Impact of climate variability on exercise-induced bronchospasm in adolescents living in a semi-arid region / Influência de alterações climáticas sobre a ocorrência do broncoespasmo induzido por exercício em adolescentes de uma região semiárida

ABSTRACT Objective: To examine the impact of climate variability on the occurrence of exercise-induced bronchospasm in the rainy and dry seasons of a Brazilian semi-arid region. Methods: This sample comprised 82 adolescents aged 15 to 18 years, who were submitted to exercise-induced bronchospasm assessment on a treadmill and outdoors, during the rainy and the dry season. Anthropometric variables, sexual maturity and forced expiratory volume in the first second were analyzed. Air temperature and humidity, decline in forced expiratory volume in the first second (%) and frequency of bronchospasm were compared between seasons using the independent Student's t test, the Wilcoxon and McNemar tests, respectively. The level of significance was set at p<0.05. Results: The mean age was 15.65±0.82 years. Air temperature, air humidity and decline in forced expiratory volume in the first second (%) differed between seasons, with higher air temperature and humidity in the rainy season (29.6ºC±0.1 and 70.8%±0.6 versus 28.5ºC±0.2 and 48.5%±0.6; p<0.05). The decline in forced expiratory volume in the first second (%) was greater in the dry season (9.43%±9.97 versus 12.94%±15.65; p<0.05). The frequency of bronchospasm did not differ between seasons. Conclusion: The dry season had a negative impact on forced expiratory volume in the first second in adolescents, with greater decrease detected during this period. Findings of this study suggested bronchospasm tends to be more severe under low humidity conditions.

RESUMO Objetivo: Verificar a influência das alterações climáticas sobre o broncoespasmo induzido por exercício, nos períodos chuvoso e seco de uma região do semiárido brasileiro. Métodos: Foram submetidos à avaliação do broncoespasmo em esteira ergométrica, em ambiente externo, nos períodos chuvoso e seco, 82 adolescentes, com idades de 15 a 18 anos. Foram avaliadas as variáveis antropométricas, a maturação sexual e o volume expiratório forçado no primeiro segundo. Para comparação da temperatura e umidade, queda do volume expiratório forçado no primeiro segundo (%) e frequência do broncoespasmo entre os períodos, foram utilizados o teste t de Student independente, o teste de Wilcoxon e o teste de McNemar, respectivamente. O nível de significância adotado foi p<0,05. Resultados: A média de idade foi 15,65±0,82 anos. A temperatura, a umidade e a queda do volume expiratório forçado no primeiro segundo (%) diferiram entre os períodos, com valores de temperatura e umidade maiores no período chuvoso (29,6ºC±0,1 e 70,8%±0,6 versus 28,5ºC±0,2 e 48,4%±0,6; p<0,05). A queda do volume expiratório forçado no primeiro segundo (%) foi maior no período seco (9,43%±9,97 versus 12,94%±15,65; p<0,05), e não foi encontrada diferença da frequência do broncoespasmo entre os períodos. Conclusão: O período seco influenciou negativamente no volume expiratório forçado no primeiro segundo de adolescentes, observando maior percentual de queda dessa variável nesse período. De acordo com os achados, propõe-se uma maior gravidade do broncoespasmo induzido por exercício em condições de baixa umidade.

Broncoespasmo induzido por exercício em corredores brasileiros de longa distância de elite / Exercise-induced bronchoconstriction in elite long-distance runners in Brazil

