Blood Pressure, Circadian Rhythm
Conditions
Brief summary
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.
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.
Interventions
Constant routine protocols are used in circadian research to examine underlying circadian rhythms in the absence of light, activity, and meals
Sponsors
American Heart Association
University of Alabama at Birmingham
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
Constant routine protocol in Blacks with dipping and non-dipping blood pressure
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Core body temperature phase | Core body temperature phase during a 30-hour constant routine protocol | Circadian phase of core body temperature recorded and transmitted wirelessly |
| Core body temperature amplitude | Core body temperature amplitude during a 30-hour constant routine protocol | Circadian amplitude of core body temperature recorded and transmitted wirelessly |
| Buccal cell mRNA expression | Expression of Bmal1 and Period 3 during a 30-hour constant routine protocol | Expression of Bmal1 and Period 3 obtained from buccal cell mRNA |
| Melatonin amplitude | Melatonin amplitude during a 30-hour constant routine protocol | Circadian amplitude of melatonin obtained from saliva |
| Melatonin phase | Melatonin phase during a 30-hour constant routine protocol | Circadian phase of melatonin obtained from saliva |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cortisol amplitude | Cortisol amplitude during a 30-hour constant routine protocol | Circadian amplitude of cortisol obtained rom saliva |
| Cortisol phase | Cortisol phase during a 30-hour constant routine protocol | Circadian phase of cortisol obtained rom saliva |
Countries
United States
Outcome results
None listed