Sleep and Circadian Mechanisms in Hypertension

Overview

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).

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.

Interventions

• 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
• 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
• 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
• 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

Primary outcome measures

• Sleep duration (At-home Polysomnography) [Time frame: 1-2 nights]
• Sleep Episodes (At-home Polysomnography) [Time frame: 1-2 nights]
• Blood pressure (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]
• Heart rate (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]
• Heart rate variability (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]
• Epinephrine (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]
• Norepinephrine (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]
• Aldosterone (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]
• Renin (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]
• Vascular endothelial function (Circadian and Overnight sleep vs. rested wakefulness trial) [Time frame: 7 days]

Secondary outcome measures (2)

• Ambulatory blood pressure (Sleep regularization trial) [Time frame: 2 weeks]
• Blood pressure dipping status (Sleep regularization trial) [Time frame: 2 weeks]

Eligibility criteria

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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Other

Study locations

United States · 1 center

• Oregon Health and Science University — Portland

Identifiers

NCT: NCT05184933 · IRB00023776

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