Self-measurement and ambulatory monitoring of blood pressure: a subject's chronobiological perspective.

Population studies show the direct benefit from self-measurement for guiding the treatment of patients with severe hypertension; they also separate groups of children with a positive vs. negative family history of high blood pressure, despite the difficulty of obtaining valid readings during the rest/sleep span, which are needed for a reliable estimation of the circadian parameters. From the viewpoint of preventive maintenance, a 67-year-old woman monitored her blood pressure and heart rate around the clock for 7 days, using concomitantly an ambulatory monitor and a manual instrument. Self-measurement profiles were repeated on several occasions. The results are compared with those of a 62-year-old woman who followed the same initial 7-day protocol. The estimation of the circadian blood pressure pattern differed between the profiles obtained with an ambulatory monitor and by self-measurement. The differences, relatively small in one subject, were much larger for the other subject. Provided the results are chronobiologically analyzed and interpreted in the light of reference limits which are specific to self-measurement series as well as for gender, age and times of sampling, systematic self-measurement of blood pressure may yield a reliable assessment of the circadian variation for some, but not for all, individuals. For those who have been validated in at least one 7-day/24-h profile, occasional automatic ambulatory profiles are tentatively recommended as the main approach, with complementary systematic self-measurement when automatic instruments are scarce. For those with discrepant results, automatic monitoring is invariably recommended.