Efeito do treinamento de força excêntrica no controle autonômico da freqüência cardíaca de idosos durante o repouso e contrações isométricas

The purpose of the present study was to investigate the effect of eccentric strength training (ST) on autonomic control of heart rate (HR) evaluated at rest and during isometric exercise. Nine healthy men (62 ±2 years old) were submitted to 12 weeks of ST for knee extensors and flexors muscles (2x/week, 2-4 series of 8-12 repetitions, 70-80% of eccentric peak torque). Before and after the ST, the HR and its variability were evaluated at rest (supine and seated conditions) and during the sub-maximal isometric contractions (SIC; 15, 30 and 40% of maximal voluntary contraction) of knee extension wich were performed during 240s or until exhaustion. The HR was obtained at pre- (60s), during and post SIC (120s). Then, the variation (&#8710;) between the resting HR and HR at 10, 30, 60s and end of contraction observed during each SIC was analyzed. The HR variability was evaluated by the RMSSD index, which was determined in resting condition and during SIC (i.e., two windows of 30s in duration at the beginning and end of R-R interval data). The ANOVA two-way (repeated measures) and t-test was utilized for statistical analysis (p < 0.05). The ST increased the eccentric torque (extension: 210 ± 38 to 252.7 ± 61 N.m, flexion: 117.6 ± 25.1 to 133 ± 27.3 N.m) , but did not change the HR and HR variability at rest (HR supine: 62 ± 11 to 65 ± 9 bpm, HR seated: 62 ± 11 to 66 ± 9, RMSSD supine: 28.5 ± 18 to 21.5 ± 8.4, RMSSD seated: 30.4 ± 2 to 18.9 ± 6.2). The ST did not modify the isometric peak torque (177.6 ± 25 to 195.2 ± 31,2 N.m) and the time of execution of each SIC (15%: 240 to 240s, 30%: 203.4 ± 55 to 218 ± 5s, 40%: 135.6 ± 56.7 to 144.6 ± 55.6s). During the SIC, the pattern of HR response (significative increase in &#8710;HR from 30s to the end of contraction in 15 and 40%) and the RMSSD index (significative decrease from the first 30s to the last 30s of contraction in all levels of effort) was similar for the pre- and post training. Despite the ST increased the eccentric torque, it did not generate changes in the autonomic control of heart rate at rest and during the SIC.Universidade Federal de Minas GeraisThe aging process is marked by several physiological changes, and the reduction in muscle strength is very important one. In order to minimize this force decline there are recommendations for using resistance training for elderly persons. Some studies available in the literature state that the eccentric contraction would be more suitable for the elderly, since it generates less cardiovascular overload during the exercise. However, the chronic effect of the eccentric strength training (EST) on the heart rate (HR) autonomic modulation is unclear. So, the aim of the first study was to investigate whether the EST changes HR and heart rate variability (HRV) during submaximal isometric contractions (SIC). This study included 17 volunteers who form divided into two groups: training group (9 men, 62 ± 2 years) and control group (8 men, 64 ± 4 years). The results indicate that although this type of training improves eccentric strength, the EST does not have any effect sufficient to promote changes in the autonomic control of HR during isometric exercise. Another important factor to consider is the increase in incidence of cardiovascular disease that occurs with aging. Furthermore, there are modifications of autonomic control of HR related to ageing that are detected by the reduction in HRV and changes in the complexity of physiological dynamics. Based on these considerations the aim of the second study was to verify whether changes in HR modulation, caused by the aging process, can be detected by the Shannon entropy (SE), conditional entropy (CE) and symbolic analysis (SA). In this study were evaluated 21 elderly (63 ± 3 years) and 21 young (23 ± 2 years). Elderly present distributions of patterns in HRV that are similar to young subjects. However, the patterns are more repetitive, thus reducing the complexity. This decrease of complexity comes from the increased presence of stable patterns and a decreased presence of highly variable patterns. This difference indicates that apparently healthy older subjects have a marked unbalance in autonomic regulation. The results of the second study indicate that non-linear approaches might be helpful to better characterize the changes on the autonomic control of HR in the aging process

Modulação autonômica da frequência cardíaca e treino de força excêntrica no processo de envelhecimento

