Wendell Arthur Lopes

Is obesity related to postexercise cardiac autonomic recovery

Dear Editor, We read with great interest the article by El Agaty, Kirmani, and Labban (2016) which evaluated the heart rate variability (HRV) during recovery from exercise in overweight healthy female young adults. According to the authors, the results provided evidence that overweight is associated with delayed vagal reactivation after exercise. We would like to add some comments and contributions to this article. Although many studies have shown an autonomic dysfunction at rest in obese subjects, little is known about the impact of obesity on postexercise cardiac autonomic recovery (Eyre, Duncan, Birch, & Fisher, 2014). The autonomic stress imposed by exercise continues during the postexercise period, with parasympathetic reactivation and sympathetic withdrawal (Peçanha et al., 2017). For this reason, HRV analysis during the postexercise period has been proposed to be a surrogate marker of the cardiac autonomic recovery (Peçanha et al., 2017). Heart rate variability is usually measured during 5min rest periods or other stationary condition to guarantee the minimum points to reliably assess of HRV (TaskForce, 1996). The stationary condition is needed in order to assume the “stationarity of the data,” a mathematical concept that must be present in the heart rate time series for the spectral analysis of HRV (Peçanha et al., 2017). However, this is impossible for the analysis of HRV after exercise (Peçanha et al., 2017). Goldberger et al. (2006) proposed an alternative for the analyzing HRV during recovery phase from exercise, since the problem with postexercise HRV analysis could be minimized by dividing the entire recovery period into short segments and analyzing HRV in each of them. These authors suggest that the rootmean square differences of successive RR intervals calculated in 30s (RMSSD30s) segments seem to represent accurately the parasympathetic reactivation after the exercise. However, this alternative is problematic for the frequency domain HRV analysis, because there is variation of parasympathetic and sympathetic modulations (Peçanha et al., 2017). Therefore, using the conventional frequency domain approach to perform spectral analysis of the postexercise recovery curve will result in inconsistent values, since this is unable to catch the timerelated variations in frequency and amplitude throughout the recovery period (Peçanha et al., 2017). Consequently, the spectral analysis of the whole recovery time in the postexercise period has been discouraged (Peçanha et al., 2017). Although this study presents an important research question, their results should be viewed with caution since the conclusions were based on the frequency domain data, which is not indicated to represent HRV postexercise recovery (Peçanha et al., 2017). Also, the RMSSD data, which has shown good reproducibility and represent the parasympathetic system (Peçanha et al., 2017), was not different between the recovery period and baseline in neither groups. Another important aspect that needs to be considered is the exercise intensity, which affects autonomic responses during the recovery period (Peçanha et al., 2017). The authors used a submaximal step test, but the intensity reached in each group was not mentioned. The high value of HR observed in the overweight group after exercise could be attributed to the high exercise intensity reached in this group. In conclusion, based on the study of El Agaty et al. (2016), it is not possible to confirm that obesity is related to delayed vagal reactivation after exercise in healthy female young adults. Further studies should apply adequate methodological approach in postexercise cardiac autonomic recovery analysis.

Comparação de três equações para predição da gordura corporal por bioimpedância em jovens obesas

