Impaired vasodilator capacity and exaggerated pressor response to isometric exercise in subjects with family history of hypertension.

The nature of the cardiovascular response to isometric exercise is still debated. An adequate blood supply to exercising muscles at the onset of contraction seems to be an important factor controlling the extent of pressor response to isometric contraction. In comparison to normotensive subjects without familiar hypertensive history (F-), normotensive subjects with family history of hypertension (F+) have a reduced peripheral vasodilator capacity which impairs the possibility to adjust the muscular blood flow during exercise. An enhanced pressor response to handgrip test was observed in F+ and this hyperresponsivity was inversely related to the extent of forearm vasodilation capacity and largely prevented by the pretest increase of blood flow in exercising muscles. Our results suggest the importance of local vasodilating capacity as a determinant of reflex pressor response to isometric exercise.