Is there cardiac autonomic dysfunction in children and adolescents with exercise-induced bronchospasm?

BACKGROUND: The pulmonary impairment in patients with bronchoconstriction induced by eucapnic voluntary hyperpnea(EVH) goes beyond the respiratory system, also impairing autonomic nervous modulation. This study aimed to evaluate the behavior of cardiac autonomic modulation in young asthmatics with and without EIB after the EVH test. RESEARCH DESIGN AND METHODS: A cross-sectional study design using 54 asthmatics(51.9% female), aged between 10 and 19 years, investigated with the EVH test. Forced expiratory volume in one second(FEV1) was measured at 5, 10, 15, and 30 min after EVH. Heart rate variability(HRV) measures of time were assessed pre and 30 min-post EVH. The diagnosis of Exercise-Induced bronchoconstriction with underlying clinical asthma(EIBA) was confirmed by a fall in FEV1 ≥10% compared to baseline. RESULTS: Thirty(55.5%) asthmatics had EIBA. Subjects with EIBA have reduced mean of the R-R intervals in relation to baseline until 15 minutes after EVH. Individuals without EIBA had increased parasympathetic activity compared to baseline(rMSSD) from 5 min after EVH(p < 0.05). This parasympathetic activity increase in relation to baseline was seen in individuals with EIBA after 25 minutes (rMSSD = 49.9 ± 5.3 vs 63.5 ± 7.2, p < 0.05). CONCLUSION: Young asthmatics with EIBA present a delay in the increase of the parasympathetic component after EVH when compared to asthmatics without EIBA.

Can physical exercise assist in controlling and reducing the severity of exercise-induced bronchospasm in children and adolescents? A systematic review.

OBJECTIVE: The aim of this study was to analyze whether physical exercise can contribute to improving the control and severity of exercise-induced bronchospasm (EIB) in children and adolescents. METHOD: This is a systematic review that used PubMed/Medline and Scopus databases as a search source, and using descriptors indexed to DeCS/Mesh. The articles were analyzed in three stages in the selection process. Methodological quality was assessed using the TESTEX scale. RESULT AND DISCUSSION: A total of 5867 articles were filtered in the initial search; however, only eight of these were included after the eligibility criteria. All presented improvements in cardiorespiratory fitness. Only two followed the international EIB diagnostic guidelines. Of these, only one described a reduction in FEV1 and considered that this improvement may influence the EIB response in children and adolescent athletes with a non-asthmatic sample. CONCLUSION: The studies analyzed in this review did not enable drawing a conclusion regarding the influence of physical exercise on EIB in asthmatics. The lack of clinical trials on EIB and physical exercise, as well as the difficulty in methodological standardization for EIB diagnosis evidence the lack of scientific knowledge in this area, serving as a stimulus for researchers to find more consolidated answers.