Purpose

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.

Conditions

Eligibility

Eligible Ages
Over 18 Years
Eligible Genders
All
Accepts Healthy Volunteers
Yes

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

Study Design

Phase
N/A
Study Type
Interventional
Allocation
N/A
Intervention Model
Single Group Assignment
Intervention Model Description
Constant routine protocol in Blacks with dipping and non-dipping blood pressure
Primary Purpose
Basic Science
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Constant Routine Protocol
Participants will be kept in constant conditions for 30 hours to observe circadian physiology in the absence of light, physical activity, and meals.
  • Other: Constant Routine Protocol
    Constant routine protocols are used in circadian research to examine underlying circadian rhythms in the absence of light, activity, and meals

Recruiting Locations

University of Alabama at Birmingham
Birmingham, Alabama 35294-0017
Contact:
Stephen J Thomas, PhD
205-934-3367
sjthoma@uabmc.edu

More Details

Status
Recruiting
Sponsor
University of Alabama at Birmingham

Study Contact

Stephen J Thomas, PhD
205-934-3367
sjthoma@uabmc.edu

Detailed Description

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.

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.