Challenges in the Management of Exercise-induced Asthma

William Storms, MD

Expert Rev Clin Immunol. 2009;5(3)

Pathophysiology of EIA & EIB

An underlying pathology of asthma is airway inflammation. While the mechanism is not completely understood, in the patient with EIA, the airway physiological response to exercise triggers or exacerbates the underlying inflammation of asthma.^[1,3]

Evidence indicates that alterations in airway humidity and temperature contribute to EIA. Vigorous physical activity is associated with increased inhalation by frequency and volume; the increased ventilatory rate results in evaporative changes affecting the respiratory mucosa. This airway drying leads to increases in the osmolarity of respiratory epithelial cells and subsequent inflammatory changes, including the activation of epithelial cells and airway mast cells, and the release of histamine, leukotrienes and other chemokines. Additionally, vascular dilation of small blood vessels involved in rewarming the airways following exercise may contribute to congestion and further release of inflammatory mediators.^[3,8] In patients who have asthma, these changes in airway osmolarity and temperature are believed to trigger the characteristic symptoms of BHR. Increased levels of airway inflammatory cells and mediators have been observed in exercising athletes with and without BHR.^[9,10]

Exercise-induced changes in airway function are exacerbated in cold and/or dry air, possibly reflecting the involvement of additional physiologic pathways (e.g., cholinergic stimulation, pulmonary vasoconstriction and secondary reactive hyperemia).^[4,8]

1 2 3 4 5 6 7 8 9

Next Section

Cite this: Challenges in the Management of Exercise-induced Asthma - Medscape - May 01, 2009.

Table 1. Challenge tests for exercise-induced asthma and exercise-induced bronchospasm.
Indirect	Direct
Adenosine monophosphate^*	Carbachol^*
Eucapnic voluntary hyperventilation	Histamine^*
Mannitol^‡	Methacholine
Hypertonic saline

^*Not accepted by the International Olympic Commitee Medical Commission.
^‡Currently in review by the US FDA, although not yet approved.
Data from [1,6,7,13].

Box 1. Exercise-induced asthma or exercise-induced bronchospasm?
Exercise-induced bronchospasm is bronchospasm that occurs with exercise in a patient who has no evidence of asthma, based on current asthma management guidelines: Normal pulmonary function tests at rest No symptoms with normal activities of daily living No need to use β₂-agonists (other than with exercise) Good Asthma Control Test score (or other questionnaire)
Exercise-induced asthma is bronchospasm that occurs in a patient who has documented persistent asthma, when they exercise

Data from [1-3].

Box 2. Some atypical symptoms of exercise-induced asthma (and exercise-induced bronchospasm).
Complaints of chest pain not associated with cardiac disease 'Locker room cough' or a dry cough lasting up to a day following exercise Difficulty sleeping related to nocturnal asthma symptoms that may be a manifestation of late-phase responses to exercise or physical activity Complaints of 'heavy legs' or 'feeling out of shape' Fatigue Abdominal pain Headaches or dizziness Muscle cramps Seasonal fluctuations of symptoms following exercise related to changes in humidity and levels of airborne allergens and pollutants Avoidance of activities, exercise and/or sports; children may not want to participate in 'sleepovers' or go to 'camp' Inability to keep up with peers Symptoms in children while playing (especially in relation to other triggers, such as animal dander, house dust mites, mold, tobacco and other smoke, and cold air)

Data from [1,3].

Comments

Commenting is limited to medical professionals. To comment please Log-in.

Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.