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Purpose

This study is a mechanistic clinical trial designed to investigate the effects of the circadian system and sleep on non-dipping blood pressure (BP) in people with hypertension (HTN).

Conditions

Eligibility

Eligible Ages
Between 25 Years and 64 Years
Eligible Sex
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • Ages 25-64 - BMI 18.5-42kg/m2 - Hypertension (average resting blood pressure between 130/80 mmHg and 160/100 mmHg)

Exclusion Criteria

  • Over 5 pack-years of smoking; - Prior shift work within 12 months prior to the study; - Travel greater than three time zones for at least 3 months; - History of heart failure, cardiomyopathy, or history of bypass surgery, angioplasty, or previous myocardial infarction; - Acute or chronic diseases (except hypertension) that may affect outcome measures; - History of psychological conditions; - Sleep disorders, like severe sleep apnea, insomnia, etc.; - Prescription medications (Contraceptives and anti-hypertensive medications are permissible); - History of Illicit drug use and alcohol dependency; - 30 days free of cannabis use prior to the study; - Pregnancy; - Upper cut-off of 160/100 mmHg for BP

Study Design

Phase
N/A
Study Type
Interventional
Allocation
N/A
Intervention Model
Single Group Assignment
Intervention Model Description
All participants will complete all parts of the study. The order of completion of the second experiment (Overnight Sleep and Rested Wakefulness trials) will be randomized.
Primary Purpose
Other
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Dipping vs non-dipping HTN 		Participants will wear an ambulatory blood pressure monitor (SpaceLabs, Inc.) which will take their blood pressure in 20-30-minute intervals for 24-48 hours to determine blood pressure dipping status. All participants in this arm will complete the experiments in this order: 1. At-home polysomnography; 2. Constant Routine protocol; 3. Rested Wakefulness Trial AND Overnight Sleep Trial (Randomized crossover); 4. Sleep Regularization Trial
  • Other: At-home Polysomnography
    Participants will complete one night of unattended polysomnography in their home environment (SOMNOtouch RESP, SOMNOmedics America Inc., FL, USA).
  • Other: Circadian Protocol
    Participants will spend 4 days/3 nights in the laboratory to uncover circadian rhythms. After 2 nights for acclimatization and baseline measurements, participants will stay awake for 28 hours in dim light, constant temperature, and semi-recumbent posture. Participants will be provided with standardized snacks regularly. Polysomnography, core body temperature, sleep, finger oximetry, electrocardiogram (ECG), and beat-to-beat BP will (except microneurography) be measured throughout. Blood will be drawn every 2-4h to analyze catecholamines, renin activity, and aldosterone. All other measurements, including BP, heart rate (HR), and flow-mediated dilation will be performed regularly. Salivary samples will be collected every 2hrs (when awake) to analyze melatonin levels. A recovery sleep period will be provided and baseline testing procedures will be performed. Investigators may acquire direct recordings of sympathetic activity using microneurography.
    Other names:
    • Constant Routine
  • Other: Rested Wakefulness Trial
    Participants will start wearing an ambulatory BP monitor upon admission. Participants will be instrumented with full polysomnography (except leg myogram), and an intravenous catheter will be placed in the non-dominant arm. Participants will receive a standardized snack, and dinner ~4 hours before the start of the trial. Participants will be instrumented for microneurography. Participants will be awake in bed in dim light (<8 lux). An investigator will constantly be present in the control room to monitor and ensure constant supine posture and wakefulness. Polysomnography, beat-by-beat BP, and neurogram for microneurography will be done throughout each trial into awakening; blood will be sampled before, during, and immediately after each trial (total of 8 samples in each trial). Flow-mediated dilation will be conducted before bed and after bed. The two trials will be conducted ~one month apart to accommodate the menstrual cycle phase in pre-menopausal females.
    Other names:
    • Randomized crossover with overnight sleep trial
  • Other: Overnight Sleep Trial
    Participants will wear an ambulatory BP monitor upon admission. Participants will be instrumented with full polysomnography (except leg myogram), and an intravenous catheter will be placed in the non-dominant arm, and then participants will receive a standardized snack, and dinner 4 hours before the start of the trial. Polysomnography, beat-by-beat BP, and neurogram for microneurography will be done throughout each trial into awakening; blood will be sampled before, during, and immediately after each trial (total of 8 samples in each trial). Participants will be instrumented for microneurography. Participants will begin an 8-hour sleep opportunity (<0.1 lux) at their chosen sleep time. At the end of the sleep episode, participants will be gently awoken in a standardized fashion by use of a mild auditory stimulus. Flow-mediated dilation will be conducted before bed and after sleep. The two trials will be conducted one month apart to accommodate the menstrual cycle.
    Other names:
    • Randomized crossover with rested wakefulness trial
  • Behavioral: Regularized Sleep Schedule
    All participants will be asked to maintain a self-selected bedtime (sleep duration not controlled) for two weeks as an intervention after the completion of the constant routine and both the resting wakefulness and overnight sleep trials. During this time, participants will be asked to call a time-stamped voicemail box upon waking and going to bed, as well as complete a daily sleep diary and wear an Actigraph device on their wrist. Ambulatory blood pressure will be measured at home before and at the end of the two-week intervention.

Recruiting Locations

Oregon Health and Science University
Portland, Oregon 97239
Contact:
Saurabh S Thosar, PhD
503-494-2064
clinphys@ohsu.edu

More Details

Status
Recruiting
Sponsor
Oregon Health and Science University

Study Contact

Nicole Chaudhary, MPH
5034945536
clinphys@ohsu.edu

Detailed Description

This study is a mechanistic clinical trial designed to study the effects of the circadian system and sleep on non-dipping blood pressure (BP) in people with hypertension (HTN). Investigators will study participants with dipping and non-dipping hypertension. All participants will partake in all experiments. First, investigators will assess sleep in the participants' home environment using unattended polysomnography. Participants will then complete a 5-day overnight forced desynchrony laboratory protocol to uncover circadian rhythms (Constant Routine). The second experiment is a randomized crossover protocol. Two trials (Overnight Sleep and Rested Wakefulness) will be completed in randomized order to separate the effects of sleep on non-dipping blood pressure while assessing nighttime cardiovascular mechanisms. Finally, investigators will pilot test if 2 weeks of sleep regularization impacts 24-hour BP.

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.