Exercise-induced asthma
The trachea is the main breathing tube or airway which branches into smaller breathing tubes called bronchi which deliver air in and out of the lungs. Exercise-induced asthma is a condition in which strong physical activity triggers tightening of the small breathing tubes making it difficult for air to be released from the lungs. Exercise-induced asthma is often diagnosed in children because of their high level of activity, but can happen at any age.
How it occurs
The cause of exercise-induced asthma is not fully understood. One theory is that faster breathing with exercise makes it difficult for the breathing tubes to keep enough moisture and heat inside. This aggravates the lining of the airways and causes tightening. Cold and dry conditions tend to make symptoms worse.
Exercise-induced asthma is thought to happen in 5 to 20% of the general population. Individuals with asthma are at higher risk for exercise-induced asthma. In competitive athletes, symptoms tend to be more likely with winter and summer endurance sports. Some sports such as swimming and ice skating may expose the athlete to chemicals which can also trigger symptoms.
Signs and symptoms
The athletes may experience coughing, wheezing, chest tightness, shortness of breath and/or increased mucus several minutes after they begin exercise. Some patients notice poor performance, feel tired or feel out of shape even though they are very fit. Symptoms generally occur within 5 to 30 minutes of intense exercise any may get better after 30 minutes. Symptoms tend to be worse with more intense activity.
Diagnosis
The doctor must take a full history and perform a physical exam to diagnose exercise-induced asthma. He or she may also recommend lung function testing to help make the diagnosis. This type of testing involves measuring the athlete's ability to blow air out of the lungs before and after taking a medication to help relax the breathing tubes. The person performing the test may ask that some exercise be performed to bring on the symptoms.
Treatment
The best way to treat exercise-induced asthma in athletes is by preventing the onset of symptoms with medications and proper warm-up. Athletes should warm up for 15 to 20 minutes prior to play with stretching and calisthenics to reach 50 to 60% of maximum heart rate. An inhaled medicine, such as Albuterol, can be used before exercising to help open up the airways and prevent them from closing. Some athletes require other medications, taken by mouth, to help control symptoms; this is especially true for athletes with regular asthma AND exercise-induced asthma. Wearing a mask during cold weather may decrease symptoms. Athletes who notice specific factors that aggravate asthma (such as recently mowed grass) should avoid these triggers.
Returning to activity and sports
Generally children can continue to participate in all activities. Coaches and trainers should be aware of the diagnosis so that they can double-check that children have their medications at each practice session and competition. The coaches should know to stop the exercise if symptoms persist despite treatment. Talk to your child's doctor if symptoms continue despite treatment.