Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks

  • End date
    Mar 31, 2023
  • participants needed
  • sponsor
    University of Alabama at Birmingham
Updated on 13 April 2022
Accepts healthy volunteers


This study seeks to examine central and peripheral circadian mechanisms in Blacks with appropriately dipping systolic blood pressure (blood pressure that dips by at least 10%) compared with non-dipping systolic blood pressure (blood pressure that dips by less than 10%) using a constant routine protocol. Constant routine protocols are commonly used in the field of circadian biology to examine rhythms in biological processes while controlling the entraining effects of light, activity, and diet.


This study will enroll a total of 40 participants (n=20 non-dippers; n=20 dippers) to complete a 30-hour constant routine protocol. Participants will undergo baseline testing that includes anthropometric measurements, clinic blood pressure measurements, completion of self-report questionnaires on sleep and mood, be fitted with an ambulatory blood pressure monitor and actigraphy watch, and be provided with home sleep testing (HST) equipment.

Following completion of baseline assessment, eligible participants will be scheduled for the 30-hour constant routine protocol. The 30-hour constant routine protocol will allow for the hourly collection of saliva, collection of buccal cells every 4 hours, and constant monitoring of core body temperature, all of which are primary outcomes in the assessment of central and peripheral circadian clock markers. Amplitude and phase of these outcomes will be assessed in non-dippers versus dippers.

Condition Circadian Rhythm, Blood Pressure
Treatment Constant Routine Protocol
Clinical Study IdentifierNCT03934255
SponsorUniversity of Alabama at Birmingham
Last Modified on13 April 2022


Yes No Not Sure

Inclusion Criteria

Black or African American race
Age 18 years or older

Exclusion Criteria

Work alternating or night shifts
Pregnant or nursing
Current illicit drug use
History of severe mental illness
Medical conditions that would be contraindicated for a constant routine protocol
Take anti-hypertensive medications or beta-blockers
Severe obstructive sleep apnea
Clear my responses

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Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

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If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

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Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

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