Chaotic analysis of heart rate dynamics after an exercise with flexible pole / Análise caótica da dinâmica da frequência cardíaca após exercício com barra flexível

INTRODUCTION: Exercises with a flexible pole have been applied in clinical practice for upper limb rehabilitation. Nevertheless, its acute effects on cardiac autonomic regulation are unclear. OBJECTIVE: To evaluate the acute effects of exercise with flexible pole on complex behavior of heart rate variability (HRV). METHOD: We investigated 32 healthy female volunteers aged between 18 and 25 years who performed a session of exercise with a flexible pole. HRV was analyzed 10 minutes before and 10 minutes immediately after the exercise. RESULTS: Exercises with a flexible pole did not significantly change time and frequency domain indices of HRV. Non-linear analysis of HRV through the Higuchi Fractal Dimension was not significantly changed during recovery from exercise compared to the control reading at rest. CONCLUSION: Exercises with the flexible pole were unable to acutely change chaotic behavior of heart rate dynamics. This is advantageous for assessments of levels of rehabilitative treatment required in such patients; and their susceptibility to dynamical diseases.

INTRODUÇÃO: Exercícios com uma barra flexível têm sido usados na prática clínica para a reabilitação do membro superior. No entanto, os seus efeitos agudos sobre a regulação autonômica cardíaca não estão bem esclarecidas. OBJETIVO: Avaliar os efeitos agudos do exercício com barra flexível sobre o comportamento complexo da variabilidade da frequência cardíaca (VFC). MÉTODO: Foram investigadas 32 voluntárias saudáveis com idades entre 18 e 25 anos que realizaram uma sessão de exercício com barra flexível. A VFC foi analisada 10 minutos antes e 10 minutos imediatamente depois do exercício. RESULTADOS: Os exercícios com a barra flexível não alteraram significativamente os domínios de tempo e frequência de VFC. Análise não-linear da VFC através da Dimensão Fractal Higuchi mostra que a mesma não foi significativamente alterada durante a recuperação do exercício em relação ao controle pré-exercício. CONCLUSÃO: O exercício com a barra flexível não alterou profundamente o comportamento caótico da dinâmica da frequência cardíaca. Isto é vantajoso para a avaliação de níveis de tratamento de reabilitação necessário em tais pacientes; e sua suscetibilidade a doenças dinâmicas.

A single bout of exercise with a flexible pole induces significant cardiac autonomic responses in healthy men

OBJECTIVES: Flexible poles can provide rapid eccentric and concentric muscle contractions. Muscle vibration is associated with a "tonic vibration reflex” that is stimulated by a sequence of rapid muscle stretching, activation of the muscle spindles and stimulation of a response that is similar to the myotatic reflex. Literature studies analyzing the acute cardiovascular responses to different exercises performed with this instrument are lacking. We investigated the acute effects of exercise with flexible poles on the heart period in healthy men. METHOD: The study was performed on ten young adult males between 18 and 25 years old. We evaluated the heart rate variability in the time and frequency domains. The subjects remained at rest for 10 min. After the rest period, the volunteers performed the exercises with the flexible poles. Immediately after the exercise protocol, the volunteers remained seated at rest for 30 min and their heart rate variability was analyzed. RESULTS: The pNN50 was reduced at 5-10 and 15-20 min after exercise compared to 25-30 min after exercise (p = 0.0019), the SDNN was increased at 25-30 min after exercise compared to at rest and 0-10 min after exercise (p = 0.0073) and the RMSSD was increased at 25-30 min after exercise compared to 5-15 min after exercise (p = 0.0043). The LF in absolute units was increased at 25-30 min after exercise compared to 5-20 min after exercise (p = 0.0184). CONCLUSION: A single bout of exercise with a flexible pole reduced the heart rate variability and parasympathetic recovery was observed approximately 30 min after exercise. .

