Multicomponent exercise training in cardiovascular complexity in prefrail older adults: a randomized blinded clinical pilot study

The aim of this study was to investigate the effects of multicomponent training on baroreflex sensitivity (BRS) and heart rate (HR) complexity of prefrail older adults. Twenty-one prefrail community-dwelling older adults were randomized and divided into multicomponent training intervention group (MulTI) and control group (CG). MulTI performed multicomponent exercise training over 16 weeks and CG was oriented to follow their own daily activities. The RR interval (RRi) and blood pressure (BP) series were recorded for 15 min in supine and 15 min in orthostatic positions, and calculation of BRS (phase, coherence, and gain) and HR complexity (sample entropy) were performed. A linear mixed model was applied for group, assessments, and their interaction effects in supine position. The same test was used to assess the active postural maneuver and it was applied separately to each group considering assessments (baseline and post-intervention) and positions (supine and orthostatic). The significance level established was 5%. Cardiovascular control was impaired in prefrail older adults in supine position. Significant interactions were not observed between groups or assessments in terms of cardiovascular parameters. A 16-week multicomponent exercise training did not improve HR complexity or BRS in supine rest or in active postural maneuver in prefrail older adults.

Baroreflex sensitivity in frailty syndrome

Frailty is related to a decrease in the physiological reserves, which causes difficulties in maintaining homeostasis. An example of physiological mechanisms for cardiovascular homeostasis is the baroreflex. The aim of this study was to compare baroreflex among frail, prefrail, and nonfrail individuals, in supine and orthostatic positions. Community-dwelling older adults were evaluated and categorized into frail, prefrail, or nonfrail groups, according to frailty phenotype. The RR interval (RRi) and systolic blood pressure (SBP) series were recorded for 15 min in the supine and 15 min in the orthostatic positions. Mean and variance of RRi and SBP, and baroreflex evaluated by phase, gain (α), and coherence (K2) were determined. A two-way repeated measures ANOVA, with Tukey's post hoc, was applied for group, position, and their interaction effects. The significance level established was 5%. Prefrail and frail participants did not present a significant decrease in mean values of RRi after postural challenge (893.43 to 834.20 ms and 925.99 to 857.98 ms, respectively). Frail participants showed a reduction in RRi variance in supine to orthostatic (852.04 to 232.37 ms2). Prefrail and frail participants showed a decrease in K2 after postural change (0.69 to 0.52 and 0.54 to 0.34, respectively). Frail participants exhibited lower values of K2 (0.34) compared to nonfrail and prefrail participants (0.61 and 0.52, respectively). Baroreflex indicated the presence of decoupling between heart period and SBP in frail and prefrail. Thus, reduced K2 might be a marker of the frailty process.

Spectral and symbolic analysis of the effect of gender and postural change on cardiac autonomic modulation in healthy elderly subjects

The objective of this study was to use linear and non-linear methods to investigate cardiac autonomic modulation in healthy elderly men and women in response to a postural change from the supine to the standing position. Fourteen men (66.1 ± 3.5 years) and 10 women (65.3 ± 3.3 years) were evaluated. Beat-to-beat heart rate was recorded in the supine and standing positions. Heart rate variability was studied by spectral analysis, including both low (LFnu-cardiac sympathetic modulation (CSM) indicator) and high (HFnu-cardiac vagal modulation (CVM) indicator) frequencies in normalized units as well as the low frequency/high frequency (LF/HF) ratio. Symbolic analysis was performed using the following indexes: 0V percent (CSM indicator), 1V percent (CSM and CVM indicators), 2LV percent (predominantly CVM indicator) and 2ULV percent (CVM indicator). Shannon entropy was also calculated. Men presented higher LFnu and LF/HF ratio and lower HFnu and 1V percent symbolic index (57.56, 4.14, 40.53, 45.96, respectively) than women (24.60, 0.45, 72.47, 52.69, respectively) in the supine position. Shannon entropy was higher among men (3.53) than among women (3.33) in the standing position, and also increased according to postural change in men (3.25; 3.53). During postural change, the LFnu (24.60; 49.85) and LF/HF ratio (0.45; 1.72) increased, with a concomitant decrease in HFnu (72.47; 47.56) and 2LV percent (14.10; 6.95) in women. Women presented increased CSM in response to postural change and had higher CVM and lower CSM than men in the supine position. In conclusion, women in the age range studied presented a more appropriate response to a postural change than men, suggesting that cardiac autonomic modulation may be better preserved in women than in men.

