Physical exercise in essential hypertension.

Although several studies have shown that physical training lowers blood pressure values both in normotensives and in hypertensives, the mechanisms accounted for this effect are not clearly elucidated. It has been reported that the decrease in blood pressure and heart rate that accompanies physical training is associated not only with an increase in vagal tone but also with a reduction in plasma norepinephrine levels. Whether this reduction really means a decrease in sympathetic neural discharge is unknown, however. To clarify this issue, we have performed in 7 normotensives direct recording of postganglionic muscle sympathetic nerve activity from the peroneal nerve by microneurography before and after 10 weeks of an endurance training which increased oxygen consumption by 10%. It was shown that the blood pressure lowering effect of the training program was accompanied by a marked reduction in resting sympathetic nerve activity. These data provide the first direct evidence that in man, the blood pressure reduction induced by physical training is mediated by the neural sympathetic mechanisms.