Circadian blood pressure patterns and life stress

Abstract

Background: Scarce data are available on the influence of psychological aspects on 24-hour ambulatory blood pressure patterns either in normotensive or hypertensive subjects. This study was designed to evaluate the relationship between psychological profile and changes in daytime/nighttime blood pressure rhythm.

Methods: Nocturnal dipping was defined as the night/day ratio of ambulatory mean systolic and/or diastolic blood pressure < or =0.87. Three-hundred and two outpatients (M/F = 174/128; mean age = 49.8 years, SD = 13.6; range, 16-80 years) underwent 24-hour ambulatory blood pressure monitoring. They were administered a self-rating scale, the Psychosocial Index, as an indicator of stress, psychological distress, sleep disturbances, well-being, abnormal illness behavior and quality of life. There were 242 patients taking antihypertensive medication (146 adequately controlled and 96 not controlled) and 60 who were drug free (33 never-treated hypertensive and 27 normotensive subjects). Patients were divided according to the presence (n = 125) or absence (n = 177) of night blood pressure dipping. The two groups were compared using analysis of covariance, with age as a covariate.

Results: Dippers had lower (p < 0.001) nocturnal systolic and diastolic blood pressure than nondippers, and higher (p < 0.05) daytime diastolic blood pressure. Patients with nocturnal blood pressure decline had a markedly higher (p < 0.001) level of stress than nondippers. When the sample was divided according to the presence or absence of hypertension, only subjects with normal blood pressure showed nocturnal dipping associated with increased stressful life circumstances.

Conclusions: Our findings indicate that dippers experience stressful life circumstances, both in terms of life events and chronic stress. This suggests that stress-reducing techniques may be particularly helpful in the setting of hypertension characterized by nighttime blood pressure dipping.