1. Active orthostasis causes a fall of systolic blood pressure in the morning; this fall was more extensive in severe arterial hypertension.
2. Everyday physical activity produces a marked rise of systolic blood pressure, which is higher at noon and in the evening than in the morning; the hypertensive response is somewhat greater in WHO II and III, than in WHO I, grades of hypertension.
3. In studies on blood pressure behaviour in hypertensive subjects the circadian variability not only of the blood pressure at rest but also of the blood pressure response to various stimuli has to be considered.