Análise da concordância entre instrumentos de avaliação do equilíbrio corporal em idosos / Analysis of agreement of assessment tools of body balance in the elderly

CONTEXTUALIZAÇÃO: Diagnosticar os parâmetros clínicos associados com as quedas em idosos tornou-se um grande desafio para a comunidade científica. Apesar da existência de diversos instrumentos direcionados à avaliação do equilíbrio corporal em idosos, ainda é escasso o número de trabalhos que investigaram e discutiram a concordância entre os diversos métodos. OBJETIVO: Analisar a correlação entre alguns testes usados para avaliar o equilíbrio corporal no idoso. MÉTODOS: Tratou-se de um estudo transversal, observacional, realizado com 30 voluntárias idosas comunitárias, hígidas, com diferentes níveis de condicionamento físico. Foram utilizados o Teste de Alcance Funcional Anterior (TAF), a Escala de Equilíbrio de Berg (EEB), o teste Timed Up and Go (TUG) e o Teste de Equilíbrio de Tinetti (Performance Oriented Mobility Assessment - POMA). A correlação dos dados foi realizada por meio da aplicação do Coeficiente de Correlação de Spearman, com nível de significância de 5 por cento (p<0,05). RESULTADOS: Observou-se correlação positiva e moderada entre o TAF e a EEB (r=0,4845; p=0,0067), entre o TAF e a POMA (r=0,4136; p= 0,0231), entre a EEB e a POMA (r=0,6088; p=0,0004). CONCLUSÃO: Os testes são complementares, dado que se mostraram com particularidades e limitações distintas. Torna-se razoável, portanto, a aplicação conjunta desses instrumentos para melhor avaliar o equilíbrio de idosas.

BACKGROUND: The diagnosis of clinical parameters associated with falls in the elderly has become a major challenge for the scientific community. Despite the existence of several tools aiming to assess body balance in the elderly, it is still scarce the number of studies that have investigated and discussed the agreement between different methods. OBJECTIVE: To analyze the correlation between tests used to assess the body balance in the elderly. METHODS: This was a cross-sectional, observational study conducted with 30 healthy female community-dwelling elderly volunteers with different levels of physical conditioning. The Functional Reach Test (FRT), the Berg Balance Scale (BBS), the Timed Up and Go (TUG) and the Performance-Oriented Mobility Assessment of Balance (POMA) were used. The data analysis was performed by using the Spearmam's rank correlation coefficient, with a significance level of 5 percent (p<0.05). RESULTS: There was positive and moderate correlation between the FRT and BBS (r=0.4845, p=0.0067), between FRT and POMA (r=0.4136, p=0.0231), and between BBS and POMA (r=0.6088, p=0.0004). CONCLUSION: The tests are complementary since they showed specific and distinct limitations. It is reasonable, therefore, to use these instruments together to get better assessment of elderly body balance.

Exercise training attenuates acute hyperalgesia in streptozotocin-induced diabetic female rats

OBJECTIVES: We investigated the effects of chronic (eight weeks) low-to moderate-intensity swimming training on thermal pain sensitivity in streptozotocin-induced diabetic female rats. METHODS: Female Wistar rats (n = 51) were divided into the following groups: trained streptozotocin-induced diabetic rats [hyperglycemic trained (HT)], sedentary streptozotocin-induced diabetic rats [hyperglycemic sedentary (HS)], normoglycemic trained rats (NT) and normoglycemic sedentary rats (NS). Diabetes was induced by a single injection of streptozotocin (50 mg/kg, i.p.). One day after the last exercise protocol (60 min/day, five days/week for eight weeks) in the trained groups or after water stress exposure (ten min/twice a week) in the sedentary groups, the rats were subjected to a hot plate test. RESULTS: After eight weeks of swimming training, streptozotocin-induced diabetic rats presented a significantly lower body mass (trained: 219.5±29 g, sedentary: 217.8±23 g) compared with the normoglycemic groups (trained: 271±24 g, sedentary: 275.7±32 g). Interestingly, we did not find differences in blood glucose levels (mg/dl) between the trained and sedentary groups of the hyperglycemic or normoglycemic rats (HT: 360.2±6.6, HS: 391.7±6.7, NT: 83.8±14.0, NS: 77.5±10.1). In the hot plate test, the rats from the HT group presented a significantly lower latency than the other rats (HT: 11.7±7.38 s, HS: 7.02±7.38 s, NT: 21.21±7.64 s, NS: 22.82±7.82 s). CONCLUSION: Low-to-moderate swimming training for a long duration reduces thermal hyperalgesia during a hot plate test in streptozotocin-induced diabetic female rats.