Determinants of exercise capacity in children and adolescents with severe therapy-resistant asthma.

OBJECTIVE: To evaluate the exercise capacity of children and adolescents with severe therapy resistant asthma (STRA) aiming to identify its main determinants. METHODS: Cross-sectional study including individuals aged 6-18 years with a diagnosis of STRA. Clinical (age and gender), anthropometric (weight, height and body mass index) and disease control data were collected. Lung function (spirometry), cardiopulmonary exercise testing (CPET) and exercise-induced bronchoconstriction (EIB) test were performed. RESULTS: Twenty-four patients aged 11.5 ± 2.6 years were included. The mean forced expiratory volume in one second (FEV1) was 91.3 ± 9.2%. EIB occurred in 54.2% of patients. In CPET, the peak oxygen uptake (VO2peak) was 34.1 ± 7.8 mL kg-1 min-1. A significant correlation between ventilatory reserve and FEV1 (r = 0.57; p = 0.003) was found. Similarly, there was a significant correlation between CPET and percent of FEV1 fall in the EIB test for both VE/VO2 (r = 0.47; p = 0.02) and VE/VCO2 (r = 0.46; p = 0.02). Patients with FEV1<80% had lower ventilatory reserve (p = 0.009). In addition, resting heart rate correlated with VO2peak (r=-0.40; p = 0.04), VE/VO2 (r = 0.46; p = 0.02) and VE/VCO2 (r = 0.48; p = 0.01). CONCLUSIONS: Exercise capacity is impaired in approximately 30% of children and adolescents with STRA. The results indicate that different aspects of aerobic fitness are influenced by distinct determinants, including lung function and EIB.

Diagnostic performance of the physical activity-related question of the GINA questionnaire to detect exercise-induced bronchoconstriction in asthma.

INTRODUCTION: The aim of the study was to evaluate the diagnostic performance of the item concerning physical activity of the Global Initiative for Asthma (GINA) asthma control questionnaire for detection of exercise-induced bronchoconstriction (EIB) in children and adolescents. MATERIAL AND METHODS: We divided participants (aged 6-18 years) with a diagnosis of asthma into two groups according to the GINA severity classification: mild/moderate asthma (MMA) and severe therapy-resistant asthma (STRA). We collected anthropometric, clinical and functional data (spirometry) and performed an EIB test. We used item 4 of the GINA questionnaire regarding exercise-induced symptoms to assess the diagnostic power of this instrument. RESULTS: We included 40 patients (17 with MMA and 23 with STRA) with a mean age of 11.3 years and a mean FEV1z-score of -0.33, of who 13 (32.5%) were classified as having uncontrolled asthma. Of the patients with uncontrolled asthma, 7 (53.8%) exhibited a decrease in the FEV1 after the EIB test. We found a higher frequency of EIB in participants with FEV1 z-score values of less than -1.0 compared to those with a z-score of -1.0 or greater (P = .05). There were no significant differences in the frequency of EIB based on disease severity and control. We also found no association of item 4 (GINA) with EIB. The area under the ROC curve demonstrated that the discriminative power of the GINA questionnaire for the detection of EIB is inadequate (P = .41), with sensitivity of 42.1% and specificity of 57.1%. CONCLUSIONS: The item concerning physical activity in the GINA questionnaire has insufficient diagnostic power to detect EIB in children and adolescents with asthma.

Peripheral muscle strength is associated with aerobic fitness and use of antibiotics in patients with cystic fibrosis.

