Exercise-Induced Asthma (EIA) is a sub-type of asthma where prolonged and vigorous exercise triggers asthma attacks. Like allergies, it affects about 75 percent of asthmatics, so it's quite common. The good news is that it can also be prevented.
Modern evidence suggests that a better term for this is Exercise-Induced Bronchospasm (EIB). This is because exercise is just one of many asthma triggers that may induce an asthma flare-up. It's also because you do not have to have asthma for exercise to cause bronchospasm.
What is it**?**
Exercise, particularly the aerobic kind, like running, may induce a narrowing of the airways called bronchoconstriction or bronchospasm. It occurs when the bronchial muscles wrapped around the airways spasm and squeeze the airways, thus causing them to become narrow. This causes airways to become obstructed, thus making you feel symptoms.
**What are symptoms? **
Common symptoms include:
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Burning, itchy feeling of chest and neck
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Shortness of breath
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Increased mucus production
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Coughing
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Chest tightness
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Fatigue during exercise
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Inability to exercise
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Avoidance of activity (common in children)
**Why does it happen? **
First, keep in mind that during normal breathing air is inhaled through the nose, which warms it to body temperature and humidifies it. While exercising, air is inhaled in rapid, large volumes through the mouth, and may not be adequately warmed and humidified.
Keeping that in mind, experts have theorized that heat and moisture are transferred from airway cells to heat and humidify this air. In susceptible people, this stimulation causes airway cells to release inflammatory mediators, such as histamine and leukotrines. This ultimately leads to bronchospasm and increased mucus production.
Many people with asthma find that this problem is exacerbated when exercising in cold air, such as during the winter time. This is because cold air tends to hold less humidity than warm air.
How might it set you back**?**
In order to avoid symptoms, some people use EIB as an excuse not to participate in aerobic activity. Yet avoidance of aerobic activity causes one to miss out on all the benefits of staying active.
**What are the benefits of exercising? **
The Mayo Clinic lists seven benefits of exercise, and I add a couple more. These are ten reasons why it is essential for EIB to be recognized and prevented.
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Makes your heart and lungs stronger
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Increases your energy level
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Increases your stamina and decreases fatigue
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Helps you sleep better and improve your concentration
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Helps you combat chronic disease
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Improves your mood, confidence and self esteem
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Reduces stress and anxiety
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Improves your immune system, which improves your ability to stave off nasty viruses (the most common asthma trigger) and the flu
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Helps you control weight (Obesity may lead to worsening asthma)
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Makes asthma attacks, when they do occur, less severe
How is it prevented?
The good news is that EIB can be treated and prevented. Generally, there are two methods used.
- EIA. For those who have EIB with asthma, pretreatment with albuterol (usually 2 puffs of the inhaler about 10 minutes prior to exercising) is the most common treatment. However, daily treatment with corticosteroids to reduce and control chronic underlying airway inflammation is also proven to help.
- EIB. For those who do not have typical asthma and only have symptoms with exercise, the best treatment appears to be a pretreatment with albuterol about 10 minutes prior to exercising. Since they are less likely to have chronic airway inflammation, daily treatment with inhaled corticosteroids does not appear to be as helpful.
Another thing that might help is exercising indoors when the air is cold outside. This is because warm air holds more humidity. So the risks of EIB acting up may be less when the air is warmer, such as greater than 50 degrees.
Exercise is essential. Most asthma experts recommend that all people with asthma, regardless of severity, get some form of exercise, including aerobic activity. This is why it is especially important to both recognize and treat EIB.
Further reading
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"Heterogeneity in Asthma," Edited by Allen R. Brasier, 2013, pages 8, 10, 79
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"Exercise Induced Bronchoconstriction," Edited by Sandra Anderson, August, 2013