Exercise Induced Asthma

Exercise induced asthma (EIA) is an obstructive airway disease that results in a reduced expiratory airflow during or following exercise. Most people with chronic asthma experience symptoms of asthma during exercise. However, there are many people without chronic asthma who develop symptoms only during exercise. There are a number of triggers that cause EIA such as breathing large volumes of air, dry air, cold air, high pollen count, pollution, presence of chest infection, dust and a chlorine environment such as indoor swimming pool.

When we who are susceptible to EIA, exercise in the presence of these triggers we initiate an inflammatory response that leads to a constriction of the smooth muscle that surrounds the airway. This constriction of airway smooth muscle and inflammation narrows the airway so that airway resistance is increased and expiratory airflow is decreased. Typically this happens most often after short, hard intense exercise but can occur during an endurance race. 

Endurance athletes are more susceptible to EIA than the general population because of the sustained high ventilatory demands of training and competition. During intense training and competition we breathe large quantities of air through our mouth, which requires the lower airways in our lungs to warm, humidify and filter the air. In susceptible individuals this causes an inflammatory process, which leads to the constriction of smooth muscle around the lower airway.

Although symptoms are a poor predictor of EIA, some athletes may experience coughing, expiratory wheeze, excess mucus production, chest tightness and difficulty in breathing. Many athletes may not recognise these symptoms and put a post training cough or tight chest down to simply training hard. Using the symptoms alone to diagnose EIA results in 50 per cent of athletes being misdiagnosed.

A secure diagnosis of EIA should involve an objective airway challenge that demonstrates the presence of an airway obstruction and the reversibility of the obstruction when treated with an inhaler such as salbutamol. Although GP practices can conduct assessments for asthma many practices do not offer assessments for EIA. You may have to ask to be referred to a specialist respiratory consultant in order to gain access to a suitable test.

Before you go to doctor, you may try to spot the difference between EIA and Dysfunctional breathing.

Exercise induced asthma

• Can limit exercise performance but narrowing of the airways typically occurs 5-10 minutes after exercise
• Wheeze on breathing out
• Fall in lung function post exercise
• Sound is primarily from the chest
• Symptoms relieved after inhalation of reliever inhalers

Dysfunctional breathing

• Occurs during intense exercise and resolves within 5 minutes of stopping exercise
• Wheeze on breathing in
• No fall in lung function post exercise
• Sound originates in the neck Symptoms remain after inhalation of reliever inhaler

Prevent The EIA

Asthma inhalers or bronchodilators used prior to exercise can control and prevent exercise-induced asthma symptoms. The preferred asthma medications are short-acting beta-2 agonists such as albuterol. Taken 10 minutes before exercise, these medications can prevent the airways from contracting and help control exercise-induced asthma.

Another asthma treatment that may be useful when taken before exercise is inhaled cromolyn sodium, such as Intal or Tilade,15 to 20 minutes before exercise. Having good control of asthma in general will also help prevent exercise-induced symptoms. Medications that may be part of routine asthma management include inhaled corticosteroids such as Qvar or Pulmicort.

An inhaled long-acting beta-2 agonist combined with a corticosteroid, such as Advair or Symbicort, may be added to the treatment regimen. In addition to taking medications, warming up prior to exercising and cooling down after exercise can help in asthma prevention. For those with allergies and asthma, exercise should be limited during high pollen days or when temperatures are extremely low and air pollution levels are high.

Source:

http://www.webmd.com/asthma/guide/exercise-induced-asthma?page=2

Triathlon Plus, Winter 2016

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