Does exercise help or hinder?

• Position: Hypertension

Researchers have identified one reason people with hypertension experience an even greater increase in their blood pressure when they exercise, and they have learned how to prevent the rise. A study in the Journal of Physiology reports that hypertensive individuals who exercise undergo decreased blood flow and oxygen in muscles. The scientists also identified a specific type of blood pressure medication that minimizes this effect.

"While there are many hypertension medications effective at lowering blood pressure at rest, very few are effective during exercise," points out Wanpen Vongpatanasin, lead author of the study. "People with above-normal readings need to exercise not only to help their blood pressure, but also their overall cardiovascular health?

Vongpatanasin indicates that some people with high blood pressure stop exercising out of fear of heart attack or stroke, and that sometimes physicians counsel those patients to limit activity because of those concerns. While it has been known that blood pressure increases during exercise in people with hypertension, a mechanism behind the action and a way to block it in humans had not been identified previously.

Vongpatanasin and colleagues had participants with mild hypertension and with normal blood pressure perform hand-grip exercises under regular conditions, followed by activity under conditions that affect a part of the nervous system that...