Reference values of ambulatory arterial pressure in activity and during the night. Multicenter study of 394 normotensive subjects at rest

The blood pressure pattern and variability were assessed in a population of 394 normotensive subjects (OMS) stratified by age (20 to 75 years) and sex. Ambulatory blood pressure measurements were performed with an automatic device (Spacelabs 5200) every 15 min. from 6 a.m. to 12 p.m., and every 30 min. from 0 a.m. to 6 a.m. The analysis was effected during normal daily activities (from 9 a.m. to 7 p.m.) and during night (from 11 p.m. to 7 a.m.). Blood pressure levels were higher in males than females. During daytime and nighttime, diastolic blood pressure rose with age until 59 years while SBP was not affected, except for the females older than 60 years. After this age, diastolic blood pressure decreased. No epidemiological study has provided a measure of the cardiovascular risk related to ambulatory blood pressure, so that we were unable to define true normal values. However, reference population values provided from two statistical methods: limit of the 95th upper confidence interval for the mean of limit of the 90th percentile value for the total data. These blood pressure distributions according to age and sex may allow a better approach to borderline hypertensive patients.