Analise da resposta da frequencia cardiaca durante a realizacao de exercicio isocinetico excentrico de grupamento extensor de joelho / Analysis of heart rate response during eccentric isokinetic exercise of knee extensor muscle group

Investigar a magnitude da resposta da frequencia cardiaca durante o exercicio isocinetico excentrico do grupamento extensor do joelho, em diferentes velocidades angulares. Materiais e metodos: dez voluntarios jovens, sadios e ativos foram submetidos a contracao excentrica maxima do grupo extensor do joelho dominante. Foi utilizado um dinamometro isocinetico, nas velocidades de 30o/s, 60o/s e 120o/s, ordenadas aleatoriamente. A FC foi obtida batimento a batimento, na derivacao eletrocardiografica MC5 modificada, durante 60s pre-exercicio, durante o tempo de contracao, sendo cinco repeticoes para cada velocidade, e por 120s apos o esforco. Foram calculadas: FC media dos 60s pre-exercicio, FC pico atingida ao final do esforco, e variacao da FC (AFC), alem dos valores do pico de torque. Tambem foram comparados valores da FC media dos 6 minutos pre exercicio com os 6 minutos de recupercao. Os resultados foram comparados pelo teste de Friedman com post hoc de Dunn. O nivel de significancia estabelecido foi de 5 por cento. Resultados:nao foram observadas diferencas estatisticamente significantes entre os valores medianos da FC de repouso (68bpm para 30o/s e 60o/s, 70 bpm para 120o/s), FC pico (107bpm para 30o/s, 103 em 60o/s e 100bpm em 120o/s) e AFC (37bpm para 30o/s, 35bpm em 60o/s e 27bpm para 120o/s). A mediana dos valores de FC anteriores ao esforco foi semelhante aos de recuperacao (67bpm). Conclusao: a magnitude de resposta da FC foi semelhante, durante atividade muscular excentrica, indicando uma mesma sobrecarga cardiaca, independente da velocidade angular realizada

Avaliação do controle autonomico da frequencia cardiaca e determinação do limiar de anaerobiose em homens saudaveis e coronariopatias / Evaluation of autonomic heart rate control and determination of anaerobic threshold among healthy and coronary heart-disead men

Avaliar a frequencia cardiaca (FC) e sua variabilidade (VFC) em repouso e durante teste de exercicio fisico dinamico descontinuo tipo degrau (TEFDD-d) em homens saudaveis sedentarios (SS) e infartados ativos (IA); determinar e comparar o limiar de anaerobiose (LA) dos grupos estudados. Metodologia: forma estudados 10 SS (52,5 anos)e 6 IA (59,2 anos) em repouso nas posicoes supino e sentado e em TEFDD-d realizado em cicloergometro, iniciando na potencia com decrescimo de 5 W e acrescimo de 5 W. A Fc (bpm) e os intervalos R-R (iR-R) em ms foram captados batimento a batimento em repouso e em TEFDD-d. Foram calculados os indices RMSSD dos iR_r e a FC media das condicoes de repouso e do trecho estavel de cada nivel de potencia. O LA foi determinado aplicando o modelo semiparametrico aos dados de Fc. Os testes estatisticos utilizados forma Wilcoxon, Mann Whitney e Friedmann, nivel de significancia p < 0,05. Resultados: Em repouso os valores de RMSSD dos iR-R e da FC nao atingiram diferencas estatisticas significativas entre os grupos, ja os SS apresentaram diferencas significativas nos valores de Fc durante a mudanca postural. No nivel potencia do LA ambos os grupos nao apresentaram reducoes significativas da VFC em comparacao com 25 W. Conclusao: nossos resultados sugerem que a atividade fisica regular realizada pelos IA contribuiu para manter a capacidade aerobica como modulacao autonomica da FC similares a dos SS

Avaliação da variabilidade da frequencia cardíaca em repouso de homens saudáveis sedentários e de hipertensos e coronariopatias em treinamento físico / Resting heart rate variability in sedentary healthy men and in in trained men with hipertension and coronary heart disease

O objetivo deste estudo foi avaliar e comparar a variabilidade da frequencia cardiaca(VFC) em repouso supino e sentado de 10 homens de meia idade saudaveis (SA), 9 hipertensos (HA) e 9 com infarto do miocardio (IM), com idade media de 52, 62 e 56 anos, respectivamente. Os voluntarios SA nao praticavam atividade fisica frequentemente e os voluntarios HA e IM participavam de um programa de treinamento fisico aerobico (TFA) ha aproximadamente 3 anos. A frequencia cardiaca (FC) e os intervalos R-R(iR-R - ms) foram coletdos durante 900 s nas posicoes supina e sentada, e os voluntarios foram orientados a manter-se em repouso. Para a analise dos dados de dominio do tempo (DT), foi utilizado o indice RMSSD dos iR-R (ms). Para o dominio da frequencia (DF), foi aplicado um modelo auto-regressivo e obtidas as bandas de frequencia muito baixa (MBF), baixa (BF) e alta (AF), sendo os componentes BF e AF expressos em unidades normalizadas e na razao BF/AF. Foram utilizados os testes estatisticos nao-parametricos de Wilcoxon, de kruskall-Wallis e pos-hoc de Dunn. O nivel de significancia foi de a=5(por cento). Nao foram observadas diferencas estatisticamente significativas nos indices de VFC, avaliados no DT e no DF nas condicoes supino e sentado, nas comparacoes inter e intragrupo. Os resultados que a ausencia de diferencas entre os grupos estudados pode estar relacionada aos efeitos do do TFA realizadopelos HA e IM, comparativamente aos SA