What is Exercise-Induced Asthma
Patients who have asthma have narrowing of the airways
causing them to have difficulty moving air out of the
lungs. Chronic asthma is an inflammatory disorder. Most
patients with chronic asthma will have a flare when
they exercise. Other individuals appear to have a flare
of asthma only when they exercise and do not otherwise
have chronic asthma.
What are the symptoms and triggers?
If you have exercise-induced asthma, you may experience
breathing difficulty within 5-20 minutes after exercise.
Symptoms may include wheezing, chest tightness, coughing
and chest pain. Other EIA symptoms include prolonged
shortness of breath, often beginning 5-10 minutes after
Patients with EIA have airways that are overly sensitive
to sudden changes in temperature and humidity, especially
when breathing colder, drier air. During strenuous activity,
people tend to breathe through their mouths, allowing
the cold, dry air to reach the lower airways without
passing through the warming, humidifying effect of the
nose. With mouth breathing - also common in patients
with colds, sinusitis and allergic rhinitis ("hay fever")
- air is moistened to only 60-70% relative humidity,
while nose-breathing warms and saturates air to about
80 to 90% humidity before it reaches the lungs.
In addition to mouth-breathing, air pollutants, high
pollen counts, and viral respiratory tract infections
can also increase the severity of wheezing with exercise.
To confirm a diagnosis of EIA, a physician:
1. Obtains a patient history.
2. Performs a breathing test when the patient is at
rest to ensure that
the patient does not have chronic
3. Often may perform a breathing test after exercise.
Measurement can be done in a medical
facility or "on the field." In the office setting, a
patient exercises for six to eight minutes using a treadmill
or cycle to create enough exertion to maintain a heart
rate at 80-90% of the age-related maximal predicted
value. The patient breathes into a breathing machine
called a spirometer, which processes the patient's ability
to breathe out, or expire air. This test is performed
before exercise and at various intervals from two to
30 minutes after exercise stops. A decrease of at least
12-15% in the volume of air blown out (as compared to
the starting value) by the patient in one second (termed
the forced expiratory value in one second, or FEV 1)
indicates possible EIA.
On the field, expiratory airflow can be evaluated before
and after a six- to eight-minute "free run" or after
participation in a sport or activity that usually induces
respiratory symptoms. Airflow is again measured for
30 minutes after exercise ends. Although a portable
spirometer can be used, physicians often recommend a
small, relatively inexpensive peak flow meter to demonstrate
the characteristic post-exercise decrease in expiratory
airflow. In this case a 15-20% decrease is required
for the test to be considered positive for EIA.
Although the type and duration of recommended activity
varies with each individual, some activities are better
for those with EIA. Swimming is often considered the
sport of choice for asthmatics and those with a tendency
toward bronchospasm because of its many positive factors:
a warm, humid atmosphere, year-round availability, toning
of upper body muscles, and the way the horizontal position
may help mobilize mucus from the bottom of the lungs.
Walking, leisure biking, hiking and free downhill skiing
are also activities less likely to trigger EIA. In cold
weather, wearing a scarf or surgical mask over the mouth
and nose can decrease symptoms by warming inhaled air.
Team sports that require short bursts of energy, such
as baseball, football, wrestling, golfing, gymnastics,
short-term track and field events or surfing are less
likely to trigger asthma than sports requiring continuous
activity such as soccer, basketball, field hockey or
long-distance running. Cold weather activities such
as cross-country skiing and ice hockey are also more
likely to aggravate airways. However, many asthmatics
have found that with proper training and medical treatment,
they are able to excel as runners or even basketball
Sports that are less likely to trigger EIA:
Sports that require continuous activity or are cold weather
activities are more likely to trigger EIA:
- Leisure biking
- Free downhill skiing
- Team sports that require short bursts of energy
o Short-distance track and field events
- Field hockey
- Long-distance running
- Cross-country skiing
How can EIA be treated?
If you think you have exercise-induced asthma, you should
be seen by a physician to make the proper diagnosis.
For the majority of patients, a short-acting
beta2-agonist inhaled 5 to 30 minutes before exercise
(preferably as close to the start of exercise as possible)
will ease attacks. Also you should warm up for 6-10
minutes before you begin your full exercise program.
When appropriate, you may also be directed by your physician
to use long-term controller medications (for example,
an inhaled steroid or a type of drug called a leukotriene
modifier). Many of the same drugs that are used to treat
asthma are used to treat exercise-induced asthma.
What are some of the myths of EIA?
- If you have EIA, you cannot participate in sports.
- You can't become an elite athlete if you have EIA.
- Only people who have chronic asthma have EIA.
These ideas are simply not true. Exercise
is good for people with EIA, as long at they take proper
precautions. Because cold and dry conditions often worsen
asthma, cross-country skiing is probably not a good
choice of exercise. However, swimming is an excellent
sport for people with EIA. Many elite athletes, including
Olympic champions, have a history of asthma. About 4-7%
of the population is reported to have asthma and most
have EIA. Moreover, additional groups of people have
EIA who do not otherwise have chronic asthma.
Does exercise commonly cause death in patients with
No. Death is extremely rare in this setting. Although
some very high profile athletes have been reported to
die after an asthma attack this is extremely uncommon
and should not dissuade anyone from participating in
sports. What type of doctor should I see if I have EIA?
Allergist/immunologists are knowledgeable and effective
in diagnosing and managing this condition. Allergists
are very skilled at evaluating triggers for asthma including
exercise and other substances in the air. However, in
difficult to diagnose cases, a multi-disciplinary approach
may be needed. This includes the care by a pulmonologist,
an otolaryngologist (ENT), and an allergist/immunologist.