The precision of resting blood pressure measurement

By analysis of timed series of blood pressure(BP) measurements from a single individual, it was shown that data-averaging did not usually give a true value of resting systolic or diastolic pressure. Such measurements fitted a pattern of first order decay from an initial pressure towards a resting systolic or diastolic pressure, P. Using non-linear regression analysis it was possible to approach a standard error of 1 mmHg/1 mmHg for P values on a single day; the between-day dispersion, over a period of months, was found to be about 2 mmHg/2 mmHg. Computer analysis is required to give values of resting systolic and diastolic BP accompanied by error estimates.