Time-specified prediction limits for circadian blood pressure variability in clinical health

Hardware for automatic long-term measurement is wedded to a set of software modules in order to assess the status of human blood pressure circadian variability. To evaluate changes in blood pressure within a day, the authors analyzed 303 series of systolic and diastolic blood pressure and heart rate, automatically monitored every 30 minutes for at least 48 h from clinically healthy subjects, 19-23 yr of age. Individual circadian rhythm parameters computed for each time series by least-squares rhythmometry were used, first, for assessing rhythm characteristics of all subjects and each gender separately, and, second, for the computation of a so-called paradesm, a (here 90%) time-specified prediction region for the amplitude-acrophase pair. Original data were further used to compute time-specified prediction limits for blood pressure and heart rate in clinical health. Such reference limits may serve for an objective and positive definition of health, for the screening and diagnosis of disease, and for gauging the subject´s response to treatment