Overview

Exercised-induced asthma is a narrowing of the airways in the lungs that is triggered by strenuous exercise. It causes shortness of breath, wheezing, coughing and other symptoms during or after exercise.

The preferred term for this condition is exercise-induced bronchoconstriction (brong-koh-kun-STRIK-shun). This term is more accurate because the exercise induces narrowing of airways (bronchoconstriction) but is not the root cause of asthma. Among people with asthma, exercise is likely just one of several factors that can induce breathing difficulties.

For most people with exercise-induced bronchoconstriction, treatment with common asthma medications and preventive measures enable them to exercise and remain active.

Source: http://www.mayoclinic.com

Symptoms

Signs and symptoms of exercise-induced bronchoconstriction may begin during or a few minutes after exercise, and they may persist for 30 minutes or longer if left untreated. The signs and symptoms may include:

• Coughing
• Wheezing
• Shortness of breath
• Chest tightness or pain
• Fatigue during exercise
• Poorer than expected athletic performance
• Feeling out of shape even when you're in good physical shape
• Avoidance of activity (a sign primarily among young children)

When to see a doctor

See your doctor if you experience any signs or symptoms of exercise-induced bronchoconstriction. Because a number of conditions can cause similar symptoms, it's important to get a prompt and accurate diagnosis.

Get emergency medical treatment if you have worsening symptoms:

• Shortness of breath or wheezing that is quickly getting worse
• No improvement even after using a prescription inhaler for asthma attacks

Source: http://www.mayoclinic.com

Causes

Medical researchers are exploring several ideas regarding the cause of exercise-induced bronchoconstriction. There may be more than one biological process that can lead to the condition. Researchers do know that in people who experience exercise-induced bronchoconstriction, strenuous exercise sets in motion molecular events that result in inflammation and the production of mucus in the airways.

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

• Cold air
• Dry air
• Air pollution
• High pollen counts
• Chlorine in swimming pools
• Chemicals used with ice rink resurfacing equipment
• Respiratory infections or other lung disease
• Activities with extended periods of deep breathing, such as long-distance running, swimming or soccer

Source: http://www.mayoclinic.com

Diagnosis

In addition to asking questions about your symptoms, your doctor will conduct a medical exam. He or she will also order tests to assess your lung function and rule out other conditions that may be causing your symptoms.

Test of normal lung function

Your doctor will likely administer a spirometry (spy-ROM-uh-tree) test to assess how well your lungs function when you aren't exercising. A spirometer measures how much air you inhale, how much you exhale and how quickly you exhale.

After you do the test, your doctor may give you an inhaled medication to open your lungs (bronchodilator). You'll repeat the test, and your doctor will compare the results of the two measurements to see whether the bronchodilator improved your airflow. This initial lung function test is important for ruling out underlying chronic asthma as the cause of symptoms.

Exercise challenge tests

An additional test that enables your doctor to observe and assess symptoms is an exercise challenge. You will run on a treadmill or use other stationary exercise equipment that increases your breathing rate. This exercise needs to be intense enough to trigger the symptoms you've experienced. If needed, you might be asked to perform a real-life exercise challenge, such as climbing stairs.

Spirometry tests before and after the challenge can provide evidence of exercise-induced bronchoconstriction.

Alternate challenge tests

As an alternative to the exercise challenge, your doctor may use an inhalation test that simulates the conditions that would likely trigger exercise-induced bronchoconstriction. If your airways respond to these stimuli, then the test should produce virtually the same lung function you have when exercising.

Again spirometry tests before and after the challenge test provide information about changes in lung function. These challenge tests include the following:

• Methacholine challenge, the use of an inhaled agent that interacts with certain smooth muscle cells in airways and results in bronchoconstriction
• Eucapnic voluntary hyperventilation (EVH) challenge, inhaling a mixture of dry air composed of oxygen, carbon dioxide and nitrogen that simulates the exchange of air when breathing is difficult
• Mannitol challenge, inhaling a dry powder that can trigger water loss on the surface of the airways and switch on molecular activity that controls inflammation — conditions that cause bronchoconstriction in people with oversensitive airways

Ruling out other conditions

Your doctor may order additional tests to rule out other conditions with symptoms similar to those of exercise-induced bronchoconstriction. These conditions include:

• Vocal cord dysfunction
• Allergies
• Lung disease
• Irregular heartbeats (arrhythmia) or other heart conditions
• Gastroesophageal reflux disease

Source: http://www.mayoclinic.com

Complications

Exercise-induced bronchoconstriction that is not treated can result in:

• A lack of beneficial exercise
• Poor performance in activities you would otherwise enjoy
• Serious or life-threatening breathing difficulties, particularly among people with poorly managed asthma

Alternative medicine

There is limited clinical evidence of alternative therapies that may modify the severity of exercise-induced bronchoconstriction or provide additional benefit to standard treatments. Possible beneficial interventions include:

• A low-salt diet
• Fatty fish, such as salmon and tuna, or fish oil supplements
• Fruits and vegetables rich in vitamin C (strawberries, oranges, broccoli, leafy vegetables and others) or vitamin C supplements

Source: http://www.mayoclinic.com

Lifestyle and home remedies

Steps you can take to prevent or minimize symptoms of exercise-induced bronchoconstriction include the following:

• Do a 10-minute warm-up that varies in intensity before you begin regular exercise.
• Breathe through your nose to warm and humidify the air before it enters your 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.
• Avoid strenuous exercise if you have a cold or other respiratory infection.
• Exercise regularly to stay in shape and promote good respiratory health.

At school

Talk to your doctor about writing an action plan if your child experiences exercise-induced bronchoconstriction. This document provides step-by-step instructions for teachers, nurses and coaches that explain what treatments your child needs, when treatments should be administered and what to do if your child experiences symptoms.

Source: http://www.mayoclinic.com