symptoms if they occur during or after physical activity. Using a SABA 10 to 15 minutes before exercise can help prevent symptoms from occurring during activity as well. The effects should last for up to four hours.
• Long-acting beta-agonists (LABAs): This type of bronchodilator inhaler needs to be used 30 to 60 minutes before activity. The medication is typically used to prevent exercise-induced asthma for 10 to 12 hours, but it doesn't offer quick relief, so it won't stop symptoms once they start. It should be used no more than once per 12 hours.
• Mast cell stabilizers: These drugs prevent blood cells in the immune system called mast cells from releasing histamine and other substances that can trigger asthmatic reactions. The medications should be taken 15 to 20 minutes before exercise to prevent EIA, but they will not relieve symptoms once they have begun.

Antihistamines, generally, are not helpful in treating exercise-induced asthma but there's some evidence that Claritin (loratidine) taken for three days before exercise can decrease symptoms. Leukotriene modifiers like Singulair (montelukast) or Accolate (zafirlukast) may help to prevent exercise-induced asthma from occurring.

Staying Active

While activity is the very thing that triggers exercise-induced asthma, poor physical condition can also increase your incidence of asthma attacks.

Finding safe ways to continue staying physically active can enable you to build muscle strength, boost cardiovascular health, and improve your lung function. These benefits can protect you against future exacerbations, as well as improve your overall health.

You might consider seeking the advice of a personal trainer with experience working with people with asthma so that you can learn activities that can both advance your fitness and keep your EIA under control.

Finally, don't underestimate the importance of warming up. Engaging in about 15 minutes of gradually increasing exercise before an intense exercise session can help prevent or reduce EIA symptoms.

In Case of an Asthma Attack

If asthma attack occurs during physical activity, it's important to act quickly to halt the episode. 

1. Stop all activity and try to stay calm.
2. Get away from or remove any obvious triggers (smoke, dust, cold air).
3. If you have a rescue inhaler, take it.
4. Try to slow or control any erratic breathing.
5. If the symptoms continue, get medical attention quickly.

Asthma symptoms generally come on slowly and increase over time, and they can actually get worse once exercise stops. But with medication and patience, the episode should pass.

Summary

Exercise-induced asthma (EIA) occurs when exercise and exertion lead to bronchoconstriction. This narrowing of the main bronchi moving air to and from the lungs can make it hard to breathe, with symptoms of wheezing and cough. People diagnosed with asthma often experience EIA.

Causes include cold air exposure and a lack of moisture in the airways. Treatment is similar to asthma care, including inhaler use.

Exercise is an important part of staying well, and many successful athletes with EIA continue to play sports by learning how to manage their condition. Avoid EIA causes when possible and use your medication when necessary.

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