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.

Can you develop EIB?

EIB is common in people with asthma. But you can still develop EIB even if you don’t have asthma. Understandably, you may want to avoid physical activity if you have exercise-induced asthma. However, regular exercise is beneficial for everyone, even if you have asthma.

Can you develop EIB later in life?

Sometimes, exercise-induced asthma can return up to 12 hours after you’ve finished exercising. They can appear even when you’re at rest. These are called “late-phase” symptoms. It may take up to a day for late-phase symptoms to go away.

This type of narrowing happens during vigorous exercise because you tend to breathe more through your mouth instead of through your nose. This allows cooler and drier air into your lungs, which can trigger the bronchospasm.