Circadian Variation in Blood Pressure in Elderly Hypertensive Patients.

We studied circadian variation in blood pressure in elderly patients with hypertension, using three criteria for "non-dipper". Ambulatory blood pressure monitoring was done in 107 elderly outpatients whose average 24-hour systolic blood pressure was greater than 140 mmHg. Daytime was distinguished from nighttime by the level of physical activity as measured with an activity sensor and a questionnaire. The three criteria for "non-dipper" were as follows: 1. A nocturnal decline in systolic blood pressure that was less than 10% of the daytime average blood pressure. 2. A nocturnal decline in systolic blood pressure that was less than 10 mmHg. 3. A nighttime average systolic blood pressure that was greater than the daytime average systolic blood pressure. The nocturnal decrease in blood pressure was smaller in older patients than in younger patients. In patients over 80 years old, it was 6.0 mmHg (p < 0.05, as compared with patients aged 60-69 and with patients aged 70-79). The percentages of patients classified as "non-dippers" according to the criteria listed above were 53.3%, 37.4%, and 15.9%, respectively. Older patients were more likely than younger patients to be classified as "non-dippers". When defined according to criterion # 1, "non-dippers" made up 83.3% of those over 80 years old. These results was consistent with a continuous age-related decline in neuroendocrine regulation involving both peripheral and central nervous system.