Efeitos sub-agudos do exercício com oclusão vascular na função endotelial de homens jovens

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Educação Física, 2015.Objetivo: Verificar os efeitos agudos e sub-agudos do exercício de preensão manual, combinado ou não com a restrição do fluxo sanguíneo (BFR), na função endotelial de homens jovens. Métodos: Nove participantes (28 ± 2 anos) completaram uma sessão de exercício de preensão manual bilateral, com duração de 20 minutos e intensidade de 60% da contração voluntária máxima. Para induzir a BFR um manguito foi posicionado 2 cm abaixo da fossa antecubital no braço experimental (EXP) e insuflado a 80 mmHg durante o exercício. O braço EXP e o braço controle (CON) foram selecionados aleatoriamente para todos os sujeitos. A dilatação fluxo-mediada da artéria braquial (FMD) e a velocidade de fluxo sanguíneo foram mensurados por meio de ultrassonografia com Doppler em três momentos distintos: repouso, 15 e 60 minutos após o término do protocolo. Adicionalmente a velocidade de fluxo sanguíneo foi analisada durante a realização do exercício. Resultados: Foi observado um aumento significativo na FMD 15 minutos após o exercício para o braço CON (64,09 ± 16,59%, P ≤ 0,01), já no braço EXP não foram verificadas alterações (-12,48 ± 12,64, P = 0,25); foi encontrada uma diferença significativa entre os dois braços neste momento (P ≤ 0,01). A FMD retornou a valores próximos dos iniciais 60 minutos após o exercício, sem diferença entre os braços (P = 0,42). Durante a realização do exercício o braço EXP apresentou valores significativamente maiores de taxa de cisalhamento retrógrada (P ≤ 0,01) e menor taxa de cisalhamento média (P = 0,02). Conclusão: Uma única sessão de exercício de preensão manual provocou uma melhora na função endotelial 15 minutos após o término do exercício, a adição de um manguito insuflado a 80 mmHg no braço EXP aboliu esta resposta aguda.Purpose: The purpose of this study was to examine the acute and sub-acute effects of handgrip exercise combined with BFR on endothelial function on healthy young men. Methods: Nine participants (28 ± 1.8 yr) completed a single 20 min bout of bilateral handgrip exercise with 60% of their maximum voluntary contraction. To induce BFR a cuff was placed 2 cm below the antecubital fossa in the experimental arm (EXP) and inflated to 80 mmHg during the exercise bout. The EXP and control arms (CON) were randomly selected for all subjects. Brachial artery flow-mediated dilation (FMD) and blood flow velocity profiles were assessed using Doppler ultrasonography before initiation of the exercise, 15 and 60 minutes after. Blood flow velocity profiles were also assessed during the exercise. Results: There was a significant increase in FMD 15 minutes after exercise for the CON arm (64.09 ± 16.59%, P ≤ 0.01), meanwhile there was no change in the EXP arm (-12.48 ± 12.64, P = 0.25), a significant difference was observed between both arms at this time-point (P ≤ 0.01). FMD returned to near baseline values at 60 minutes after exercise, with no significant difference between arms (P = 0.42). BFR during exercise in the EXP arm resulted in a significantly higher retrograde shear rate (P ≤ 0.01) and a lower mean shear rate (P = 0.02). Conclusion: A single handgrip exercise bout provoked an acute increase on endothelial function 15 min after the exercise cessation, the addition of an inflated pneumatic cuff to the exercising arm abolished this acute response

Força, qualidade muscular e marcadores de risco cardiometabólico em mulheres idosas

O processo de envelhecimento está associado a um declínio nas funções fisiológicas, refletindo em reduções na qualidade muscular, bem como em alterações de marcadores de risco cardiometabólico. Nesse sentido, o objetivo do estudo foi verificar a associação entre qualidade muscular e marcadores de risco cardiometabólico em mulheres idosas. Trinta mulheres idosas (66,13±5,26 anos, 67,33±12,45 kg, 1,54±0,07 m, 28,20±4,72 IMC) foram submetidas à avaliação da espessura e força musculares do quadríceps, e à análise sanguínea de marcadores de risco cardiometabólico (glicemia, insulina basal, proteína C-reativa, colesterol total, HDL-colesterol, LDL-colesterol, VLDL-colesterol, triglicerídeos, e índice HOMA-IR). Não foram encontradas correlações significativas entre os fenótipos musculares e os marcadores de risco cardiometabólico estudados, mesmo com controle para fatores de confusão. A presente pesquisa indica não haver correlação entre força e qualidade muscular com os marcadores de risco cardiometabólico estudados.The aging process is associated with a decline in physiological functions, including a reduction in muscle quality, as well as changes in cardiometabolic risk factors. Thus, the aim of this study was to verify if a correlation exists between muscle strength and quality and cardiometabolic risk markers in older women. Thirty older women (66.13±5.26 years, 67.33±12.45 kg, 1.54±0.07 m, body mass index: 28.20±4.72) were submitted to the evaluation of muscle thickness and strength and blood analysis of cardiometabolic risk markers (glucose, basal insulin, C-reactive protein, total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol, triglycerides, and HOMA-IR). No significant correlations were found between muscle phenotypes and markers of cardiometabolic risk, even after adjustment for confounding factors. The present study indicates that muscle strength or quality is not correlated with markers of cardiometabolic risk

Effects of disturbed blood flow during exercise on endothelial function : a time course analysis

This study aimed to examine the time course of endothelial function after a single handgrip exercise session combined with blood flow restriction in healthy young men. Nine participants (28±5.8 years) completed a single session of bilateral dynamic handgrip exercise (20 min with 60% of the maximum voluntary contraction). To induce blood flow restriction, a cuff was placed 2 cm below the antecubital fossa in the experimental arm. This cuff was inflated to 80 mmHg before initiation of exercise and maintained through the duration of the protocol. The experimental arm and control arm were randomly selected for all subjects. Brachial artery flow-mediated dilation (FMD) and blood flow velocity profiles were assessed using Doppler ultrasonography before initiation of the exercise, and at 15 and 60 min after its cessation. Blood flow velocity profiles were also assessed during exercise. There was a significant increase in FMD 15 min after exercise in the control arm compared with before exercise (64.09%±16.59%, P=0.001), but there was no change in the experimental arm (-12.48%±12.64%, P=0.252). FMD values at 15 min post-exercise were significantly higher for the control arm in comparison to the experimental arm (P=0.004). FMD returned to near baseline values at 60 min after exercise, with no significant difference between arms (P=0.424). A single handgrip exercise bout provoked an acute increase in FMD 15 min after exercise, returning to near baseline values at 60 min. This response was blunted by the addition of an inflated pneumatic cuff to the exercising arm