Sleep and Circadian Contributions to Nighttime Blood Pressure (SCN-BP)

January 27, 2026 updated by: Stephen Justin Thomas, PhD, University of Alabama at Birmingham
Broadly, this study (SCN-BP) seeks to examine sleep and circadian factors that contribute to blood pressure levels at night.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

SCN-BP is imbedded in a parent grant titled "Improving the Detection of Hypertension (IDH-MEGA)" and examines a variety of sleep (e.g., sleep duration, timing, and the presence of sleep disorder) and circadian factors in Aims 1 and 2. In Aim 3, the investigators will conduct a 30-hour constant routine protocol to directly examine endogenous circadian and blood pressure rhythms. Aims 1 and 2 are purely observation. The study design design described below pertains the intervention piece of this study (Aim 3).

Study Type

Interventional

Enrollment (Estimated)

1427

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294-0017
        • University of Alabama at Birmingham

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Participant in the parent grant (IDH-MEGA)

Exclusion Criteria:

-

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Constant Routine Protocol
Participants complete a 30-hour constant routine protocol to directly examine markers of endogenous circadian rhythms. In a constant routine protocol, participants remain in a dimly lit room (<10 lux), in a semi-recumbent posture, remain awake, and consume iso-caloric snacks. Saliva samples are collected and core body temperature and blood pressure are measured.
Other: Constant Routine Protocol
A constant routine protocol is used to directly examine markers of circadian rhythmicity (e.g., melatonin and core body temperature). A constant routine protocol requires an individual to remain in a dimly lit room, in a constant semi-recumbent posture, and remain awake for more than 24 hours. It is one of two gold-standard research protocols for examining circadian rhythms in humans.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Melatonin
Time Frame: Hourly samples obtained over 30 hours
Melatonin levels obtained from saliva samples
Hourly samples obtained over 30 hours
Change in Core body temperature
Time Frame: Continuous measurements over 30 hours
Core body temperature
Continuous measurements over 30 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Blood pressure
Time Frame: Measurements obtained every 30 minutes over 30 hours
Systolic and diastolic blood pressure obtained using an ambulatory blood pressure monitor
Measurements obtained every 30 minutes over 30 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Alabama at Birmingham

Investigators

  • Principal Investigator: Stephen J Thomas, PhD, University of Alabama at Birmingham

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2023

Primary Completion (Estimated)

December 30, 2028

Study Completion (Estimated)

December 30, 2028

Study Registration Dates

First Submitted

November 18, 2022

First Submitted That Met QC Criteria

December 12, 2022

First Posted (Actual)

December 19, 2022

Study Record Updates

Last Update Posted (Actual)

January 29, 2026

Last Update Submitted That Met QC Criteria

January 27, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB-300010042

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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