Ambulatory blood pressure monitoring: assessing the diurnal variation of blood pressure.

The purposes of this paper are to examine the effects of activity, situation of measurement, mood, and occupation on the daily variation of blood pressure and to discuss the potential utility of ambulatory blood pressure monitoring in physical anthropological studies. The subjects of the blood pressure variability study are 125 men who were referred to the Hypertension Center at New York Hospital--Cornell Medical Center for evaluation of hypertension. There were 1,386 blood pressure measurements from these subjects available for study, which were taken using noninvasive ambulatory blood pressure monitoring techniques. Pressures were transformed to z scores using the subject's daily mean pressure and standard deviation to assess the relative elevation during the experience of the various factors. The results show that activity and mood are the most significant sources of blood pressure variation (P less than .005) and are additive. Occupation, which may be an indicator of social class in this population, also modified the mood effects. Because ambulatory blood pressure monitors obtain many readings over a day under a variety of circumstances, their use can improve epidemiological and human biological studies of the inheritance and variability of blood pressure. Ambulatory blood pressure monitoring is an important new tool in the study of human biological variation.