A large number of Olympic athletes have asthma, and intense exercise has the potential to alter their sports performances in inducing troublesome respiratory symptoms.^1,2 The prevalence of asthma in Olympic athletes has been reported to be between 9% and 55%.^1–5 It is particularly high in winter sports athletes and in swimmers, and its prevalence has been reported to be increasing. Furthermore, high level training is thought to contribute to the development of airway hyperresponsiveness and symptomatic asthma.^2,3

Although most current asthma medications, including the frequently used inhaled short acting β₂ agonists, do not seem to have performance enhancing effects when used at doses required to prevent or treat exercise-induced bronchoconstriction, their use has been regulated.^6–9 To ensure that they are used for an appropriate diagnosis, the International Olympic Committee-Medical Commission (IOC-MC) has established criteria for a positive diagnosis of asthma. It includes a significant bronchodilator response, or a positive bronchial provocation challenge, a fall in forced expiratory volume in 1 second of at least 10% from pre-challenge measures being required for exercise or eucapnic voluntary hyperpnoea.¹⁰

In this issue of Thorax, Dickinson et al looked at the influence of these recently established criteria on the prevalence of asthma in the British Olympic Team participating to the 2004 Olympic Games in comparison to the year 2000.⁴ In 2000 the diagnosis was established by analysing the pre-Olympic medical forms …