INTRODUCAO: A impedância bioeletrica (BIA) tem sido bastante utilizada para o monitoramento da composicao corporal em individuos de diferentes idades e estados nutricionais. Entretanto, nao se sabe qual das equacoes propostas para criancas e adolescentes e a mais recomendada para utilizacao em adolescentes com excesso de peso. Objetivo: Verificar a concordância dos metodos de BIA usando tres equacoes diferentes com a absorciometria de raio-X de dupla energia (DXA), para analise da composicao corporal de adolescentes com sobrepeso e obesidade. METODOS: Participaram do estudo 27 adolescentes do sexo feminino, com sobrepeso e obesidade. Foram avaliados o percentual de gordura corporal (%GC), a massa gorda (MG) e a massa livre de gordura (MLG) por DXA e por BIA utilizando as equacoes propostas por Houtkooper, Schaefer e Deurenberg. ANOVA oneway, graficos de Bland-Altman e o coeficiente de correlacao intraclasse foram utilizados para comparacao e verificacao da concordância entre os metodos. RESULTADOS: A BIA utilizando a equacao proposta por Houtkooper foi a unica que nao apresentou diferenca estatistica significativa na estimativa de %GC, MG e MLG em comparacao ao DXA e apresentou boa concordância com o DXA na estimativa de %GC (-1,9 ± 3,29%), MG (1,5 ± 2,59 kg) e MLG (1,4 ± 2,60 kg), bem como boa reprodutibilidade para %GC (CCI = 0,81), MG (0,96) e MLG (0,89). As equacoes de Schaefer e de Deurenberg apresentaram menor concordância com o DXA, superestimando a MG e subestimando a MLG e apresentaram reprodutibilidade de moderada a baixa na maioria das medidas da composicao corporal. CONCLUSAO: Quando comparamos as tres equacoes propostas para BIA com o DXA, verificamos que a equacao proposta por Houtkooper foi a que melhor concordou com DXA e apresentou boa reprodutibilidade para estimar %GC, MG e MLG em adolescentes com sobrepeso e obesidade.Introduction: The bioelectrical impedance (BIA) has been widely used for monitoring body composition of individuals of different ages and nutritional statuses. However, it is unknown which of the equations for children and adolescents is the most recommended to be used for adolescents who are overweight. Objective: To assess the agreement of the BIA method using three different equations with dual energy X-ray absorptiometry (DXA) for analysis of body composition in overweight and obesity. Methods: Twenty-seven female adolescents with overweight or obesity were included in this study. The percentage of body fat (%BF), fat mass (FM) and fat-free mass (FFM) were evaluated by DXA and BIA using the equations proposed by Houtkooper, Schaefer and Deurenberg. Oneway ANOVA, Bland-Altman plots and the intraclass correlation coefficient were used for comparison and verification of the agreement among the methods. Results: BIA using the equation proposed by Houtkooper was the only one that showed no statistically significant difference in the estimating %BF, FM and FFM compared to DXA and showed good agreement with DXA in estimating %BF (-1.9±3.29), FM (1.5±2.59) and FFM (1.4±2.60) and good reproducibility for %BF (0.81), FM (0.96) and FFM (0.89). The Schaefer and Deurenberg equations showed less agreement with DXA, overestimating the MG and underestimating the FFM, and presented moderate to low reproducibility in most measures of body composition. Conclusion: When we compared the three equations proposed to BIA with DXA, we find that the Houtkooper equation was the best agreed with DXA and showed good reproducibility for estimate %BF, FM and FFM in female adolescents with overweight and obesity.

Comparison of three equations for predicting the body fat by bioimpedance in young obese females

INTRODUCAO: A impedância bioeletrica (BIA) tem sido bastante utilizada para o monitoramento da composicao corporal em individuos de diferentes idades e estados nutricionais. Entretanto, nao se sabe qual das equacoes propostas para criancas e adolescentes e a mais recomendada para utilizacao em adolescentes com excesso de peso. Objetivo: Verificar a concordância dos metodos de BIA usando tres equacoes diferentes com a absorciometria de raio-X de dupla energia (DXA), para analise da composicao corporal de adolescentes com sobrepeso e obesidade. METODOS: Participaram do estudo 27 adolescentes do sexo feminino, com sobrepeso e obesidade. Foram avaliados o percentual de gordura corporal (%GC), a massa gorda (MG) e a massa livre de gordura (MLG) por DXA e por BIA utilizando as equacoes propostas por Houtkooper, Schaefer e Deurenberg. ANOVA oneway, graficos de Bland-Altman e o coeficiente de correlacao intraclasse foram utilizados para comparacao e verificacao da concordância entre os metodos. RESULTADOS: A BIA utilizando a equacao proposta por Houtkooper foi a unica que nao apresentou diferenca estatistica significativa na estimativa de %GC, MG e MLG em comparacao ao DXA e apresentou boa concordância com o DXA na estimativa de %GC (-1,9 ± 3,29%), MG (1,5 ± 2,59 kg) e MLG (1,4 ± 2,60 kg), bem como boa reprodutibilidade para %GC (CCI = 0,81), MG (0,96) e MLG (0,89). As equacoes de Schaefer e de Deurenberg apresentaram menor concordância com o DXA, superestimando a MG e subestimando a MLG e apresentaram reprodutibilidade de moderada a baixa na maioria das medidas da composicao corporal. CONCLUSAO: Quando comparamos as tres equacoes propostas para BIA com o DXA, verificamos que a equacao proposta por Houtkooper foi a que melhor concordou com DXA e apresentou boa reprodutibilidade para estimar %GC, MG e MLG em adolescentes com sobrepeso e obesidade.Introduction: The bioelectrical impedance (BIA) has been widely used for monitoring body composition of individuals of different ages and nutritional statuses. However, it is unknown which of the equations for children and adolescents is the most recommended to be used for adolescents who are overweight. Objective: To assess the agreement of the BIA method using three different equations with dual energy X-ray absorptiometry (DXA) for analysis of body composition in overweight and obesity. Methods: Twenty-seven female adolescents with overweight or obesity were included in this study. The percentage of body fat (%BF), fat mass (FM) and fat-free mass (FFM) were evaluated by DXA and BIA using the equations proposed by Houtkooper, Schaefer and Deurenberg. Oneway ANOVA, Bland-Altman plots and the intraclass correlation coefficient were used for comparison and verification of the agreement among the methods. Results: BIA using the equation proposed by Houtkooper was the only one that showed no statistically significant difference in the estimating %BF, FM and FFM compared to DXA and showed good agreement with DXA in estimating %BF (-1.9±3.29), FM (1.5±2.59) and FFM (1.4±2.60) and good reproducibility for %BF (0.81), FM (0.96) and FFM (0.89). The Schaefer and Deurenberg equations showed less agreement with DXA, overestimating the MG and underestimating the FFM, and presented moderate to low reproducibility in most measures of body composition. Conclusion: When we compared the three equations proposed to BIA with DXA, we find that the Houtkooper equation was the best agreed with DXA and showed good reproducibility for estimate %BF, FM and FFM in female adolescents with overweight and obesity.

