Acute whole-body electromyostimulation associated with dynamic exercises did not alter cardiac autonomic modulation and oxygen uptake in obese and eutrophic men

Abstract Aim: To contrast the acute effects of whole-body electromyostimulation (WB-EMS) with sham associated with dynamic exercises on cardiovascular, ventilatory, metabolic, and autonomic responses in men with obesity and controls. Methods: A randomized cross-over and double-blind trial with nine eutrophic (23.6 years; 23 ± 1.4 kg/m2) and ten men with obesity (26 ± 4 years; 38 ± 7 kg/m2), who were randomized to receive WB-EMS-Sham or Sham-WB-EMS with 30 min of rest between protocols. WB-EMS protocol (Miha Bodytec®) was applied at the motor level, frequency = 85 Hz, pulse duration = 350 μs, cycle on = 6′; cycle off = 4′. Sham group performed the same exercises with the electric current turned off. Throughout both protocols, subjects executed two dynamic exercises of 5 minutes each (step-up and step down associated with shoulder flexion, and lunge exercise associated with elbow flexion) in the same order. R-R intervals and breath-by-breath respiratory gases analysis were collected during the protocols. Heart rate variability (HRV) indexes were obtained using linear and nonlinear analysis. The level of statistical significance was set at p < 0.05. Results: Regarding both exercises, participants with obesity presented reduced oxygen uptake, higher ventilation, respiratory rate, blood pressure, and Borg scores (p < 0.05) when contrasted with controls, as expected. However, no significant differences were found for HRV indexes between groups (p > 0.05). In addition, WB-EMS did not increase oxygen uptake or altered autonomic modulation when contrasted with sham in both groups (p < 0.05). Conclusion: Obesity has a negative impact on symptoms and functional capacity. However, WB-EMS did not acutely enhance oxygen uptake or HRV during exercise in a population with obesity.

Responses of different functional tests in candidates for bariatric surgery and the association with body composition, metabolic and lipid profile.

Individuals with obesity can have metabolic disorders and may develop impairments that affect the ability to exercise. The maximal incremental cardiopulmonary exercise test is widely used to assess functional capacity. However, submaximal tests such as the two-minute step test (2MST) and the six-minute walk test (6MWT) also allow this assessment. We propose to analyze whether body composition, metabolic and lipid profile influence the maximal and submaximal performance, and investigate these variables in response to different functional tests. Forty-four individuals with obesity, aged 18-50 years, underwent analysis of body composition, metabolic and lipid profile, incremental treadmill test (ITMT), 6MWT, and 2MST. One-way ANOVA, Pearson or Spearman correlation, and Stepwise multiple linear regression analysis were performed. ITMT induced a greater metabolic, ventilatory, cardiovascular, and perceived exertion demand when compared to the 6MWT and 2MST (p < 0.05). In addition, 2MST elicited a higher chronotropic (HR) and metabolic (V̇O2) demand when compared to the 6MWT (p < 0.05). Significant correlations were found between tests and body composition, metabolic and lipid profile. Fat mass and low-density lipoprotein can explain 30% of the V̇O2 variance in the ITMT; and fat mass, glucose, and performance in the 2MST can explain 42% of the variance of the distance walked in the ITMT. Obesity and its metabolic impairments are capable of influencing responses to exercise. ITMT generated greater demand due to the high stress imposed, however, 2MST demanded greater metabolic and chronotropic demand when compared to the 6MWT.

Effects of Whole-Body Electromyostimulation Associated with Dynamic Exercise on Functional Capacity and Heart Rate Variability After Bariatric Surgery: a Randomized, Double-Blind, and Sham-Controlled Trial.

PURPOSE: Bariatric surgery is the most effective treatment for morbid obesity. In association with dietary restrictions, the ability to exercise in the immediate post-surgical phase is limited. In this context, whole-body electromyostimulation (WB-EMS), strategy that stimulates various muscle groups, in conjunction with physical exercise, holds promise for improving functional capacity, and cardiac autonomic control, following surgery. The purpose of this study was to analyze whether a rehabilitation program consisting of WB-EMS with 30 exercise training sessions following bariatric surgery significantly improves functional capacity, body mass and heart rate variability (HRV). METHODS: Randomized, double-blind, and sham-controlled trial. Twenty obesity patients were randomized into the WB-EMS (n = 10) and sham (n = 10) groups. On average, 7 days after surgery, individuals underwent a six-minute walk test (6MWT), HRV, and body composition analysis at rest. The next day, patients initiated an exercise training protocol, five times per week, over 6 weeks. Walking distance changes (post-pre = ΔWD) obtained by 6MWT and HRV indices were determined following the intervention. RESULTS: Only WB-EMSG significantly increased WD and body mass index (BMI) after the intervention (p = 0.002) and ΔWD was significantly higher in this group when compared with sham (p = 0.04). Moreover, both groups demonstrated an improvement in key measures of HRV after the intervention. CONCLUSION: An exercise training intervention initiated shortly after bariatric surgery improved functional capacity and cardiac autonomic tone. Improvements in functional capacity and BMI following exercise training were greater with the addition of WB-EMS but did not promote additional improvements in HRV beyond that realized with exercise training alone.