AIMS: Individuals with cystic fibrosis (CF) may develop muscle abnormalities, although little is known on its clinical and functional impact. This study aimed to evaluate the association of peripheral muscle strength with aerobic fitness, habitual physical activity, lung function and the use of antibiotics (ATB) in patients with CF. METHODS: A cross-sectional study where individuals aged ≥6 years underwent peripheral muscle strength evaluation (biceps, quadriceps and hamstrings) and performed a cardiopulmonary exercise test. Demographic, anthropometric, genetic, lung function and total days of ATB use within 1 year of tests were also collected. RESULTS: Correlation was found for biceps (r = .45; P = .002) strength with the peak oxygen consumption (VO2 peak). Muscle strength (biceps and quadriceps) also correlated with the ventilatory equivalent for oxygen consumption (VE /VO2 ) at anaerobic threshold (AT) and with the ventilatory equivalent for carbon dioxide production (VE /VCO2 ) both at AT and peak exercise. Negative correlations were found for quadriceps (r = -.39) and hamstrings (r = -.42) with the total days of ATB use in the following year. Patients needing to use ATB presented lower biceps strength (P = .05) and individuals with VO2 peak lower than 37 mL·kg-1 ·min-1 presented lower muscle strength for both biceps (P = .01) and quadriceps (P = .02). CONCLUSIONS: The results have shown that peripheral muscle strength is associated with aerobic fitness and the use of antibiotics in patients with CF.

Evaluation of the exercise intensity generated by active video gaming in patients with cystic fibrosis and healthy individuals.

BACKGROUND: Adherence of patients with cystic fibrosis (CF) to exercise is challenging. Here we compared the physiological responses during the use of interactive video games (VG) with the cardiopulmonary exercise test (CPET) in healthy and CF subjects. METHODS: Cross-sectional study including CF and healthy (CON) subjects older than 6 years. Individuals were evaluated in two visits. At visit one, anthropometric measures, spirometry and CPET were performed. In the second visit, a physical activity questionnaire was applied and gas analyses performed during the use (10 min) of both Nintendo Wii (Wii Fit Plus: (1) Obstacle Course, (2) Rhythm Boxing and (3) Free Run) and Xbox One (Just Dance 2015: (1) Love Me Again, (2) Summer and (3) Happy). RESULTS: Twenty-five CON and 30 CF patients were included. The mean FEV1 (%) was significantly lower in the CF group compared to CON. There were no differences between groups at peak exercise (CPET) for heart rate (HR), oxygen consumption (VO2) and minute ventilation (VE). In the CON group, games 2 and 3 (Xbox) and game 3 (Nintendo) increased HR to values similar to the anaerobic threshold (AT), while for the CF group this occurred for games 2 (Xbox) and 3 (Nintendo). As for VO2 and VE, both groups obtained similar responses as compared to AT values in games 2 (Xbox) and 3 (Nintendo). CONCLUSION: The use of VG generated a cardiorespiratory response similar to AT levels found during CPET, indicating that it may be an alternative for exercise training of CF individuals.

Modified Shuttle Test Distance Correlates With Peak Oxygen Uptake in Children and Adolescents With Severe Therapy-Resistant Asthma.

INTRODUCTION: Several tests may be used to assess exercise intolerance in severe therapy-resistant asthma (STRA), including the gold standard cardiopulmonary exercise test (CPET) and the modified shuttle test (MST). OBJECTIVE: To correlate the distance achieved in the MST with peak oxygen uptake (VO2peak) and to compare the maximal heart rate (HRmax) obtained in both tests in children and adolescents with STRA. METHODS: This is a cross-sectional study, with 19 children and adolescents with STRA. Demographic, anthropometric, clinical data, and spirometric values were collected. CPET and the MST were performed in two consecutive visits. HRmax, pulse oxygen saturation, and dyspnea were compared between tests. The distance achieved in the MST was correlated with VO2peak. RESULTS: Nineteen patients with a mean age of 11.5 ± 2.5 years were included. The mean HRmax (bpm) achieved was 180.8 ± 12.10 for the MST and 187.6 ± 9.35 for CPET, whereas the mean HRmax as a percentage of predicted (HRmax%) was 90.7 ± 6.5 for the MST and 93.8 ± 4.5 for CPET. A difference of only 6 bpm was found for HRmax (p = 0.10) and of 3% for HRmax% (p = 0.06) between tests. A strong correlation was found between the MST (r = 0.79; p = 0.001) and VO2peak measured through CPET. However, there were no correlations between the MST and both body mass index (r = -0.14; p = 0.564) and forced expiratory volume in the first second - FEV1 (r = -0.02; p = 0.917). CONCLUSION: The results demonstrate that the MST distance strongly correlates with VO2peak, measured through CPET, and the main physiological variable responses were similar between both tests. Our results provide additional data for the use of the MST to assess exercise capacity in children and adolescents with STRA.