Prevalence of metabolically healthy obese phenotype and associated factors in South American overweight adolescents: a cross-sectional study

OBJECTIVE The aim of this study was to verify the prevalence of metabolically healthy obese (MHO) phenotype and associated factors in South American adolescents who are overweight. METHODS A cross-sectional study was carried out with 340 overweight adolescent boys and girls between 10 and 18 y of age. The participants were classified as MHO according to two definitions: absence of any metabolic syndrome component and absence of insulin resistance (IR). The MHO phenotype-associated factors analyzed were age, sex, nutritional status, waist circumference (WC), body composition, metabolic profile, and cardiorespiratory fitness. Multivariable logistic regression was used to determine predictors of MHO using odds ratios with 95% confidence intervals. RESULTS The prevalence of MHO in South American overweight adolescents was 49.4% and 55.9% according to MS and IR criteria, respectively. Sex and WC were predictors of the MHO phenotype, considering MS classification criterion. For the IR criterion, age, WC, and triacylglycerol levels were independent predictors of MHO in adolescents. Cardiorespiratory fitness did not predict MHO phenotype in any of the criteria used. CONCLUSIONS The prevalence of MHO in South American overweight adolescents was high and varied according to the definition used. Age, sex, WC, and triacylglycerolslevel were independent predictors of the MHO phenotype in this population.

Does resistance training modulate cardiac autonomic control in diseased but not in healthy individuals

