VIENNA – Up to one in four sudden deaths in top athletes may be asthma related. Athletes are often inadequately treated, as they fear being accused of doping: “Many drugs are used for both the treatment of allergic diseases and doping”, according to Professor Jean Bousquet of Montpellier University, France, speaking at the 19th Annual Congress of the ERS.

Many top athletes, in particular those practicing winter sports or endurance summer sports, suffer from either exercise-induced bronchoconstriction or acute exacerbations of pre-existing asthma, explains Professor Bousquet. Asthma in athletes may well be different from asthma seen in the general population. In swimmers, for example, it has been directly linked to chlorine exposure.

In skiing athletes, different histological features such as lymphoid aggregates have been described. Asthma in athletes may occur later in life than in the general population.

Asthma kills athletes

The public awareness of deaths due to cardiac problems in top athletes is high. However, it is less known that out of 263 fatalities over a 7-year study period in athletes, one in four deaths were asthma related. Sudden fatal asthma exacerbations occur in both competitive and recreational athletes and can be precipitated by sporting activity.

“Special attention is required in athletes who suffer from allergic diseases and asthma with regard to doping issues.”

“A drug that has been abused in the past by athletes is clenbuterol, an oral beta-2 agonist that increases muscle mass in animals and reduces apoptosis.”

Inhaled beta-2 agonists such as salbutamol or salmeterol, however, the mainstay of asthma treatment today, do not increase muscle mass nor enhance performance.

The International Olympic Committee Medical Commission (IOC-MC) requires athletes to provide the result of an objective test to support a diagnosis of asthma or exercise-induced bronchoconstriction (EIB) in order to be permitted to use a beta-2-agonist. For the diagnosis of asthma or EIB, values obtained at lung function tests are not really meaningful: “A normal FEV1 does not exclude asthma”. Further tests such as the metacholine challenge test or the eucapnic voluntary hyperventilation test are required.

The management of the athlete with asthma should follow current guidelines (e.g. Global INitiative for Asthma – GINA) with treatment individualised to achieve optimal asthma control and with the effects of treatment monitored. Currently, there is no evidence that management of asthma in athletes should differ from that in non-athletes. However, some specific issues need to be considered for the high-level athlete.

The prevention and management of exercise induced bronchoconstriction is a key issue in athletes. They may also be exposed to high levels of allergens and environmental irritants during training and competition. Dry and/or cold air may be a particular problem for some athletes. The non-pharmacological management of asthma in athletes is equally important. This includes identifying and reducing exposure to asthma triggers whenever possible and especially during training.

Any medications prescribed must comply with World Anti-Doping Agency (WADA) in accordance with the relevant section of the Therapeutic Use Exemption (TUE) Standard. Inhaled corticosteroids are the most effective drugs for long term control of asthma and prevention of EIB.

Inhaled ß2 agonists are the most effective drugs for immediate inhibition of exercise induced bronchoconstriction and for relieving intermittent symptoms of asthma. However, when used frequently, tolerance (tachyphylaxis) may develop. Athletes who use either short- or long-acting ß2-agonists on a daily basis should be advised that their effectiveness to prevent EIB will partially diminish.

Frequent use of ß2 agonists may also increase the bronchoconstrictor response to exercise and allergens. Strategies to avoid these problems could include restricting ß2 agonists to infrequent use, use of alternative treatments for preventing EIB and ensuring adequate treatment of underlying asthma with inhaled corticosteroids. As for all asthmatic patients, long acting ß2 agonists should not be used as monotherapy.

Picture credit: Wikimedia Commons

2009, week 42