The aging process is marked by several physiological changes, and the reduction in muscle strength is very important one. In order to minimize this force decline there are recommendations for using resistance training for elderly persons. Some studies available in the literature state that the eccentric contraction would be more suitable for the elderly, since it generates less cardiovascular overload during the exercise. However, the chronic effect of the eccentric strength training (EST) on the heart rate (HR) autonomic modulation is unclear. So, the aim of the first study was to investigate whether the EST changes HR and heart rate variability (HRV) during submaximal isometric contractions (SIC). This study included 17 volunteers who form divided into two groups: training group (9 men, 62 ± 2 years) and control group (8 men, 64 ± 4 years). The results indicate that although this type of training improves eccentric strength, the EST does not have any effect sufficient to promote changes in the autonomic control of HR during isometric exercise. Another important factor to consider is the increase in incidence of cardiovascular disease that occurs with aging. Furthermore, there are modifications of autonomic control of HR related to ageing that are detected by the reduction in HRV and changes in the complexity of physiological dynamics. Based on these considerations the aim of the second study was to verify whether changes in HR modulation, caused by the aging process, can be detected by the Shannon entropy (SE), conditional entropy (CE) and symbolic analysis (SA). In this study were evaluated 21 elderly (63 ± 3 years) and 21 young (23 ± 2 years). Elderly present distributions of patterns in HRV that are similar to young subjects. However, the patterns are more repetitive, thus reducing the complexity. This decrease of complexity comes from the increased presence of stable patterns and a decreased presence of highly variable patterns. This difference indicates that apparently healthy older subjects have a marked unbalance in autonomic regulation. The results of the second study indicate that non-linear approaches might be helpful to better characterize the changes on the autonomic control of HR in the aging process.Universidade Federal de Minas GeraisO processo de envelhecimento é marcado por várias transformações fisiológicas, dentre estas se observa uma redução da força muscular. Existem recomendações para o uso do treinamento contra resistência para a população idosa com intuito de amenizar este declínio. Ainda, estudos na literatura referem que a contração do tipo excêntrica seria a mais adequada para indivíduos idosos, uma vez que gera menor sobrecarga cardiovascular no momento da realização da contração. No entanto, não está claro o efeito crônico de um treinamento de força excêntrica (TFE) sobre a modulação autonômica da frequência cardíaca (FC). Assim o primeiro estudo teve como objetivo investigar se o TFE modifica a FC e variabilidade da frequência cardíaca (VFC) durante contrações voluntárias isométricas submáximas (CVIS). Participaram deste estudo 17 voluntários que foram alocados em dois grupos: grupo treinamento (9 homens, 62 ± 2 anos) e grupo controle (8 homens, 64 ± 4 anos). Os resultados obtidos indicam que apesar deste tipo de treinamento melhorar a força excêntrica, este não causou adaptações suficientes para promover alterações no controle autonômico da FC durante exercício isométrico. Outro fator importante a ser considerado é o aumento da incidência da doença cardiovascular com o envelhecimento. Somado a isso, tem sido observado que com o avanço da idade o controle autonômico da FC também sofre modificações constatadas por uma redução da VFC e mudanças na complexidade das dinâmicas fisiológicas. Diante destas considerações foi conduzido o segundo estudo que teve por objetivo verificar se as alterações na modulação da FC, causada pelo processo do envelhecimento, podem ser detectadas pela entropia de Shanon (ES), entropia condicional (EC) e análise simbólica (AS). Foram avaliados 23 idosos (63±3 anos) e 21 jovens (23±2 anos). Observou-se que com o processo de envelhecimento as distribuições de padrões presentes na VFC permanecem similares aos indivíduos jovens. No entanto, os padrões são mais repetitivos, reduzindo assim a complexidade. Esta redução é o resultado do aumento da presença de padrões estáveis e da diminuição de padrões altamente variáveis. Estas diferenças indicam que indivíduos idosos aparentemente saudáveis, apresentam um desequilíbrio na regulação autonômica cardíaca. Os resultados do segundo estudo indicam que as análises empregadas podem ser úteis para melhor caracterizar as alterações no controle autonômico da FC, decorrentes do avanço da idade

