Exercise-induced bronchoconstriction: prevalence, pathophysiology, patient impact, diagnosis and management

Abstract

Exercise-induced bronchoconstriction (EIB) can occur in individuals with and without asthma, and is prevalent among athletes of all levels. In patients with asthma, symptoms of EIB significantly increase the proportion reporting feelings of fearfulness, frustration, isolation, depression and embarrassment compared with those without symptoms. EIB can also prevent patients with asthma from participating in exercise and negatively impact their quality of life. Diagnosis of EIB is based on symptoms and spirometry or bronchial provocation tests; owing to low awareness of EIB and lack of simple, standardised diagnostic methods, under-diagnosis and mis-diagnosis of EIB are common. To improve the rates of diagnosis of EIB in primary care, validated and widely accepted symptom-based questionnaires are needed that can accurately replicate the current diagnostic standards (forced expiratory volume in 1 s reductions observed following exercise or bronchoprovocation challenge) in patients with and without asthma. In patients without asthma, EIB can be managed by various non-pharmacological methods and the use of pre-exercise short-acting β₂-agonists (SABAs). In patients with asthma, EIB is often associated with poor asthma control but can also occur in individuals who have good control when not exercising. Inhaled corticosteroids are recommended when asthma control is suboptimal; however, pre-exercise SABAs are also widely used and are recommended as the first-line therapy. This review describes the burden, key features, diagnosis and current treatment approaches for EIB in patients with and without asthma and serves as a call to action for family physicians to be aware of EIB and consider it as a potential diagnosis.

Fig. 1

Country-specific prevalence* of EIB in children (general population).^–,– *Owing to differences in study methodology, comparisons between studies should be treated with caution. EIB exercise-induced bronchoconstriction

Fig. 2

Impact of aerobic training on symptomatic burden in patients with moderate or severe persistent asthma. Patients were 20–50 years old with moderate or severe persistent asthma. Patients were under medical treatment for 6 months and considered clinically stable; *p < 0.05 compared with baseline; ^†p < 0.05 compared with baseline and control group (two-way repeated-measure analysis of variance). Control group, n = 45; aerobic training group n = 44. **Time points are 0 days (1 month before treatment), 30 days (first month of treatment), 60 days (second month of treatment) and 90 days (third month of treatment)

Fig. 3

Algorithm for diagnosis of EIB.^,,,, EIB exercise-induced bronchoconstriction, FEV₁ forced expiratory volume in 1 s

Fig. 4

Mean values for forced expiratory volume in 1 s in patients with exercise-induced asthma treated with a short-acting β₂-agonist. Data are expressed as a percentage of the predicted normal value, measured before and 30 min after each treatment and for 15 min after exercise. Crossover study conducted in 27 patients. Reproduced from Anderson et al. (2001) with permission from Wolters Kluwer Health, Inc. DPI dry powder inhaler, FEV₁ forced expiratory volume in 1 s, pDMI pressurised metered dose