Intra-Arterial Blood Pressure Response in Hypertensive Subjects during Low- and High-Intensity Resistance Exercise

OBJECTIVE: The aim of this study was to describe blood pressure responses during resistance exercise in hypertensive subjects and to determine whether an exercise protocol alters these responses. INTRODUCTION: Resistance exercise has been recommended as a complement for aerobic exercise for hypertensive patients. However, blood pressure changes during this kind of exercise have been poorly investigated in hypertensives, despite multiple studies of normotensives demonstrating significant increases in blood pressure. METHODS: Ten hypertensive and ten normotensive subjects performed, in random order, two different exercise protocols, composed by three sets of the knee extension exercise conducted to exhaustion: 40% of the 1-repetition maximum (1RM) with a 45-s rest between sets, and 80% of 1RM with a 90-s rest between sets. Radial intra-arterial blood pressure was measured before and throughout each protocol. RESULTS: Compared with normotensives, hypertensives displayed greater increases in systolic BP during exercise at 80% (+80&plusmn;3 vs. +62&plusmn;2 mmHg, P<0.05) and at 40% of 1RM (+75&plusmn;3 vs. +67&plusmn;3 mmHg, P<0.05). In both exercise protocols, systolic blood pressure returned to baseline during the rest periods between sets in the normotensives; however, in the hypertensives, BP remained slightly elevated at 40% of 1RM. During rest periods, diastolic blood pressure returned to baseline in hypertensives and dropped below baseline in normotensives. CONCLUSION: Resistance exercise increased systolic blood pressure considerably more in hypertensives than in normotensives, and this increase was greater when lower-intensity exercise was performed to the point of exhaustion

Acute and Chronic Effects of Aerobic and Resistance Exercise on Ambulatory Blood Pressure

Hypertension is a ubiquitous and serious disease. Regular exercise has been recommended as a strategy for the prevention and treatment of hypertension because of its effects in reducing clinical blood pressure; however, ambulatory blood pressure is a better predictor of target-organ damage than clinical blood pressure, and therefore studying the effects of exercise on ambulatory blood pressure is important as well. Moreover, different kinds of exercise might produce distinct effects that might differ between normotensive and hypertensive subjects

Intra-arterial blood pressure response during resistance exercise of different intensities in hypertensives treated with atenolol

