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Abstract-Physical exercise increases insulin sensitivity in conditions associated with insulin resistance, such as obesity and diabetes, but little is known in this regard in hypertension. Whether postexercise changes in hemodynamics and/or changes in insulin-induced vasodilatation could contribute to a postexercise increase in insulin sensitivity in hypertensive subjects is unknown. We investigated the effects of acute physical exercise on insulin sensitivity in 10 hypertensive and 10 normotensive subjects during a control evaluation (CTRL), during lower body negative pressure (LBNP), after 30 minutes of mild bicycle exercise (POSTEX), and during LBNP after exercise (POSTEXϩLBNP). Insulin-induced vasodilatation was assessed from peak forearm blood flow during the intravenous glucose tolerance test. Cardiac output (4.9Ϯ0.3 versus 5.3Ϯ0.4 L/min, meanϮSEM) and insulin sensitivity (the glucose disappearance rate over insulin area under the curve: 0.91Ϯ0.07 versus 1.38Ϯ0.25 min Ϫ1 /[pmol · L Ϫ1 ] · minute) were lower (both PϽ0.05) in hypertensive than in normotensive subjects, respectively. Cardiac output decreased during LBNP, increased during POSTEX, and was similar to control during POSTEXϩLBNP in both groups. Insulin sensitivity was unchanged during LBNP, increased during POSTEX, and remained elevated during POSTEXϩLBNP in hypertensive subjects, whereas it remained unchanged in normotensives. Peak forearm blood flow was significantly lower in hypertensive than in normotensive subjects, despite higher insulin levels in hypertensives, and was not modified by LBNP or exercise. In conclusion, insulin sensitivity increases after exercise in hypertensive subjects, and the increase in cardiac output does not contribute to this effect. Endogenous insulin-induced vasodilatation is reduced in hypertensive subjects, and this insulin action is not affected by physical exercise.

To verify whether there are relationships between vascular and hormonal responses to aerobic training in hypertensive persons, sedentary hypertensive patients were randomized to an aerobic training or a callisthenic exercise group. The patients' 24-hour blood pressure, arterial compliance, forearm blood flow, and hormonal profile were evaluated at baseline and after 3-month training protocols. Mean maximal oxygen consumption (VO 2 max) increased by 8% in the aerobic group (P<.001), while no change was observed in the control group. There was a decrease in insulin resistance (homeostatic model assessment of insulin resistance, P=.039) and plasma cortisol (P=.006) in the aerobic group only, that also demonstrated an increase in forearm blood flow (P<.001) after training. No relationship was observed between change in blood pressure or change in body mass and other parameters. Aerobic training can promote a decrease in cardiovascular risk in hypertensive adults by improving vascular function and insulin resistance, despite no changes in ambulatory blood pressure after a 3-month intervention. J Clin Hypertens (Greenwich). 2011;13:89-96. H ypertension is an enormous public health challenge in both industrialized and developing countries, and it is the most important risk factor for cardiovascular (CV) diseases.1 Physical exercise is recommended to help reduce blood pressure (BP) and lower the risk for developing CV disease.2 A recent meta-analysis 3 of randomized controlled trials showed that in a hypertensive population, endurance training reduced resting systolic and diastolic BP by 6.9 mm Hg and 4.9 mm Hg, respectively, and ambulatory systolic BP and diastolic BP (4 studies, 5 groups) decreased by 3.4 mm Hg and 2.7 mm Hg, respectively. Despite this apparent reduction, changes in ambulatory systolic BP were nonsignificant in 3 groups, whereas reductions in diastolic BP were nonsignificant in 4 groups of these studies. These disparate results might be partially explained by methodologic differences, including small sample sizes and poor supervision of prescribed training intensity. Ambulatory BP (ABP) may be the more appropriate method of monitoring BP in exercise studies because, unlike office BP, it is not influenced by the ''white coat effect'' during treatment, placebo-induced hypotension, and regression to the mean phenomenon.

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OBJETIVO: Analisar o comportamento de pressão arterial (PA) e a freqüência cardíaca (Fc) de indivíduos ao longo da jornada de trabalho em dois ambientes com estresses ambientais distintos. MÉTODOS: Foram avaliados 46 funcionários, trabalhadores de uma indústria processadora de madeira, de Botucatu, SP, sendo 27 funcionários da linha de produção (esforço físico moderado-intenso, altas temperaturas e elevados níveis de ruído) (G1), e 19 da administração (sem esforço físico, salas aclimatadas, baixos níveis de ruído) (G2). Todos foram submetidos a avaliação antropométrica da composição corporal (obesidade e adiposidade) e bioquímica do sangue (lipidemia) e, adicionalmente, o registro da PA e da Fc em três momentos do turno de serviço: início, meio e fim. RESULTADOS: Houve semelhança na variação da PA entre G1 e G2, mas com maiores elevações de PA e Fc em G1. Os resultados mostraram grande variabilidade na resposta da PA, levando à subdivisão dos grupos G1 e G2 em respondedores (GR, aumento maior de 10% na PA média) e não respondedores (GN). Os subgrupos GR e GN apresentaram semelhanças nos padrões antropométrico e bioquímico diferindo apenas na resposta pressórica e no caso do GR1 na história familiar de hipertensão. Comparando os subgrupos GR1 e GR2, foi constatado que os primeiros apresentaram maiores variações de PA e Fc que os segundos. CONCLUSÕES: A variação individual da resposta pressórica e da Fc conforme o tipo de estresse ambiental indica ser este um fator adicional a ser considerado na avaliação da pressão arterial e, talvez, na gênese da hipertensão arterial de operários.