Effects of two nonpharmacological treatments on the sleep quality of women with nocturia: a randomized controlled clinical trial.

INTRODUCTION AND HYPOTHESIS: The objective was to check the effects of two nonpharmacological treatments on the sleep quality of women with nocturia. METHODS: A randomized controlled clinical trial in which 40 women with nocturia were randomized into two groups; one was subjected to tibial nerve stimulation (GTNS) and the other received pelvic floor muscle training associated with behavioral therapy (GPFMT). Both groups were followed for 12 weeks, with one session/week; evaluated by the Pittsburgh Sleep Quality Index (PSQI), King's Heath Questionnaire (KHQ), and Epworth Sleepiness Scale (ESS). The Wilcoxon test was used to compare intra-group data and the Mann-Whitney test for intergroup results. Effect size and confidence interval were calculated, and the level of significance was set at 5%. RESULTS: Both groups showed improvements in quality of sleep, observed by the PSQI total score (GTNS from 9 ± 0.88 to 7 ± 0.94, p = 0.002; GPFMT from 8 ± 0.80 to 5 ± 0.94, p < 0.001) and the sleep/energy domain of the KHQ (GTNS from 66.66 ± 9.03 to 16.66 ± 7.20, p = 0.002; GPFMT from 66.66 ± 9.30 to 0.00 ± 7.26, p = 0.001). CONCLUSIONS: Both nonpharmacological treatments proposed (TNS or PFMT) were equally able to improve quality of sleep of women with nocturia.

COPD assessment test and FEV1: do they predict oxygen uptake in COPD?

BACKGROUND: Chronic obstructive pulmonary disease (COPD) manifests itself in complex ways, with local and systemic effects; because of this, a multifactorial approach is needed for disease evaluation, in order to understand its severity and impact on each individual. Thus, our objective was to study the correlation between easily accessible variables, usually available in clinical practice, and maximum aerobic capacity, and to determine models for peak oxygen uptake (VO2peak) estimation in COPD patients. SUBJECTS AND METHODS: Individuals with COPD were selected for the study. At the first visit, clinical evaluation was performed. During the second visit, the volunteers were subjected to the cardiopulmonary exercise test. To determine the correlation coefficient of VO2peak with forced expiratory volume in 1 second (FEV1) (% pred.) and the COPD Assessment Test score (CATs), Pearson or Spearman tests were performed. VO2 at the peak of the exercise was estimated from the clinical variables by simple and multiple linear regression analyses. RESULTS: A total of 249 subjects were selected, 27 of whom were included after screening (gender: 21M/5F; age: 65.0±7.3 years; body mass index: 26.6±5.0 kg/m2; FEV1 (% pred.): 56.4±15.7, CAT: 12.4±7.4). Mean VO2 peak was 12.8±3.0 mL⋅kg-1⋅min-1 and VO2peak (% pred.) was 62.1%±14.9%. VO2peak presented a strong positive correlation with FEV1 (% pred.), r: 0.70, and a moderate negative correlation with the CATs, r: -0.54. In the VO2peak estimation model based on the CAT (estimated VO2peak =15.148- [0.185× CATs]), the index explained 20% of the variance, with estimated error of 2.826 mL⋅kg-1⋅min-1. In the VO2peak estimation model based on FEV1 (estimated VO2peak =6.490+ [0.113× FEV1]), the variable explained 50% of the variance, with an estimated error of 2.231 mL⋅kg-1⋅min-1. In the VO2peak estimation model based on CATs and FEV1 (estimated VO2peak =8.441- [0.0999× CAT] + [0.1000× FEV1]), the variables explained 55% of the variance, with an estimated error of 2.156 mL⋅kg-1⋅min-1. CONCLUSION: COPD patients' maximum aerobic capacity has a significant correlation with easily accessible and widely used clinical variables, such as the CATs and FEV1, which can be used to estimate peak VO2.

