Keeping Children With Exercise-induced Asthma Active

Abstract

Exercise-induced bronchospasm, exercise-induced bronchoconstriction, and exercise-induced asthma (EIA) are all terms used to describe the phenomenon of transient airflow obstruction associated with physical exertion. It is a prominent finding in children and young adults because of their greater participation in vigorous activities. The symptoms shortness of breath, cough, chest tightness, and wheezing normally follow the brief period of bronchodilation present early in the course of exercise. Bronchospasm typically arises within 10 to 15 minutes of beginning exercise, peaks 8 to 15 minutes after the exertion is concluded, and resolves about 60 minutes later, but it also may appear during sustained exertion. EIA occurs in up to 90% of asthmatics and 40% of patients with allergic rhinitis; among athletes and in the general population its prevalence is between 6% and 13%. EIA frequently goes undiagnosed. Approximately 9% of individuals with EIA have no history of asthma or allergy. Fifty percent of children with asthma who gave a negative history for EIA had a positive response to exercise challenge.6 Among high school athletes, 12% of subjects not considered to be at risk by history or baseline spirometry tested positive. Before the 1984 Olympic games, of 597 members of the US team, 67 (11%) were found to have EIA. Remarkably, only 26 had been previously identified, emphasizing the importance of screening for EIA even in well-conditioned individuals who appear to be in excellent health. The severity of bronchospasm in EIA is related to the level of ventilation, to heat and water loss from the respiratory tree, and also to the rate of airway rewarming and rehydration after the challenge. Postexercise decrease in the peak expiratory flow rate of normal children may be as much as 15%; therefore, only a decrease in excess of 15% should be viewed as diagnostic. EIA is usually provoked by a workload sufficient to produce 80% of maximum oxygen consumption; however, in severe asthmatics even minimal exertion may be enough to produce symptoms. Patients with normal lung function at rest may have severe air flow limitation induced by exercise,10 and as many as 50% of patients who are well-controlled with inhaled corticosteroids still exhibit EIA. A challenge of sufficient magnitude will provoke EIA in all patients with asthma. PHARMACOLOGIC THERAPY: Exercise, unlike exposure to allergens, does not produce a long-term increase in airway reactivity. Accordingly, patients whose symptoms manifest only after strenuous activity may be treated prophylactically and do not require continuous therapy. Most asthma medications, even some unconventional ones such as heparin, furosemide, calcium channel blockers, and terfenadine, given before exercise, suppress EIA. McFadden accounts for the efficacy of these disparate classes of drugs by their potential effect on the bronchial vasculature that modulates the cooling and/or rewarming phases of the reaction. Short-acting -agonists provide protection in 80% to 95% of affected individuals wit...

Determinants of Physical Fitness in Children With Asthma

“…Over time, unpleasant, past experiences may result in a pattern of physical inactivity, leaving the child with maladaptive attitudes toward and less perceived competence in exercise. 1 This study was designed to examine potential determinants of aerobic fitness in children with asthma. The primary hypothesis was that asthma severity would not correlate with physical fitness.…”

“…FVC, forced vital capacity; FEV 1 , forced expiratory volume during the first second; ATS, American Thoracic Society; PC 20 , provocative concentration causing a 20% fall in FEV 1 ; BMI, body mass index. E xercise-induced bronchoconstriction affects a majority of children with asthma, 1 and the resulting unpleasant symptoms may incline the child to refrain from such activity. According to current treatment guidelines, a diagnosis of asthma should not deter a child from physical activity, inasmuch as normal physical activity is a recognized goal of optimal asthma control.…”

3‐Min step test and treadmill exercise for evaluating exercise-induced asthma

“…The prevalence of bronchial asthma in children is around 10%; and 40-90% of these patients have EIA [1,2], a manifestation that is frequently undiagnosed [3]. Exercise challenge testing to evaluate EIA is helpful in the diagnosis and management of asthma and is also important in research studies investigating the efficacy of drug therapy.…”

Peripheral airway involvement in asthma assessed by single-breath SF6and He washout

“…In a previous nitrogen (N 2 ) multiple-breath washout (MBW) study, STROM-BERG and GUSTAFSSON [13] assessed the peripheral airway effects of cold dry-air hyperventilation challenge (CACh) on asthma patients and controls [13]. After the challenge the asthmatic subjects demonstrated not only a fall in FEV1 but also increased overall ventilation inhomogeneity and gas trapping, indicating peripheral airway obstruction [14].Exercise-induced bronchoconstriction (EIB) is a common problem in children and adults with asthma [15,16]. The underlying mechanism of EIB is drying and cooling of the airways due to the increased ventilation necessary during physical exercise [17,18].…”

“…Exercise-induced bronchoconstriction (EIB) is a common problem in children and adults with asthma [15,16]. The underlying mechanism of EIB is drying and cooling of the airways due to the increased ventilation necessary during physical exercise [17,18].…”