Sleep and Circadian Mechanisms of Non-dipping Blood Pressure

Sleep and Circadian Mechanisms Contributing to Nocturnal Non-dipping Blood Pressure

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.

Study Overview

• Status: Completed
• Conditions: Hypertension; Cardiovascular Risk Factor
• Intervention / Treatment: Behavioral: Forced Desynchrony

Detailed Description

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
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Oregon
    • Portland, Oregon, United States, 97239
      • Oregon Health & Science University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes

Study Population

Black and White adults.

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: White Adults; White adults aged 30-60 with a BMI of 18.5<BMI<40 kg/m2 who are non-smokers (≥1 year), not on prescription medications (except oral contraceptives), and have had no recent shift work or major travel. Mild, unmanaged hypertension (below 160/100) and renal disease are allowed.	Behavioral: Forced Desynchrony; 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.
Other: Black Adults; Black adults aged 30-60 with a BMI of 18.5<BMI<40 kg/m2 who are non-smokers (≥1 year), not on prescription medications (except oral contraceptives), and have had no recent shift work or major travel. Mild, unmanaged hypertension (below 160/100) and renal disease are allowed.	Behavioral: Forced Desynchrony; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	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).	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).	7 days in the laboratory
Circadian Amplitude of Systolic Blood Pressure When Awake	Systolic blood pressure was assessed manually via sphygmomanometry during each scheduled wakefulness period while participants stayed 7-nights and days in the laboratory. Behaviors during wakefulness were standardized and scheduled to occur across the entire circadian cycle. Any systematic circadian rhythmicity was assessed by analysis of variance which revealed the underlying amplitude of the circadian rhythm of systolic blood pressure while controlling for (averaging out) any ongoing behaviors.	7 days in the laboratory
Circadian Amplitude of Diastolic Blood Pressure When Awake	Diastolic blood pressure was assessed manually via sphygmomanometry during each scheduled wakefulness period while participants stayed 7-nights and days in the laboratory. Behaviors during wakefulness were standardized and scheduled to occur across the entire circadian cycle. Any systematic circadian rhythmicity was assessed by analysis of variance which revealed the underlying amplitude of the circadian rhythm of diastolic blood pressure while controlling for (averaging out) any ongoing behaviors.	7 days in the laboratory

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
venous epinephrine	Venous epinephrine will be measured for adrenal cortex contribution to sympathetic activity.	7-day lab stay
venous norepinephrine	venous norepinephrine will be measured for sympathetic nerve activity's contribution to sympathetic activity.	7-day lab stay
saliva cortisol	Saliva cortisol will be measured as a sympathetic potentiating hormone.	7-day lab stay
saliva melatonin	saliva melatonin will be measured as a sympathetic attenuating hormone.	7-day lab stay
venous aldosterone	venous aldosterone will be measured as an end point of renin-angiotensin and sympathetic nerve activation	7-day lab stay
venous endocannabinoids	venous endocannabinoids will be measured to estimate stress habituation.	7-day lab stay
flow mediated dilation	Flow mediated dilation will be measured as an indication of endothelial function.	7-day lab stay
beat-by-beat blood pressure	Beat-by-beat Blood Pressure will be measured in the fingers using a non-invasive blood pressure monitoring device.	7-day lab stay
24-hr ambulatory blood pressure	Ambulatory blood pressure will be measured with an automatic 24-hr blood pressure monitoring device to estimate of blood pressure dipping status.	2 day ambulatory period

Collaborators and Investigators

• Sponsor: Oregon Health and Science University
• Collaborators: National Heart, Lung, and Blood Institute (NHLBI)
• Investigators: Principal Investigator: Steven A Shea, PhD, Ore

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2018
• Primary Completion (Actual): December 31, 2024
• Study Completion (Actual): December 31, 2024

Study Registration Dates

• First Submitted: June 5, 2018
• First Submitted That Met QC Criteria: June 5, 2018
• First Posted (Actual): June 15, 2018

Study Record Updates

• Last Update Posted (Actual): July 20, 2026
• Last Update Submitted That Met QC Criteria: June 23, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: circadian rhythm
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Hypertension
• Other Study ID Numbers: IRB 16803; R35HL155681 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No