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Sleep and Circadian Mechanisms in Hypertension

ConditionsHypertensionCardiovascular DiseasesCardiovascular Risk FactorsCircadian RhythmsSleep
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age25-64
SponsorOregon Health and Science University

About this trial

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 criteria

This trial does not accept healthy volunteers

Qualifiers

Ages 25-64

BMI 18.5-42kg/m2

Hypertension (average resting blood pressure between 130/80 mmHg and 160/100 mmHg)

Disqualifiers

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;

Trial design

Design model

Single group

Treatments tested in this trial

  • At-home Polysomnography

    Other intervention

    Participants will complete one night of unattended polysomnography in their home environment (SOMNOtouch RESP, SOMNOmedics America Inc., FL, USA).

  • Circadian Protocol

    Other intervention

    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.

  • Rested Wakefulness Trial

    Other intervention

    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.

  • Overnight Sleep Trial

    Other intervention

    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.

  • Regularized Sleep Schedule

    Behavioral

    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.

Treatment groups

32 Participants
are divided into 1 treatment group
Group A: Dipping vs non-dipping HTNExperimental treatment 5 interventions

Trial outcomes

Primary outcomes

1

Sleep duration (At-home Polysomnography)

Sleep duration will be scored from the ActiGraph and correlated with the sleep and activity diary. Sleep duration measures the amount of time asleep (in minutes).

Time frame
1-2 nights
2

Sleep Episodes (At-home Polysomnography)

Sleep episodes will be polysomnographically recorded and scored in 30-sec epochs for sleep stage, arousals, and respiratory events on SomnoMedics Domino Software. Values (based on software analysis) provide a description of what aspects of sleep are different between participants.

Time frame
1-2 nights
3

Blood pressure (Circadian and Overnight sleep vs. rested wakefulness trial)

Blood pressure (BP; systolic and diastolic) will be measured in a supine or semi-recumbent position. Investigators will measure beat-by-beat BP using a noninvasive device employing the volume-clamp method with hydrostatic correction. Investigators will measure BP using a calibrated sphygmomanometer to record sporadic BP at regular intervals throughout the protocols. Investigators will study circadian rhythms in blood pressure between people with dipping vs non-dipping hypertension. Investigators will also study how overnight sleep affects blood pressure in these groups. Investigators will also study ancillary variables such as morning surge in blood pressure. All blood pressure measurements will be measured in mmHg.

Time frame
7 days
4

Heart rate (Circadian and Overnight sleep vs. rested wakefulness trial)

Heart rate will be measured in beats-per-minute (bpm). This is a standard marker of cardiovascular health.

Time frame
7 days

Secondary outcomes

1

Ambulatory blood pressure (Sleep regularization trial)

Participants will be instructed to select a preferred bedtime time and ensure adherence to that time for 2-weeks. Investigators will not control sleep duration. After this trial, investigators will again measure 24-48 hour ambulatory BP. Both systolic and diastolic blood pressure will be measured in mmHg. Blood pressure dipping status will be assessed. BP dipping will be calculated as the percent reduction in average nighttime BP reduction compared to daytime BP. Blood pressure may be an indicator of cardiovascular health.

Time frame
2 weeks
2

Blood pressure dipping status (Sleep regularization trial)

Participants will be instructed to select a preferred bedtime time and ensure adherence to that time for 2-weeks. Investigators will not control sleep duration. Both systolic and diastolic blood pressure will be measured in mmHg. Blood pressure dipping status will be assessed. BP dipping will be calculated as the percent reduction in average nighttime BP reduction compared to daytime BP. Blood pressure dipping status may be an indicator of cardiovascular health.

Time frame
2 weeks

Other outcomes

Sponsors and contacts

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Oregon Health and Science University

Lead sponsor

Source ClinicalTrials.gov
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