Respiração lenta e profunda aumenta a modulação vagal em gestantes / Deep and slow breathing increases vagal modulation in pregnant women

OBJETIVOS: Comparar a resposta da modulação autonômica da frequência cardíaca de gestantes e mulheres não gestantes, antes e após a manobra de acentuação da arritmia sinusal respiratória. MÉTODOS: Foi realizado um estudo transversal com amostra de 24 mulheres, divididas em dois grupos: grupo gestantes (independente da idade gestacional) e grupo controle (não gestantes). A avaliação consistiu em registro dos intervalos RR por um cardio frequencímetro, para análise de índices lineares e não lineares da variabilidade da frequência cardíaca. As avaliações foram feitas no repouso em decúbito lateral esquerdo, antes e após a manobra de acentuação da arritmia sinusal respiratória, que consiste em respirações lentas de cinco a seis ciclos por minuto. A razão expiração/inspiração e a diferença entre a inspiração e a expiração foram avaliadas durante a manobra. Foram comparados os resultados obtidos entre os dois grupos (gestantes e não gestantes), assim como os obtidos em cada grupo, antes e após a manobra. Para a análise estatística o nível de significância considerado foi p<0,05. RESULTADOS: Os índices lineares mostraram valores iniciais da modulação simpática (banda de baixa frequência) aumentados nas gestantes quando comparadas às mulheres não gestantes (gestantes: 68,9±28,1; controles: 49,3±11,7; p=0,002). Após a manobra respiratória, o índice obtido pela raiz quadrada da média do quadrado das diferenças entre os intervalos RR normais adjacentes aumentou no grupo gestantes (pré- manobra: 34,5±5,7; pós-manobra: 38,9±5,8; p=0,027), indicando aumento da atuação parassimpática para essa população após a aplicação da manobra. Além disso, houve aumento dos valores de complexidade, sugeridos pela entropia de Shanon após a manobra, para ambos os grupos, sendo o aumento maior nas gestantes. Em relação aos índices avaliados durante a manobra, ambos os grupos apresentaram valores da razão expiração/inspiração maiores que 1, o que sugere integridade do sistema nervoso autônomo. CONCLUSÕES: Houve melhora da regulação do sistema nervoso autônomo ao final da manobra respiratória para as gestantes, sugerindo que o padrão de respiração lenta e profunda possa aumentar a modulação vagal e conferir efeito cardioprotetor, além de ocasionar relaxamento e sensação de bem-estar.

AIMS: To compare the responses of the heart rate autonomic modulation in pregnant and non-pregnant women before and after the respiratory sinus arrhythmia maneuver. METHODS: A cross-sectional study was conducted with a sample of 24 women, divided into two groups: pregnant group (independent of gestational age) and control group (non-pregnant). The evaluation consisted of recording the RR intervals using a cardiofrequencimeter, for analysis of linear and nonlinear indices of heart rate variability. The evaluations were made at rest in left lateral decubitus, before and after the maneuver of accentuation of respiratory sinus arrhythmia, consisting of slow breaths five to six cycles per minute. The expiration/inspiration ratio and the difference between inspiration and expiration were evaluated during the maneuver. Results were compared between the two groups (pregnant and non-pregnant), as well as those obtained in each group before and after the maneuver. For the statistical analysis the level of significance considered was p<0.05. RESULTS: Linear indices showed increased baseline sympathetic modulation (low frequency band) in pregnant women when compared to non-pregnant women (pregnant women: 68.9±28.1; non pregnant women: 49.3±11.7; p=0,002). After the respiratory maneuver, the root mean square of successive differences in the RR intervals index increased in the pregnant group (pre-maneuver: 34.5±5.7; post-maneuver: 38.9±5.8; p=0,002) indicating an increase in the parasympathetic system for this population after the maneuver. In addition, there was an increase in the complexity values after the maneuver, suggested by the Shanon entropy for both groups, being the increase higher in the pregnant women. Regarding the indices evaluated during the respiratory sinus arrhythmia maneuver, both groups presented expiration/inspiration ratio values greater than 1, which suggests integrity of the autonomic nervous system. CONCLUSIONS: There was an improvement in the regulation of the autonomic nervous system after the respiratory maneuver for pregnant women, suggesting that the slow and deep breathing pattern may increase vagal modulation and confer a cardioprotective effect, besides causing relaxation and a sense of well-being.

Increased sympathetic modulation and decreased response of the heart rate variability in controlled asthma.