MAXIMUM HEART RATE MEASURED VERSUS ESTIMATED BY DIFFERENT EQUATIONS DURING THE CARDIOPULMONARY EXERCISE TEST IN OBESE ADOLESCENTS. / FREQUÊNCIA CARDÍACA MÁXIMA MEDIDA VERSUS ESTIMADA POR DIFERENTES EQUAÇÕES DURANTE O TESTE DE EXERCÍCIO CARDIOPULMONAR EM ADOLESCENTES OBESOS.

OBJECTIVE: To compare the values of measured maximum heart rate (HRmax) and maximum heart rate estimated by different equations during the cardiopulmonary exercise test (CPET) in obese adolescents. METHODS: This is a cross-sectional study. Adolescents aged between 15 and 18 years old, with obesity (BMI Z-score>2.0) were included. Demographic and anthropometric data were collected, followed by CPET, recording HRmax. The highest heart rate reached at peak exercise was considered as HRmax. The comparison between measured and estimated HRmax values was performed using four previous equations. Descriptive statistics and the ANOVA test (Bonferroni post-test) were used. RESULTS: Fifty-nine obese adolescents were included, 44% of them male. The mean age was 16.8±1.2 years old and the BMI (Z-score) was 3.0±0.7. At peak exercise, the mean HRmax (bpm) was 190.0±9.2, the respiratory coefficient was 1.2±0.1, and the VO2max (mL/kg/min) was 26.9±4.5. When comparing the measured values of HRmax with those estimated by the different formulas, the equations "220-age", "208-0.7 x age" and "207-0.7 x age" were shown to overestimate (p<0.001) the measured HRmax results in obese adolescents. Only the "200-0.48 x age" equation presented similar results (p=0.103) with the values measured in the CPET. CONCLUSIONS: The findings of the present study demonstrate that the equation "200-0.48 x age" seems to be more adequate to estimate HRmax in obese adolescents.

OBJETIVO: Comparar os valores de frequência cardíaca máxima (FCmáx) medidos e estimados por diferentes equações durante o teste de exercício cardiopulmonar (TECP) em adolescentes obesos. MÉTODOS: Trata-se de um estudo transversal. Foram incluídos adolescentes, de idades entre 15 e 18 anos, com obesidade (escore-Z do índice de massa corpórea - IMC>2,0). Coletaram-se dados demográficos e antropométricos, seguidos da realização do TECP, pela qual foi registrada a FCmáx. O valor mais elevado de frequência cardíaca (FC) atingida no pico do exercício foi considerado como a FCmáx. A comparação entre os valores de FCmáx medidos e os estimados pelas equações foi realizada empregando-se quatro equações prévias. Utilizaram-se a estatística descritiva e o teste de ANOVA (pós-teste de Bonferroni). RESULTADOS: Foram incluídos 59 adolescentes obesos, sendo 44% do sexo masculino. A média de idade foi de 16,8±1,2 anos e a do IMC (escore-Z), de 3,0±0,7. No pico do exercício, a média de FCmáx (batimentos por minuto - bpm) foi de 190,0±9,2, o coeficiente de troca respiratória de 1,2±0,1 e o consumo máximo de oxigênio - VO2máx (mL/kg/min) - de 26,9±4,5. Ao comparar-se os valores medidos de FCmáx com os estimados pelas diferentes fórmulas, demonstrou-se que as equações "220-idade", "208-0,7 x idade" e a "207-0,7 x idade" superestimam (p<0,001) os resultados medidos de FCmáx em adolescentes obesos. Apenas a equação "200-0,48 x idade" apresentou resultados similares (p=0,103) com os valores mensurados no TECP. CONCLUSÕES: Os achados do presente estudo demonstram que a equação "200-0,48 x idade" parece ser mais adequada para estimar a FCmáx em adolescentes obesos.

