Asthma in adolescent athletes

Abstract

Athletes active in endurance sports are at an increased risk of acquiring asthma through their sports activities, especially so for cross-country skiers, biathlon skiers, swimmers and athletes of other endurance sports. Asthma may be present from early childhood or develop while in active sports. This article focuses on the physical activity and sports activities in children and adolescents. Exercise-induced asthma (EIA) is found in 8-10% of a normal child population of school age and in about 35% of children with current asthma. EIA is caused by the markedly increased ventilation during exercise, with increased heat and water loss through respiration, leading to bronchial constriction. The risk of developing asthma in the young athlete is related to the repeated daily training activity with increased epithelial damage of the airways, delayed repair due to the daily repetition of the training and increased airway mucosal inflammation. The increased environmental exposure through the sports activity to environmental agents, such as cold, dry air in skiers and chlorine compounds in swimmers, increases symptoms and signs of asthma and bronchial hyper-responsiveness, either worsening an existing asthma or leading to a novel disease in a previously healthy athlete. Several specific aspects of daily training life, environmental exposure, diagnostic procedures and aspects of treatment related to the regulations of medication use in sports need particular attention when addressing the adolescent athlete with respiratory symptoms.

Exercise training in children with asthma: a systematic review

“…It is likely to be caused by an increased ventilatory rate as a result of physical exercise 9. According to the osmotic theory, the inhalation of an increased volume of dry air requires humidification, which leads to the loss of water from the respiratory mucosa 10 11. This loss of water from the respiratory mucosa causes an increase in osmolarity in the airway surface, which in turn leads to the release of bronchoconstricting mediators from inflammatory cells such as eosinophils and mast cells 10–14.…”

“…These mediators, for example histamine, prostaglandins and leukotrienes, interact with effector cells (eg, smooth muscle cells) which can cause a transient bronchoconstrictive response 10 12 15. A second theory, the thermal theory, states that vasoconstriction during exercise due to inhalation of the relatively cold and dry air followed by rapid rewarming after exercise, leads to a rebound vasodilatation 11. This results in a reactive hyperaemia of the bronchial microvasculature and oedema of the airway wall which causes airway obstruction 12 15 16.…”

Time spent in vigorous physical activity is associated with increased exhaled nitric oxide in non‐asthmatic adolescents

“…Conversely, elite endurance athletes are at risk of asthma, bronchial hyperresponsiveness (BHR) and increased airway inflammation (3). Presently, the most probable explanation for this phenomenon is bronchial epithelial damage with resulting airway inflammation (4), possibly combined with increased parasympathetic activity (5), inflicted by the increased ventilation because of regularly repeated intensive exercise (6). In healthy subjects, intensive exercise for prolonged periods could result in an airway response similar to that of elite athletes (7), as previously found in bronchial biopsies of young ski gymnasts (8).…”

Prevalence of asthma and respiratory symptoms among cross-country skiers in early adolescence

“…Adult cross-country skiers are especially prone to having asthma and exercise-induced asthma, and this is assumed to be caused by repeated and intense breathing of dry and cold air [4]. In a recent cross-sectional postal questionnaire study, the asthma prevalence was estimated to be 29-35% in Swedish young adults aged 15-19 years and adult crosscountry skiers [5].…”