OBJECTIVE: To compare the autonomic modulation of heart rate (HR) in asthmatic and healthy volunteers to correlate it with the forced expiratory volume in the first second (FEV1). METHODS: Ten healthy and 14 asthmatic volunteers were included in this cross-sectional study. The volunteers underwent a cardiopulmonary exercise test, spirometry and a register of both resting heart rate variability (HRV) in the supine and seated positions along with HRV during the respiratory sinus arrhythmia maneuver (M-RSA). RESULTS: At rest in supine, asthmatic volunteers presented a higher HR (77.1 ± 9.9 vs. 68.7 ± 8.7 bpm), shorter interval between two R waves (R-Ri) (807.5 ± 107.2 vs. 887.5 ± 112.7 ms) when compared with the healthy volunteers, respectively. Moreover, in the frequency domain of HRV, there was increased low frequency (LF) index (50.4 ± 17.1 vs. 29.2 ± 11.1 n.u.) and decreased high frequency (HF) index (49.4 ± 17.1 vs. 70.7 ± 11.1 n.u.). During the M-RSA, the asthmatic presented higher HR (82.6 ± 10.0 vs. 72.4 ± 7.6 bpm) and lower values of R-Ri (746.4 ± 92.1 vs. 846.4 ± 81.4 ms) and approximate entropy (ApEn) (0.7 ± 0.0 vs. 0.8 ± 0.1). FEV1 was strongly correlated with the change of the continuous beat-to-beat variability of HR (SD2) index from the seated to the supine position (r = 0.78). CONCLUSION: Controlled asthma in adults appears to induce an increased sympathetic modulation and attenuated response to the postural changes and the M-RSA. Furthermore, there is a correlation between the airways' obstruction and HRV, especially during postural changes.

The incremental shuttle walk test in older Brazilian adults.

BACKGROUND: Despite widespread use of the incremental shuttle walk distance (ISWD), there are no reference equations for predicting it. OBJECTIVES: We aimed to evaluate ISWD in healthy subjects and to establish a reference equation for its prediction. METHODS: 131 Brazilian individuals (61 males; 59 ± 10 years) performed 2 walk tests in a 10-m long corridor. We assessed height, weight, body mass index, forced expiratory volume in 1 s, forced vital capacity and self-reported physical activity. RESULTS: Mean ISWD was greater in males than in females (606 ± 167 vs. 443 ± 117 m; p < 0.001). ISWD correlated significantly (p < 0.05) with age (r = -0.51), height (r = 0.54) and weight (r = 0.20). A predictive model including age, height, weight and gender explained 50.3% of the ISWD variance. In an additional group of 20 subjects prospectively studied, the difference between measured and predicted ISWD was not statistically significant (534 ± 84 vs. 552 ± 87 m, respectively), representing 97 ± 12% of the predicted value calculated with our reference equation for ISWD. CONCLUSIONS: This reference equation including demographic and anthropomorphic attributes could be useful for interpreting the walking performance of patients with chronic diseases that affect exercise capacity.

Walking for the assessment of balance in healthy subjects older than 40 years.

BACKGROUND: The Berg scale and the timed 'up and go' test (TUG) are established measures to assess mobility in frail older adults. As an alternative to self-paced tests to assess aerobic exercise capacity, the incremental shuttle walk test (ISWT) was developed. We hypothesized that ISWT may be useful for the assessment of aerobic capacity and balance simultaneously in healthy adults. OBJECTIVES: There are 3 objectives: (1) to evaluate the intra-tester reliability of TUG in healthy subjects; (2) to compare the validity of TUG, ISWT and comfortable gait speed (GS) to evaluate balance assessed by the Berg balance scale, and (3) to evaluate the correlations among these walking tests. METHODS: We studied a sample of 64 subjects (82.81% women) aged 40-84 years to assess the intra-tester reliability of TUG. Of these, 21 subjects also performed ISWT, GS and the Berg balance scale. We also assessed height, weight, body mass index, spirometry and reported physical activity. RESULTS: The average time to complete TUG was 7.23+/-1.27 s. The interclass correlation coefficient of TUG was excellent (0.936; 95% CI: 0.895-0.961). Age (r=0.36), GS (r=-0.64), GS/height (r=-0.44), ISWT (r=-0.65) and the Berg score (r=-0.65) were correlated with TUG (p<0.05). The Berg score was significantly (p<0.05) correlated with GS (r=0.61) and ISWT (r=0.61). Moreover, ISWT was mutually related with GS (r=0.68). We evaluated 2 models of linear regression, using GS and TUG as independent variables in each of them. In the 1st model, GS described 47% of the ISWT variability. In the 2nd, TUG described 42.7% of the ISWT variability. CONCLUSIONS: The capacity of walking is related to balance in healthy adults and seniors. Our results suggest the usefulness of ISWT as a new tool for the simultaneous evaluation of the aerobic capacity and balance in healthy subjects. An important part of the ISWT variation was explained by GS and TUG. Secondly, we confirmed the significant influence of age in the TUG performance and the excellent reliability of this field walking test.