Frequência cardíaca máxima medida versus estimada por diferentes equações durante o teste de exercício cardiopulmonar em adolescentes obesos / Maximum heart rate measured versus estimated by different equations during the cardiopulmonary exercise test in obese adolescents

RESUMO Objetivo: Comparar os valores de frequência cardíaca máxima (FCmáx) medidos e estimados por diferentes equações durante o teste de exercício cardiopulmonar (TECP) em adolescentes obesos. Métodos: Trata-se de um estudo transversal. Foram incluídos adolescentes, de idades entre 15 e 18 anos, com obesidade (escore-Z do índice de massa corpórea - IMC>2,0). Coletaram-se dados demográficos e antropométricos, seguidos da realização do TECP, pela qual foi registrada a FCmáx. O valor mais elevado de frequência cardíaca (FC) atingida no pico do exercício foi considerado como a FCmáx. A comparação entre os valores de FCmáx medidos e os estimados pelas equações foi realizada empregando-se quatro equações prévias. Utilizaram-se a estatística descritiva e o teste de ANOVA (pós-teste de Bonferroni). Resultados: Foram incluídos 59 adolescentes obesos, sendo 44% do sexo masculino. A média de idade foi de 16,8±1,2 anos e a do IMC (escore-Z), de 3,0±0,7. No pico do exercício, a média de FCmáx (batimentos por minuto - bpm) foi de 190,0±9,2, o coeficiente de troca respiratória de 1,2±0,1 e o consumo máximo de oxigênio - VO2máx (mL/kg/min) - de 26,9±4,5. Ao comparar-se os valores medidos de FCmáx com os estimados pelas diferentes fórmulas, demonstrou-se que as equações "220-idade", "208-0,7 x idade" e a "207-0,7 x idade" superestimam (p<0,001) os resultados medidos de FCmáx em adolescentes obesos. Apenas a equação "200-0,48 x idade" apresentou resultados similares (p=0,103) com os valores mensurados no TECP. Conclusões: Os achados do presente estudo demonstram que a equação "200-0,48 x idade" parece ser mais adequada para estimar a FCmáx em adolescentes obesos.

ABSTRACT Objective: To compare the values of measured maximum heart rate (HRmax) and maximum heart rate estimated by different equations during the cardiopulmonary exercise test (CPET) in obese adolescents. Methods: This is a cross-sectional study. Adolescents aged between 15 and 18 years old, with obesity (BMI Z-score>2.0) were included. Demographic and anthropometric data were collected, followed by CPET, recording HRmax. The highest heart rate reached at peak exercise was considered as HRmax. The comparison between measured and estimated HRmax values was performed using four previous equations. Descriptive statistics and the ANOVA test (Bonferroni post-test) were used. Results: Fifty-nine obese adolescents were included, 44% of them male. The mean age was 16.8±1.2 years old and the BMI (Z-score) was 3.0±0.7. At peak exercise, the mean HRmax (bpm) was 190.0±9.2, the respiratory coefficient was 1.2±0.1, and the VO2max (mL/kg/min) was 26.9±4.5. When comparing the measured values of HRmax with those estimated by the different formulas, the equations "220-age", "208-0.7 x age" and "207-0.7 x age" were shown to overestimate (p<0.001) the measured HRmax results in obese adolescents. Only the "200-0.48 x age" equation presented similar results (p=0.103) with the values measured in the CPET. Conclusions: The findings of the present study demonstrate that the equation "200-0.48 x age" seems to be more adequate to estimate HRmax in obese adolescents.