Dynamic Hyperinflation Impairs Cardiac Performance During Exercise in COPD.

PURPOSE: To investigate the correlation between a plateau in minute ventilation (Equation is included in full-text article.)E during cardiopulmonary exercise tests (CPETs) and its impact on cardiac performance. METHODS: This retrospective study analyzed 2575 CPETs of patients with chronic obstructive pulmonary disease. The study randomly selected 10 patients with a plateau in the (Equation is included in full-text article.)E curve, suggesting dynamic hyperinflation, 10 patients with normal pattern for the (Equation is included in full-text article.)E curve, and 10 healthy persons. Classic CPET variables, the new ventilation hyperinflation index, and the dynamic cardiac constraint index were analyzed. RESULTS: The patients with dynamic hyperinflation presented with lower ventilation at 100% work rate (P < .0001), without significant differences in (Equation is included in full-text article.)E at 50% and 100% work rate. Patients with dynamic hyperinflation also presented with a lower oxygen pulse (O2 pulse) at 100% (P < .0001), without significant difference in O2 pulse at 50% and 100% work rate. The subjects with dynamic hyperinflation had a higher ventilation hyperinflation index (P < .0001) and dynamic cardiac constraints index (P < .0001). The ventilation hyperinflation index correlated with the dynamic cardiac constraints index (r = 0.81, P < .0001); oxygen pulse variation (r =-0.63, P < .001); (Equation is included in full-text article.)E/(Equation is included in full-text article.)CO2 slope (r =-0.57, P < .01); work rate (r =-0.86, P < .0001); (Equation is included in full-text article.)O2 (r =-0.80, P < .0001), and (Equation is included in full-text article.)E (r =-0.83, P < .0001). CONCLUSION: There is a correlation between a plateau in the (Equation is included in full-text article.)E during CPET, suggesting hyperinflation, and it has an impact on cardiac performance.

Overweight effect on spirometric parameters in adolescents undergoing exercise.

OBJECTIVE: To evaluate effects of overweight on spirometric parameters in adolescents who underwent bronchial provocation test for exercise. METHODS: We included 71 male adolescents. The diagnosis of asthma was done based on participants' clinical history and on the International Study Questionnaire Asthma and Allergies in Childhood, and the diagnosis of obesity was based on body mass index above 95th percentile. The bronchospasm induced by exercise was assessed using the run-walk test on a treadmill for eight minutes. The decrease in forced expiratory volume in one second > or equal to 10% before exercise was considered positive, and to calculate the intensity in exercise-induced bronchospasm we measured the maximum percentage of forced expiratory volume in one second and above the curve area. Data analysis was carried out using the Mann-Whitney U test and Friedman test (ANOVA), followed by Wilcoxon test (p<0.05). In addition, we used Fisher's exact test to analyze the exercise-induced bronchospasm frequency. RESULTS: Significant differences were observed among obese adolescents in exercise-induced bronchospasm frequency (p=0,013) and in relation to time required for recovery after exercise (p=0,007). CONCLUSION: Overweight can influence the increase in the exercise-induced bronchospasm frequency in non-asthmatic adolescents compared with eutrophic adolescents. OBJETIVO: Avaliar o efeito do excesso de peso sobre parâmetros espirométricos em adolescentes submetidos ao teste de broncoprovocação por exercício. MÉTODOS: Participaram do estudo 71 adolescentes do sexo masculino. O diagnóstico de asma foi obtido por meio de histórico clínico e do questionário International Study of Asthma and Allergies in Childhood, e o de obesidade, pelo índice de massa corporal acima do percentil 95. Para avaliar o broncoespasmo induzido pelo exercício, utilizou-se o teste correr/caminhar em esteira ergométrica, com duração de 8 minutos, considerando positivo se diminuição do volume expiratório forçado no primeiro segundo >10% do valor pré-exercício e, para a intensidade do broncoespasmo induzido pelo exercício, foram utilizados o cálculo da queda percentual máxima do volume expiratório forçado no primeiro segundo e a área acima da curva. A análise dos dados foi realizada pelo teste U Mann-Whitney e pela ANOVA de Friedman, seguido do teste de Wilcoxon (p<0,05). O teste de Fisher foi empregado para analisar a frequência de broncoespasmo induzido pelo exercício. RESULTADOS: Foram encontradas diferenças significativas quanto à frequência de broncoespasmo induzido pelo exercício (p=0,013) e ao tempo de recuperação pós-exercício (p=0,007) nos adolescentes obesos. CONCLUSÃO: O excesso de peso pode influenciar no aumento da frequência de broncoespasmo induzido pelo exercício em adolescentes não asmáticos, quando comparados a eutróficos.

Effect of exercise-induced bronchospasm and parental beliefs on physical activity of asthmatic adolescents from a tropical region.

BACKGROUND: Physical activity (PA) is an essential health promotion factor. In asthmatic children and adolescents, exercise-induced bronchospasm (EIB) and parental beliefs and attitudes toward PA may be limiting issues. OBJECTIVE: To compare PA levels in asthmatic adolescents with and without EIB and the influence of mothers' beliefs of asthma worsening due to PA and attitudes in restraining their children's PA, asthma severity, severe EIB, or bronchospasm perception. METHODS: We performed a cross-sectional, hypothesis-testing study from December 1, 2008, through August 31, 2009, using the International Physical Activity Questionnaire to assesses PA levels in 134 asthmatic adolescents (10-19 years of age, 60% male) from an underprivileged community. EIB was defined as a decrease in forced expiratory volume in 1 second greater than 10% from basal 5, 15, or 30 minutes after treadmill running for 8 minutes. Subjective factors were evaluated through specific questionnaires. RESULTS: EIB was diagnosed in 46% of patients and was not associated with lower PA levels (odds ratio, 1.62; 95% confidence interval, 0.75-3.52). The other factors evaluated were also not associated with lower PA levels, although 78% of the mothers said they believe asthmatic children cannot participate in PA as much as nonasthmatic children, 44% that exercise can be harmful, and 52% that they restrained their children's PA. CONCLUSION: We found no association between EIB and low PA levels, although EIB was a frequent event that should be addressed by health care professionals, along with mother's beliefs and attitudes toward PA.