ABSTRACT
PURPOSE: The aim of this study was to investigate the hemodynamic, oxidative stress (OS), and nitric oxide (NO) responses to a submaximal isometric exercise session (IES) involving large muscle mass. METHODS: Fourteen hypertensive (HTG: age = 35.9 ± 8.1 yr, height = 1.73 ± 0.10 m, total body mass = 78.0 ± 15.8 kg) and 10 normotensive (NTG: age = 41.1 ± 9.4 yr, height = 1.71 ± 0.12 m, total body mass = 82.3 ± 22.4 kg) participants performed two experimental sessions in the leg press and bench press: (i) control session and (ii) 8 sets × 1 min contraction at 30% maximal voluntary isometric contraction with 2-min rest interval. Blood pressure (BP) was measured at rest and during 60 min postexercise. Blood samples were collected at rest, immediately after the session, and 60 min postexercise. NO was obtained through the Griess reaction method. OS parameters were analyzed using commercial kits. A repeated-measures ANOVA with Bonferroni post hoc test was used to analyze all dependent variables. RESULTS: A significant decrease in systolic BP was observed only for HTG at 45 and 60 min postexercise (baseline vs 45 min: P = 0.03, Δ% = 4.44%; vs 60 min: P = 0.018, Δ% = 5.58%). NO increased immediately postexercise only for HTG (P = 0.008, Δ% = 16.44%). Regarding OS parameters, thiobarbituric acid reactive substances presented a significant reduction 60 min after the IES for NTG and HTG; catalase increased in both groups. CONCLUSIONS: The data showed that only 8 min of IES with a large muscle mass elicits an elevated pro-oxidant activity leading to a greater NO bioavailability, increases antioxidant reaction, and consequently reduces BP in hypertensive patients.
Subject(s)
Blood Pressure/physiology , Exercise/physiology , Hypertension/physiopathology , Muscle, Skeletal/physiology , Adult , Cross-Over Studies , Female , Hemodynamics , Humans , Hypertension/metabolism , Isometric Contraction , Lower Extremity/physiology , Male , Nitric Oxide/metabolism , Oxidation-Reduction , Oxidative Stress , Resistance Training/methods , Upper Extremity/physiologyABSTRACT
O treinamento de força (TF) é uma estratégia que diminui a pressão arterial (PA) em pacientes com hipertensão arterial (HA) estágio 1 e atenua a progressão da PA em ratos hipertensos (estágio 3). A influência do TF na remodelação cardíaca na HA não controlada ainda não está estabelecida. Objetivo: O objetivo deste estudo foi avaliar os efeitos a longo prazo do TF em intensidade moderada na remodelação cardíaca em ratos espontaneamente hipertensos (SHRs) sem tratamento. Métodos: Dez SHRs machos com HA estágio 3 (PA sistólica ≥ 180 mmHg) e cinco ratos Wistar-Kyoto (WKY) normotensos (PA sistólica < 120 mmHg) foram divididos em três grupos: sedentários normotensos (SED-WKY), sedentários hipertensos (SED-SHR) e hipertensos TF (TF-SHR). O TF foi realizado em uma escada vertical (3 dias / semana por 12 semanas, em dias não consecutivos) com 70% da carga máxima. A PA e a frequência cardíaca foram registradas. Ao final do protocolo, os animais foram sacrificados e tiveram o ventrículo esquerdo seccionado para análise histológica (hematoxilina e eosina e picrosirius red). Resultados: O TF não atenuou o ganho de peso absoluto e relativo do coração e do ventrículo esquerdo no grupo TF-SHR em comparação ao grupo SED-SHR. Não houve nenhuma diferença no volume nuclear nos cardiomiócitos e conteúdo de colágeno entre os grupos. No entanto, o TF diminuiu o número de núcleos nos cardiomiócitos e atenuou o aumento da PA sistólica no grupo TF-SHR em relação ao grupo SED-SHR. O Δ do duplo produto foi menor no grupo TF-SHR em comparação aos grupos SED-WKY e SED-SHR. Conclusões: Os dados obtidos demonstram que o TF não atenuou a hipertrofia cardíaca, mas reduziu a proliferação nuclear nos cardiomiócitos e a progressão da PA em SHR com HA severa.
Resistance training (RT) is a strategy that decreases blood pressure (BP) in patients with stage 1 hypertension and attenuates BP progression in hypertensive rats (stage 3). The influence of RT in cardiac remodeling in uncontrolled hypertension is not yet established. Objective: The aim of this study was to evaluate the long-term effects of RT in moderate intensity in cardiac remodeling in spontaneously hypertensive rats (SHRs) without treatment. Methods: Ten male SHRs with stage 3 hypertension (systolic BP ≥ 180 mmHg) and five normotensive Wistar-Kyoto (WKY) rats (systolic BP < 120 mmHg) were divided into three groups: sedentary normotensive (SED-WKY), sedentary hypertensive (SED-SHR), and RT hypertensive (RT-SHR). The RT was conducted in a vertical ladder (3 days/week for 12 weeks, on nonconsecutive days) at 70% of the maximum load. BP and heart rate were recorded. At the end of the protocol, the animals were euthanized and had their left ventricles sectioned for histological analysis (hematoxylin and eosin and picrosirius red). Results: RT did not attenuate the absolute and relative weight gains of the heart and left ventricle in the RT-SHR group compared with the sedentary group (SED-SHR). There was no difference in nuclear cardiomyocyte volume and collagen content between groups. However, RT decreased the number of nuclei in the cardiomyocytes and attenuated the increase in systolic BP in the RT-SHR when compared with the SED-SHR group. The Δ of the rate-pressure product was lower in the RT-SHR group compared with the groups SED-WKY and SED-SHR. Conclusions: The data obtained demonstrate that RT did not attenuate the cardiac hypertrophy, but reduced the nuclear proliferation in cardiomyocytes and the BP progression in SHRs with severe hypertension.
