Exercise in childhood asthma: provoking agent, diagnostic tool and therapeutic measure.

Asthma is one of the most common chronic diseases in pediatrics, with an estimated prevalence of 10–15%. Despite advances in the understanding of the disease and its treatment, in recent years an increase has been noted in its prevalence, severity, morbidity (hospitalizations), and even mortality. Asthma is defined today as a pulmonary disorder characterized by reversible bronchoconstriction, inflammation, and airways hypersensitivity to various stimuli [1]. The main causes of exacerbations in children include viral upper respiratory tract infections, allergens, and physical activity. It is assumed that 50–80% of asthmatic children will suffer from exercise-induced asthma [2]. This is probably an underestimation since, with the "appropriate" (strenuous) activity, the vast majority of patients will experience EIA [3]. In discussing the relationship between asthma and physical activity one must remember that, traditionally, asthmatic patients were limited in, if not restricted from, participation in competitive sports. Today, however, even moderate-to-severe asthmatics are engaging in competitive sports [4]. It is notable that although EIA was detected among 11.2% of the American Olympic team members (67 of 597 athletes) participating in the 1984 Los Angeles Olympic Games, it did not interfere with their achievements and they walked home with 41 medals, 15 of them gold [5]. The relationship between asthma and physical activity is interesting and complex. Whereas physical exertion can exacerbate the disease, prolonged and controlled activity can assist in its management. In addition, physical activity serves as an important diagnostic and research tool. The purpose of this article is to review these interconnections.