We read with great interest the recent meta-analysis written by Bhati et al. [1], which investigated the effect of resistance training (RT) on the modulation of cardiac autonomic control. The authors concluded that RT has no or only a minimal effect on the cardiac autonomic control of healthy individuals, but leads to improvement in the cardiac autonomic control of diseased individuals. We appreciate the authors’ thorough analysis. However, some limitations of the findings of their review should be noted. Although the selection of databases, the search strategies applied, and the analysis of the quality of the studies are adequate and consistent with the guidelines for conducting systematic reviews and meta-analyses [2], the decision to include uncontrolled studies and data obtained using different experimental designs appears to have compromised the implementation of the meta-analysis as well as the interpretation of the data. Regarding the effects of RT on the cardiac autonomic control of healthy individuals, the authors conclude that there does not seem to be a significant change in cardiac autonomic control after RT. However, in the analyses of subgroups with different heart rate variability (HRV) domains, although no significant differences were identified between the control condition and RT, there was high heterogeneity in, for example, the mean N–N interval (NN), low-frequency (LF)/high-frequency (HF), and the standard deviation of the instantaneous beat-to-beat variability (SD1). Thus, the conclusions need to be drawn in light of the presence of this heterogeneity, which may be related to the demographics of the study participants, who were mostly middle-aged and older men [3]. On the other hand, the conclusions drawn about the effects of RT on diseased individuals are, in our view, more worrisome and deserve further clarification. The authors conclude that RT seems to be effective at improving cardiac autonomic control in diseased individuals. Although significant differences were observed in the subgroup analyses, with RT favored in all HRV domains, heterogeneity was present in almost all comparisons. In addition, the number of studies included in the meta-analysis of subgroups of individuals with diseases was much lower than that included in the analysis of healthy individuals, which is important to take into account when drawing conclusions based on the results. Moreover, in the nonlinear domain, only two studies by the same author were used, which could explain the significant effect of the variable SD1 and the low heterogeneity present in this analysis. It also does not seem prudent to consider different diseases in the analysis, since that some diseases are clearly associated with alterations in cardiac autonomic control (e.g., hypertension) while others do not (e.g., obesity) [4]. Thus, the analyses need to be conducted according to the particular diseases considered if we are to discern the true effects of RT on cardiac autonomic control in diseased individuals. Although the authors have commented on Kingsley’s elegant systematic review [5], which examined the acute and chronic effects of RT on cardiac autonomic control, Bhati et al.’s findings add little to Kingsley’s findings, since they only reinforce the conclusion that cardiac autonomic control does not change after RT in healthy individuals and (despite the limitations of the analyses discussed above) suggest that RT can induce favorable changes in diseased individuals. In conclusion, Bhati et al. [1] analyzed an important issue: the effect of RT on the modulation of cardiac autonomic control. However, the results of their meta-analysis should be interpreted with caution due to the limitations * Wendell Arthur Lopes warthurlopes@gmail.com

Trp64Arg polymorphism of the ADRB3 gene associated with maximal fat oxidation and LDL‐C levels in non‐obese adolescents

OBJECTIVE To analyze the association between the Trp64Arg polymorphism of the ADRB3 gene, maximal fat oxidation rates and the lipid profile levels in non-obese adolescents. METHODS 72 schoolchildren, of both genders, aged between 11 and 17 years, participated in the study. The anthropometric and body composition variables, in addition to total cholesterol, HDL-c, LDL-c, triglycerides, insulin, and basal glycemia, were evaluated. The sample was divided into two groups according to the presence or absence of the polymorphism: non-carriers of the Arg64 allele, i.e., homozygous (Trp64Trp: n=54), and carriers of the Arg64 allele (Trp64Arg+Arg64Arg: n=18), in which the frequency of the Arg64 allele was 15.2%. The maximal oxygen uptake and peak of oxygen uptake during exercise were obtained through the symptom-limited, submaximal treadmill test. Maximal fat oxidation was determined according to the ventilatory ratio proposed in Lusks table. RESULTS Adolescents carrying the less frequent allele (Trp64Arg and Arg64Arg) had higher LDL-c levels (p=0.031) and lower maximal fat oxidation rates (p=0.038) when compared with non-carriers (Trp64Trp). CONCLUSIONS Although the physiological processes related to lipolysis and lipid metabolism are complex, the presence of the Arg 64 allele was associated with lower rates of FATMAX during aerobic exercise, as well as with higher levels of LDL-c in adolescents.

Influence of polymorphisms of the beta-2 adrenergic receptor on the presence of exercise-induced bronchospasm in adolescents

Abstract Objective: To determine the influence of polymorphisms of the beta-2 adrenergic receptor (ADRB2) in triggering exercise-induced bronchospasm (EIB) in adolescents. Methods: The subjects were divided into two groups: present EIB (EIB+) (n=45) and absent EIB (EIB−) (n=115). The bronchial provocation test with exercise was performed with a protocol that consisted of walking/running for at least eight minutes at high intensity, i.e., >85% of maximum heart rate, considering EIB+ as a 10% decrease in forced expiratory volume in one second (FEV1). The genotyping of the ADRB2 gene was performed by the Taqman method, using the Step One Plus system. Independent t-test, Mann–Whitney and Chi-square tests, as well as Spearmans correlation coefficient were used for the statistical analysis. Results: Age, body weight, height, FEV1, FVC and FEV1/FVC ratio were lower in the EIB+ group when compared to EIB− (p<0.05). There were no significant differences in the proportion of the allele at position 27 and Arg16Gly and Gln27Glu genotypes between the EIB+ and EIB− groups (p=0.26; p=0.97 and p=0.43, respectively). However, there was a trend toward statistical significance regarding the greater proportion of the Gly16 allele for the EIB+ when compared to the EIB− group (p=0.08). Conclusions: The presence of polymorphisms associated with the Glu27 allele and Arg16Gly and Gln27Glu genotypes had no influence on EIB. However, the statistical trend toward greater frequency of the Gly16 allele in individuals with EIB+ can be considered evidence of the influence of polymorphisms of the ADBR2 gene on EIB in adolescents.

