We carried out both mental stress (MS) and isometric handgrip exercise (IHG) tests in 20 mild hypertensive patients to compare responses of blood pressure, heart rate, blood cell count and pressor hormones between the two tests. Increments of blood pressure and heart rate by MS (mean±SEM, 42± 2/17±1mmHg and 8±1beats/mm) were similar to those by IHG (39 ±3/17±2mmHg and 6±1beats/ min). Packed cell volume, erythrocytes, leukocytes, and platelets significantly increased in the MS test (1.3±0.3%, 1.7±0.3%, 10.3±2.1% and 2.8±1.6%, respectively) and in the IHG test (1.3±0.3%, 1.0 ±0.3%, 6.2±1.2% and 1.9±0.8% respectively). In both tests the percent increase was significantly greater in leukocytes than in erythrocytes and platelets (p<0.01). A comparison between the two tests revealed that the increase in leukocyte count was significantly greater in the MS than in the IHG test (p <0.05). Plasma noradrenaline, adrenaline and vasopressin levels significantly increased in both tests and there were no significant differences in responses of these pressor hormones between the two tests. Plasma active renin and aldosterone levels significantly increased in the MS test, but remained unchanged in the IHG test. Although the responses to both stressors are mainly induced by the sympathoadrenal excitation, there are some differences in details between the two tests. We concluded that MS induced a greater increase in leukocyte count than IHG with equipressor response and activated the renin-angiotensin-aldosterone system, which was not stimulated by the latter. (Hypertens Res 1992; 15: 33-39)