Perception of barriers to physical exercise in women population over 60

Abstract Aims This study evaluated the possible barriers to the permanence of physical exercise (PE) of old women. Methods The study population comprised 61 old women participants for at least one year of a supervised PE program, who underwent anamnesis, and applied the Barriers Questionnaire to Physical Activity Practice in the Elderly (QBPAFI). Exploratory factorial analysis was used to evaluate QBPAFI data. The analysis of principal component was applied to the 22 questions through orthogonal rotation to analyze the correlation between the questions. The Kaiser-Meyer-Olkin test was applied to evaluate the suitability of the sample size, and the Bartlett's test to assess whether the original matrix correlation is an identity matrix. Eigenvalues greater than 1 were considered for analysis. Results The motivational factor was the major determinant of perceived barriers (43.3%), followed by psychosocial (12.29%), facilities and appearance (8.75%), and exercise conditions (8.10%) factors. Conclusion Knowing the benefits of physical activity, and the main barriers that prevent the permanence of active old people to physical exercise programs, new strategies must be taken to increase the rate of adherence of this group

Respiração lenta e profunda aumenta a modulação vagal em gestantes

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.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 cardiofrequencímetro, 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

Perfil de idosos admitidos em serviço de fisioterapia frente à sazonalidade = Profile of elderly admitted to a physical therapy center as a function of seasonality

OBJETIVOS: Analisar o perfil e a prevalência de doenças em idosos admitidos em duas estações do ano distintas, em um serviço público de fisioterapia de um município de médio porte localizado em zona de clima subtropical de altitude. MÉTODOS: Um estudo transversal analisou prontuários de pacientes encaminhados nos meses que compreenderam o verão e o inverno de 2011. Foram incluídos os prontuários de idosos (acima de 60 anos de idade) de ambos os sexos e excluídos os prontuários sem informações sobre o diagnóstico médico atual. Foram coletadas as variáveis idade e sexo e os diagnósticos atuais e pregressos. Para análise comparativa quanto ao perfil dos idosos admitidos nos dois períodos do ano, utilizou-se o teste Qui-quadrado. RESULTADOS: Foram analisados dados de 71 idosos. A média de idade foi de 69,2±8,1 anos e 48 (70,4%) eram do sexo feminino. Os diagnósticos mais frequentes no momento do encaminhamento foram de doenças traumato-ortopédicas (60,6%). O maior número de admissões ocorreu durante o inverno (62,0%). Os diagnósticos no momento do encaminhamento foram, respectivamente no verão e no inverno: traumatoortopédicos 17 (63,0%) e 26 (59,1%); reumatológicos 3 (11,1%) e 10 (22,7%); neurológicos 5 (18,5%) e 4 (9,1%); pós-operatório 2 (7,4%) e 4 (9,1%) (p=0,64). CONCLUSÕES: No inverno ocorreu maior demanda de encaminhamentos de idosos ao serviço de fisioterapia em comparação ao verão, com predomínio de mulheres em ambas as estações do ano. As causas de encaminhamento mais prevalentes foram relacionadas à traumatoortopedia, mas não houve diferença significativa na frequência dos diagnósticos conforme a estação do ano. O conhecimento sobre o perfil dos idosos admitidos em serviços de fisioterapia é importante para o planejamento de ações voltadas a essa faixa etária, com a realização de campanhas de informação, prevenção e promoção da saúd

Impact of a dual task intervention on physical performance of older adults who practice physical exercise

Physical exercises, especially multicomponent training, can improve cognitive functions and physical impairments in older adults. The aim this study was to purpose of this two-arm clinical trial was to investigate the effects of the addition of a dual task to multicomponent training on physical performances of community-dwelling older adults who practice physical exercise. Seventy-one older adults were divided into a control group (CG) and intervention group (IG). Participants of the CG performed isolated multicomponent training, participants of the IG performed multicomponent training associated with cognitive tasks and both protocols lasted 12 weeks. The assessment consisted of flexibility, handgrip strength, lower limb strength, balance, functional mobility and aerobic capacity. The CG presented greater flexibility than the IG, regardless of time. There was a worse performance in lower limb strength, regardless of group. The addition of a dual task to the multicomponent training was not able to improve physical performances of older adults. Further studies are needed to confirm whether the dual task training contributes to both cognitive and physical benefits in older adults who practice physical exercise