THE ISOMETRIC EXERCISE-INDUCED ARTERIAL-HYPERTENSION TEST

The exercise tests used in the detection and follow-up of hypertensive patients fall into two categories: isotonic (dynamic) and isometric (static). The isometric exercise-induced arterial hypertension test consists of an isometric contraction - usually a grip by the dominant hand - sustained for 3 minutes, with a strength that is 30 percent of maximum voluntary strength. This results in a continuous and parallel increase of systolic and diastolic blood pressures during the hand grip. The heart rate also continuously rises, though not to the level obtained by the isotonic exercise test. The increase in cardiac output observed, despite a fall in stroke volume, and the absence of decrease in peripheral vascular resistance contribute to a sometimes considerable rise in blood pressure, particularly diastolic pressure. These cardiovascular responses do not depend on the muscular mass involved but on the relative strength developed during isometric contraction. Owing to the lack of strict standardization and longitudinal studies, the isometric exercise test is of little value in the early detection of arterial hypertension. However, it is useful in the follow-up of hypertensive patients, as it provides precise information on the point of impact and mode of action of several antihypertensive drugs.