Comparación de tres ecuaciones para predicción de la grasa corporal por bioimpedancia en jóvenes obesas

INTRODUCAO: A impedância bioeletrica (BIA) tem sido bastante utilizada para o monitoramento da composicao corporal em individuos de diferentes idades e estados nutricionais. Entretanto, nao se sabe qual das equacoes propostas para criancas e adolescentes e a mais recomendada para utilizacao em adolescentes com excesso de peso. Objetivo: Verificar a concordância dos metodos de BIA usando tres equacoes diferentes com a absorciometria de raio-X de dupla energia (DXA), para analise da composicao corporal de adolescentes com sobrepeso e obesidade. METODOS: Participaram do estudo 27 adolescentes do sexo feminino, com sobrepeso e obesidade. Foram avaliados o percentual de gordura corporal (%GC), a massa gorda (MG) e a massa livre de gordura (MLG) por DXA e por BIA utilizando as equacoes propostas por Houtkooper, Schaefer e Deurenberg. ANOVA oneway, graficos de Bland-Altman e o coeficiente de correlacao intraclasse foram utilizados para comparacao e verificacao da concordância entre os metodos. RESULTADOS: A BIA utilizando a equacao proposta por Houtkooper foi a unica que nao apresentou diferenca estatistica significativa na estimativa de %GC, MG e MLG em comparacao ao DXA e apresentou boa concordância com o DXA na estimativa de %GC (-1,9 ± 3,29%), MG (1,5 ± 2,59 kg) e MLG (1,4 ± 2,60 kg), bem como boa reprodutibilidade para %GC (CCI = 0,81), MG (0,96) e MLG (0,89). As equacoes de Schaefer e de Deurenberg apresentaram menor concordância com o DXA, superestimando a MG e subestimando a MLG e apresentaram reprodutibilidade de moderada a baixa na maioria das medidas da composicao corporal. CONCLUSAO: Quando comparamos as tres equacoes propostas para BIA com o DXA, verificamos que a equacao proposta por Houtkooper foi a que melhor concordou com DXA e apresentou boa reprodutibilidade para estimar %GC, MG e MLG em adolescentes com sobrepeso e obesidade.Introduction: The bioelectrical impedance (BIA) has been widely used for monitoring body composition of individuals of different ages and nutritional statuses. However, it is unknown which of the equations for children and adolescents is the most recommended to be used for adolescents who are overweight. Objective: To assess the agreement of the BIA method using three different equations with dual energy X-ray absorptiometry (DXA) for analysis of body composition in overweight and obesity. Methods: Twenty-seven female adolescents with overweight or obesity were included in this study. The percentage of body fat (%BF), fat mass (FM) and fat-free mass (FFM) were evaluated by DXA and BIA using the equations proposed by Houtkooper, Schaefer and Deurenberg. Oneway ANOVA, Bland-Altman plots and the intraclass correlation coefficient were used for comparison and verification of the agreement among the methods. Results: BIA using the equation proposed by Houtkooper was the only one that showed no statistically significant difference in the estimating %BF, FM and FFM compared to DXA and showed good agreement with DXA in estimating %BF (-1.9±3.29), FM (1.5±2.59) and FFM (1.4±2.60) and good reproducibility for %BF (0.81), FM (0.96) and FFM (0.89). The Schaefer and Deurenberg equations showed less agreement with DXA, overestimating the MG and underestimating the FFM, and presented moderate to low reproducibility in most measures of body composition. Conclusion: When we compared the three equations proposed to BIA with DXA, we find that the Houtkooper equation was the best agreed with DXA and showed good reproducibility for estimate %BF, FM and FFM in female adolescents with overweight and obesity.