Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks

The University of Alabama at Birmingham

Status: Completed

Conditions: Circadian Rhythm; Blood Pressure

Treatments: Other: Constant Routine Protocol

Study type: Interventional

Funder types: Other

Identifiers

NCT03934255

IRB-300003266

Details and patient eligibility

About

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.

Full 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.

Enrollment: 32 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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32 participants in 1 patient group

Constant Routine Protocol

Experimental group

Description:

Participants will be kept in constant conditions for 30 hours to observe circadian physiology in the absence of light, physical activity, and meals.

Treatment:

Other: Constant Routine Protocol