EIB is caused by the loss of heat, water or both from the airways during exercise when quickly breathing in air that is drier than what is already in the body. Symptoms typically appear within a few minutes after you start exercising and may continue for 10 to 15 minutes after you finish your workout. Anyone can experience these symptoms (especially someone who is out of shape), but with EIB, they are more severe. Wheezing in children after physical activity is often the first symptom of asthma.
Common symptoms of EIB include:
- Shortness of breath or wheezing
- Decreased endurance
- Tightness in the chest
- Upset stomach
- Sore throat
EIB triggers include airborne irritants related to specific sports. Examples are:
- Chorine when swimming
- Pollution while running or cycling
- Cold, dry air while ice skating or playing hockey
- Air temperature during hot yoga.
When you are working out or competing in a gym, perfume, cleaners, paint, and new equipment or carpet could also be triggers.
While it was thought for years that breathing cold air makes EIB worse, more recent studies indicate that the dryness of the air, rather than the temperature, is more likely the trigger. Cold air typically contains less moisture than warm air, and quickly breathing dry air dehydrates the bronchial tubes, causing them to narrow and restrict airflow.
The sports and activities that are most likely to cause EIB symptoms require constant activity or are done in cold weather. These include soccer, basketball, long-distance running, ice hockey, ice skating and cross-country skiing.
The activities that are least likely to cause EIB symptoms include walking, hiking and recreational biking, or sports requiring only short bursts of activity. These include volleyball, gymnastics, baseball, wrestling, golf, swimming, football, and short-distance track and field sports. Some swimming events can demand constant activity, but the warmth and humidity from the water make it easier for people with EIB to breathe.