Exercise-induced asthma affects between 4-7% of the general population and about 80% of diagnosed asthma sufferers.  Asthma is characterised by a reversible narrowing of the airways.  In exercise-induced asthma the narrowing occurs in response to exercise.  A narrowing of the airways during exercise is the direct opposite to the desired response to increased activity.

The narrowing is caused by; swelling of the membrane lining the bronchi and bronchioles (airway tubes); increased mucus production within the airways; and bronchoconstriction (contraction of the muscles surrounding the lungs).

The symptoms of exercise-induced asthma usually occur a few minutes following exercise, or during a period of cool down following a more intensive bout of exercise.  The main symptoms are a cough, chest tightness, shortness of breath and fatigue.  Athletes suffering with exercise induced asthma find it very difficult to increase their fitness and often suffer more in cold weather or, where their condition is associated with allergies, when the pollen count is high.

Exercise induced asthma is diagnosed by your doctor based on your history and on your lung function tests, which may be ordered if the diagnosis is suspected.  Physical examination of the patient at rest is usually unremarkable.  Once diagnosed, the condition can be managed in much the same manner as regular asthma is.  Face masks which allow an athlete to re-breath humidified warm air are one possible non-pharmacological intervention, as well as changes to warm-up and cool down routines.  Corticosteroids may be prescribed by a doctor if the condition is exacerbated during by a chest infection.  Otherwise bronchodilators (inhalers) effectively manage the symptoms of the condition day to day.