Sleep and Circadian Mechanisms of Non-dipping Blood Pressure

NCT03558893 | Completed Results

• 2 other identifiers: IRB 16803R35HL155681
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Hypertension; Cardiovascular Risk Factor

Keywords

circadian rhythm

Outcome Measures

Primary Outcomes (8)

• 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

Study Arms (2)

White Adults

OTHER

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

Black Adults

OTHER

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

Interventions

Forced Desynchrony BEHAVIORAL

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.

Black Adults; White Adults

Eligibility Criteria

• Age: 30 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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)

You may not qualify if:

• 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.

Sponsors & Collaborators

• Oregon Health and Science University: lead
• National Heart, Lung, and Blood Institute (NHLBI): collaborator

Study Sites (1)

Oregon Health & Science University

Portland, Oregon, 97239, United States

Location

MeSH Terms

Conditions

Hypertension

Condition Hierarchy (Ancestors)

Vascular Diseases; Cardiovascular Diseases

Limitations and Caveats

This is an observational study. Due to insufficient enrollment and an imbalanced group distribution, we do not have sufficient statistical power to fully interpret these data. The data are valuable as pilot data for future investigations and sample size estimation. While differences between White and Black participants were underpowered, in additional analyses we will examine effect of lifetime stress, as well as overall group circadian physiological responses to experimental conditions.

Results Point of Contact

• Title: Nicole P. Bowles
• Organization: Oregon Institute of Occupational Health Sciences, OHSU

bowlesn@ohsu.edu

503-494-4273

Study Officials

• Steven A Shea, PhD

  Ore

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Director

Study Record Dates

• First Submitted: June 5, 2018
• First Posted: June 15, 2018
• Study Start: December 1, 2018
• Primary Completion: December 31, 2024
• Study Completion: December 31, 2024
• Last Updated: July 20, 2026
• Results First Posted: June 16, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)