Behavioral treatment of high blood pressure. I. Analyses of intra- and interdaily variations of blood pressure during a one-month, baseline period

A group of 127 patients was enrolled in a study designed to evaluate the effectiveness of two behavioral treatments of high blood pressure, 'relaxation' and systolic blood pressure 'biofeedback'. All patients monitored their pressures three times daily and also had their pressures recorded by a health professional weekly for a one-month, baseline period. This article reports only the results from the baseline period. The main findings are: 1) extensive self-monitoring of blood pressure is feasible and practical; 2) systolic pressure rises throughout the day, but is highest in the afternoon; 3) diastolic pressure falls from morning to evening, but is highest in the afternoon; 4) intradaily range of systolic but not diastolic blood pressure is higher among women than among men; 5) both systolic and diastolic pressures fall throughout the first 3 weeks; 6) standard deviations and ranges of self-determined blood pressures are highly intercorrelated; however, changes in professionally measured blood pressures are poorly correlated with these indices of blood pressure lability; 7) systolic pressure levels, rates of decline throughout the baseline period and lability indices are correlated with age, but comparable measures of diastolic blood pressure are not correlated with age.