Stress, Salt Excretion, and Nighttime Blood Pressure

Blood pressure (BP) has a diurnal rhythm; it is normally highest during the daytime period and lowest during the nighttime period (BP dipping). The diurnal pattern of BP over a 24-hour period can be assessed using ambulatory BP monitoring (ABPM). Evidence indicates that an abnormal diurnal pattern of BP on ABPM, defined by reduced BP dipping or elevated nighttime BP, is associated with an increased risk of cardiovascular disease (CVD) events. Psychological stress occurs when an individual perceives that the environmental demands exceed his/her adaptive capacity. An individual's response to events that are representative of this overload, such as perceived stress and negative affect including anger, hostility, depression, vital exhaustion, and symptoms of posttraumatic stress disorder, are associated with reduced BP dipping and/or higher nighttime BP. Exposure to environmental factors which tax an individual's ability to cope, including lower socioeconomic status, job strain, and perceived racism, are also associated with reduced BP dipping and/or higher nighttime BP. This study will examine the disruption of the normal diurnal pattern of sodium excretion by psychological stress as a novel biological mechanism underlying an abnormal diurnal pattern of BP. The study will be conducted both in the laboratory and in the naturalistic environment with a multi-ethnic sample of 211 adult community participants from upper Manhattan who do not have a history of CVD, diabetes, chronic kidney disease, or another major medical condition and are not taking antihypertensive medication. During a laboratory visit, urinary sodium excretion in response to mental stress tasks will be examined.