Sleep and Circadian Mechanisms in Hypertension
Oregon Health and Science University
32 participants
Aug 4, 2022
INTERVENTIONAL
Conditions
Summary
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).
Eligibility
Inclusion Criteria3
- Ages 25-64
- BMI 18.5-42kg/m2
- Hypertension (average resting blood pressure between 130/80 mmHg and 160/100 mmHg)
Exclusion Criteria12
- 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;
- days free of cannabis use prior to the study;
- Pregnancy;
- Upper cut-off of 160/100 mmHg for BP
Interventions
Participants will complete one night of unattended polysomnography in their home environment (SOMNOtouch RESP, SOMNOmedics America Inc., FL, USA).
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.
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.
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.
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.
Locations(1)
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NCT05184933