O exercício resistido dinâmico é recomendado, em complemento ao aeróbico, para indivíduos hipertensos. O aumento da pressão arterial durante sua execução se faz, primordialmente, pelo aumento da resistência vascular periférica, porém o aumento do débito cardíaco também parece estar envolvido. A elevação da pressão arterial parece ser exacerbada em hipertensos não medicados. Entretanto, grande parte dos hipertensos está sob terapêutica medicamentosa e vários fazem uso de -bloqueadores, que reduzem o débito cardíaco pela diminuição da resposta taquicárdica e inotrópica à estimulação simpática. Assim, é possível supor que o uso de -bloqueadores reduza o aumento da pressão arterial nos exercícios resistidos. Porém, pelo nosso conhecimento, este efeito ainda não foi estudado. Assim, esta investigação teve por objetivo investigar o efeito do atenolol sobre a resposta da pressão arterial durante o exercício resistido de diferentes intensidades. Foram estudados 10 hipertensos essenciais com pressão arterial sistólica/diastólica sob placebo entre 140 e 160/90 e 105 mmHg. Os pacientes foram estudados após 6 semanas de uso de placebo e de atenolol, sendo que os indivíduos estavam cegos para a medicação. Em cada fase, os voluntários fizeram o exercício de extensão de joelhos na cadeira extensora até a exaustão, seguindo 3 protocolos realizados em ordem aleatória: a) uma série em 100% de 1RM (repetição máxima), b) três séries em 40% de 1RM e; c) três séries em 80% de 1RM. Antes, durante e após os exercícios, a pressão arterial foi medida diretamente na artéria radial. Os dados foram comparados pelo teste t student ou pela ANOVA de dois fatores para amostras repetidas. Quando necessário, foi utilizado o post-hoc de Newman-Keuls e aceito como significante o índice de P&#8804;0,05. Verificou-se que o atenolol reduziu os valores absolutos atingidos pela pressão arterial sistólica durante a execução do exercício nas três intensidades (valores máximos: 100% = 186&#177;4 vs. 215&#177;7, 80% = 224&#177;7 vs. 247&#177;9 e 40% = 223&#177;7 vs. 252&#177;16, mmHg, P&#8804;0,05). Além disso, ele reduziu o aumento desta pressão arterial na 1ª série do exercício nas 3 intensidades (100% = +38&#177;5 vs. +54&#177;9; 80% = +68&#177;11 vs. +84&#177;13 e 40% = +69&#177;7 vs. +84&#177;14, mmHg, P&#8804;0,05). Em relação à pressão arterial diastólica, o atenolol diminuiu os valores máximos absolutos e o aumento desta pressão arterial (126&#177;6 vs. 145&#177;6 e +41&#177;6 vs. +52&#177;6, mmHg, P&#8804;0,05) no exercício em 100% de 1RM, mas não a alterou nas demais intensidades. Dessa forma, é possível concluir que o atenolol foi eficaz em atenuar tanto o valor absoluto quanto a resposta da pressão arterial sistólica durante o exercício resistido de diferentes intensidades em hipertensos, conferindo-lhes uma certa proteção cardiovascular. Este achado reforça o conceito de que o aumento do débito cardíaco é um mecanismo importante para o aumento da pressão arterial sistólica durante este tipo de exercícioDynamic resistance exercise is recommended in association to aerobic exercise for hypertensive patients. Blood pressure increase during this kind of exercise is mainly due to an increase in peripheral vascular resistance, however, an increase in cardiac output might also be involved. This blood pressure increase seems to be exacerbated in non-medicated hypertensives. Nevertheless, most of the hypertensives are taking medications, and some of them are receiving -blockers, which decreases cardiac output by the inhibition of sympathetic-induced increase on heart rate and cardiac contractility. Thus, -blockers might decrease blood pressure rise during resistance exercise which, to our knowledge, has not been studied yet. Hence, the aim of this study was to verify the effects of the selective -blocker atenolol on blood pressure increase during dynamic resistance exercise of different intensities. Ten essential hypertensives with systolic/diastolic blood pressures under placebo condition maintained among 140 and 160/90 and 105 mmHg were recruited. These volunteers were studied after 6 weeks of placebo and atenolol treatment, and they were blinded for the medication used. In each phase, the volunteers executed, in a random order, 3 protocols of knee extension exercise until fatigue: a) 1 set at 100% of 1 repetition maximum (1RM); b) 3 sets at 40% of 1RM; c) 3 sets at 80% of 1RM. Before, during and after the exercises, intra-arterial radial blood pressure was measured. Data were compared by paired student t-test and by two-way ANOVA for repeated measures. Newman-Keuls post-hoc test was applied when necessary. P&#8804;0.05 was considered as significant. Atenolol decreased the absolute value achieved by systolic blood pressure during the exercise performed at the 3 intensities (maximum values: 100% = 186&#177;4 vs. 215&#177;7, 80%= 224&#177;7 vs. 247&#177;9 e 40% = 223&#177;7 vs. 252&#177;16, mmHg, P&#8804;0.05). Moreover, atenolol also reduced systolic blood pressure increase in the first set of exercise at the 3 intensities (100% = +38&#177;5 vs. +54&#177;9; 80% = +68&#177;11 vs. +84&#177;13 e 40% = +69&#177;7 vs. +84&#177;14, mmHg, P&#8804;0.05). In regard to diastolic blood pressure, atenolol decreased its absolute values and its increase during exercise performed at 100% of 1RM (126&#177;6 vs. 145&#177;6 e +41&#177;6 vs. +52&#177;6, mmHg, P&#8804;0.05), but it did not change diastolic blood pressure at the other exercise intensities. In Conclusion, atenolol therapy was effective in reducing both, systolic blood pressure absolute values and increase during resistance exercise of different intensities in hypertensive subjects; given them some cardiovascular protection. This result enhances the belief that cardiac output increase is important for blood pressure enhancement during this kind of exercis