Increased response of blood pressure to rest and handgrip in subjects with essential hypertension.

The blood pressure (BP) response to supine rest for one hour and to an isometric handgrip exercise (3 min, 30%, of maximum) was investigated in 18 healthy normotensive men (N) (casual BP 117 +/- 6 / 73 +/- 5 mmHg, 39 +/- 3 years old) (mean +/- SD) and 50 men with essential hypertension (H) (162 +/- 13 / 105 +/- 9 mmHg, 41 +/- 4 years old). Casual BP was decreased by rest to resting BP (113 +/- 7 / 70 +/- 7 in N and 140 +/- 15 / 93 +/- 11 mmHg in H). H was divided into 3 groups of H-1 (resting BP of 124 +/- 7 / 80 +/- 4 mmHg), H-2 (137 +/- 9 / 92 +/- 4) and H-3 (154 +/- 10 / 104 +/- 4). The decreases in BP with rest were significantly greater in Groups H-1 (30 mmHg in systole / 20 mmHg in diastole, p less than 0.001), H-2 (23/11, p less than 0.001) and H-3 (16/8, p less than 0.001/0.05) as compared with those in N (4/3), and this decrease significantly correlated with the resting systolic BP in H (r = -0.601, p less than 0.001) and with diastolic BP (r = -0.604, p less than 0.001). The handgrip exercise increased BP (42/28, 55/35, 39/26 and 30/26 mmHg in Groups H-1, H-2, H-3 and N, respectively). The increase in systolic BP was significantly greater in Groups H-1, H-2 and H-3 than in N (p less than 0.001, p less than 0.001 and p less than 0.01, respectively), and the increase in diastolic BP was significantly greater in Group H-2 than in N (p less than 0.05), but not in Groups H-1 and H-3. The significant decrease in BP with rest and the significant increase in BP by the exercise may represent the pathophysiological nature of the cardiovascular response in the early stage of essential hypertension.