Circadian variations of blood pressure in patients with different degrees of hypertension. Changes induced by hypotensive treatment.

Arterial pressure was continuously recorded for 24--48 h in 3 normotensive subjects and in 60 hypertensive patients. The greatest variations occurred in those with labile, mild or moderate hypertension compared to those with severe hypertension or normal blood pressure. Atenolol (100-200 mg) administered once or twice daily produced a significant reduction of arterial pressure and a smaller response to the cold pressor test, hand grip and step test in patients with established hypertension, but little change in those with labile hypertension. The evening dose was not followed by a decrease in pressure greater than that observed without treatment, but determined a smaller rise on awaking.