Sleep and Circadian Mechanisms of Non-dipping Blood Pressure

Oregon Health and Science University30 enrolled

Overview

This study will be the first to distinguish the relative contributions of sleep, circadian and behavioral mechanisms to the non-dipping BP profile in Black adults and will lay the groundwork for optimizing therapies dependent on mechanisms, such as targeting sleep, targeting circadian rhythmicity, or targeting behaviors, and raising the possibility that ideal therapy for hypertension (HTN) may differ by race. This research will ultimately help to improve health and survival in black populations with HTN.

By studying standardized behaviors and regulators of BP during sleep and behavioral stresses across all circadian phases, this protocol will allow us specifically to: 1. To determine if poor sleep, while controlling for circadian phase, contributes to the higher overall BP and reduced nocturnal drop in BP in Blacks compared to Whites. 2. To determine if reduced BP responses to standardized behavioral changes across the day and night contribute to the higher overall BP and reduced nocturnal drop in BP in Blacks compared to Whites. 3. To determine if reduced circadian amplitude of BP contributes to the higher overall BP and reduced nocturnal drop in BP in Blacks compared to Whites.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Hypertension Cardiovascular Risk Factor

Interventions

Forced DesynchronyBEHAVIORAL

Participants will complete a 7-day circadian study protocol with numerous repeated blood pressure and other cardiovascular measures across the circadian cycle. All sleep opportunities and other activities will be scheduled by the experimenter so that by the end of the study these activities are spread evenly across all phases of the internal body clock.

Eligibility

Sex: ALLMin age: 30 YearsMax age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Self-identified Black or White * 'normotensive' (resting systolic blood pressure (SBP) \<140/90 mmHg) or uncomplicated stage 1 'hypertensive' (systolic BP between 140 and 160 mmHg or a diastolic (DBP) between 90 and 100 mmHg). * free of all prescription and non-prescription drugs (including caffeine, nicotine, alcohol and herbal medications) Exclusion Criteria: * Currently treated with pharmacologic agents for hypertension * Blood pressure \>160/100 mmHg * Smoked within the last year * Regular night work or rotating shift work for the three months prior to the study * Travel across more than three time zones during the three months prior to the study. * Any acute, chronic or debilitating medical conditions, other than mild hypertension (140\<SBP\<160 or 90\<DBP\<100 mmHg) and severe renal disease (glomerular filtration rate \<30) * Moderate to severe obstructive sleep apnea (OSA) * History of severe psychiatric illnesses or psychiatric disorders will be excluded, including alcoholism, drug dependency, major depression, manic depressive illness, schizophrenic disorders, panic disorder, generalized anxiety disorder, post-traumatic stress disorder, agoraphobia, claustrophobia, paranoid personality disorder, schizoid personality disorder, schizotypal personality disorder, borderline personality disorder, and antisocial personality disorder.

Locations (1)

Oregon Health & Science University

Portland, Oregon, United States

Outcomes

Primary Outcomes

Nighttime Systolic Blood Pressure

Systolic blood pressure measured via automatic sphygmomanometer every 30 minutes during sleep period at baseline. Readings recorded in units of mmHg.

Time frame: Baseline Night Average

Nighttime Diastolic Blood Pressure

Diastolic blood pressure measured via automatic sphygmomanometer every 30 minutes during sleep period at baseline. Readings recorded in units of mmHg.

Time frame: Baseline Night Average

Daytime Systolic Blood Pressure

Systolic blood pressure measured via automatic sphygmomanometer every 20 minutes during the daytime period at baseline. Readings recorded in units of mmHg.

Time frame: Baseline Daytime Average

Daytime Diastolic Blood Pressure

Diastolic blood pressure measured via automatic sphygmomanometer every 20 minutes during the daytime period at baseline. Readings recorded in units of mmHg.

Time frame: Baseline Daytime Average

Change in Systolic Blood Pressure Across Sleep Period

Change in systolic blood pressure per hour of scheduled sleep period measured via automatic sphygmomanometer every 30 minutes across each of the scheduled sleep periods while participants stayed 7-nights and days in the laboratory. Sleep was scheduled to occur at varied times across the entire circadian cycle so that the effects of the circadian cycle can be ignored (i.e., averaged out).

Time frame: 7 days in the laboratory

Change in Diastolic Blood Pressure Across Sleep Period

Change in diastolic blood pressure per hour of scheduled sleep period measured via automatic sphygmomanometer every 30 minutes across each of the scheduled sleep periods while participants stayed 7-nights and days in the laboratory. Sleep was scheduled to occur at varied times across the entire circadian cycle so that the effects of the circadian cycle can be ignored (i.e., averaged out).

Data from ClinicalTrials.gov

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