OBJETIVO: Determinar a prevalência de broncoespasmo induzido por exercício em corredores brasileiros de longa distância de elite e se há uma diferença na carga de treinamento entre atletas com e sem broncoespasmo induzido por exercício. MÉTODOS: Estudo transversal com corredores de longa distância de elite sem sintomas atuais de asma e sem diagnóstico de broncoespasmo induzido por exercício. Todos os participantes foram submetidos ao teste de hiperventilação voluntária eucápnica e ao teste cardiopulmonar de esforço máximo e responderam a questionários sobre sintomas de asma e atividade física para monitorizar sua carga de treinamento semanal. RESULTADOS: Dos 86 atletas do sexo masculino recrutados, 20 concordaram em participar do estudo, dos quais 5 (25%) foram diagnosticados com broncoespasmo induzido por exercício. Não foram evidenciadas diferenças entre os atletas com e sem broncoespasmo induzido por exercício em relação a características antropométricas, consumo de oxigênio de pico, valores basais de função pulmonar ou sintomas de asma relatados. A carga de treinamento semanal foi significativamente menor nos atletas com broncoespasmo induzido por exercício do que naqueles sem esse diagnóstico. CONCLUSÕES: Nesta amostra de corredores de longa distância brasileiros, a prevalência de broncoespasmo induzido por exercício foi alta.

OBJECTIVE: To determine the prevalence of exercise-induced bronchoconstriction among elite long-distance runners in Brazil and whether there is a difference in the training loads among athletes with and without exercise-induced bronchoconstriction. METHODS: This was a cross-sectional study involving elite long-distance runners with neither current asthma symptoms nor a diagnosis of exercise-induced bronchoconstriction. All of the participants underwent eucapnic voluntary hyperpnea challenge and maximal cardiopulmonary exercise tests, as well as completing questionnaires regarding asthma symptoms and physical activity, in order to monitor their weekly training load. RESULTS: Among the 86 male athletes recruited, participation in the study was agreed to by 20, of whom 5 (25%) were subsequently diagnosed with exercise-induced bronchoconstriction. There were no differences between the athletes with and without exercise-induced bronchoconstriction regarding anthropometric characteristics, peak oxygen consumption, baseline pulmonary function values, or reported asthma symptoms. The weekly training load was significantly lower among those with exercise-induced bronchoconstriction than among those without. CONCLUSIONS: In this sample of long-distance runners in Brazil, the prevalence of exercise-induced bronchoconstriction was high.

Sensitivity and specificity of self-reported symptoms for exercise-induced bronchospasm diagnosis in children

Exercise-induced bronchospasm [EIB] is a common condition in elite athletes. The purpose of this study was to evaluate the diagnostic value of self-reported EIB symptoms in children. In a cross sectional study in 2005, all soccer player boys of 3 football schools of Shahr Rey a town in the south of Tehran, enrolled in this study. All subjects were asked for the presence of four cardinal symptoms of EIB [cough, wheeze, shortness of breath, chest pain/discomfort] during and after exercise. Self reported symptom-based EIB was defined as having at least two out of four symptoms. Findings were compared to spirometric criteria as a gold standard test. A total of 371 boys were enrolled in this study. The mean age of children was 11.67 +/- 1.53 years [range 7-16 years]. According to spirometric findings, 74 [19.9%] subjects had EIB. The sensitivity and specificity of self-reported symptoms for EIB diagnosis were 13.0% and 89.9%, respectively. Self-reported symptoms of EIB in children can be useful for epidemiological study. Our results in Iran are comparable with studies in other countries and point to a relatively high prevalence of EIB among athlete children

Prevalence of exercise-induced asthma in schoolchildren in Kingston, St. Andrew and St. Catherine, Jamaica

A cross-sectional study was done, focusing on the prevalence of exercise-induced asthma in Jamaica and variables that may account for this rate. No previous study of this nature had been undertaken, and the investigators contend that there is a need to identify children who suffer from this condition but are unaware of it. A sample of 214 students from primary and secondary schools in the corporate area were chosen and given questionnaires to complete. Eighty-four of the children reported a history consistent with that of exercise-induced asthma and were further subjected to stress testing for a definitive diagnosis of this condition. A prevalence of 20.8 per cent [C.I ñ 5.35] was identified which reflected a rate comparable to that recorded in North America. There was a significantly higher prevalence in children of primary school ages, but all other variables considered for significance testing to determine associations between these and the prevalence of EIA proved not significant. A recomendation has been made for opportunity screening by medical practitioners