NCT06535178 · Oregon Health and Science University
The Influence of Sleep on Cardiovascular Outcomes
(DISCO)
What this study is about
The goal of this study is to identify the effects of sleep regularity on cardiovascular regulatory mechanisms. The investigators are hoping to discover if improving the regularity of sleep timing will improve metabolic and vascular health markers.
View original scientific description
The goal of this study is to identify the effects of sleep regularity on cardiovascular regulatory mechanisms. The investigators are hoping to discover if improving the regularity of sleep timing will improve metabolic and vascular health markers. The protocol is a 12-week prospective cohort study that includes both field and in-laboratory data collection in ostensibly healthy male and female adults, aged 18-40years. We will also have a sub-group of individuals with chronic pain to examine the effects of sleep regularity on pain outcomes.
Interventions
BEHAVIORAL
Sleep Regularity Group
Maintained consistent sleep onset time (±30 min self-selected sleep time) for 12-weeks.
Primary outcome measures
Changes in dim-light melatonin onset
Time frame: Week 0 and Week 12
Saliva samples will be collected pre- and post-12-week intervention and will be assayed for melatonin using standardized assays. Dim-light melatonin onset will be calculated using the linear interpolated point in time in which each participant's melatonin crosses and remains elevated above a 4pg/mL threshold. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in SRI
Time frame: Week 0 and Week 12
SRI will be calculated from 2-weeks actigraphy data prior to the first in-laboratory visit. Changes in SRI will be measured for 2-weeks during Weeks 1-2, Weeks 6-7, and Weeks 11-12 for the intervention group and during Weeks 11-12 for the control group. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in vascular endothelial function
Time frame: Week 0 and Week 12
Vascular endothelial function will be assessed via flow mediated dilation pre- and post-12-week intervention. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in heart rate
Time frame: Week 0 and Week 12
Heart rate will be measured every \~30 minutes via a blood pressure cuff. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in blood pressure
Time frame: Week 0 and Week 12
Changes in resting blood pressure will be measured every \~30 minutes via ambulatory blood pressure machines for up to 48-hours during Weeks 1-2, Weeks 6-7, and Weeks 11-12 for the intervention group and Weeks 11-12 for the control group. Blood pressure patterns during the day and night will be assessed, as well as a contrast of day and nighttime blood pressure levels. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in resting cardiac vagal tone
Time frame: Week 0 and Week 12
High frequency power of the heart rate variability power spectrum will be used to estimate cardiac parasympathetic activity (vagal tone). These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in heart rate response to exercise
Time frame: Week 0 and Week 12
Beat by beat heart rate will be recorded during a Monark bicycle ergometer exercise test where workload will be increased every 3-min until \~75% age predicted heart rate max is achieved. Heart rate will be averaged at rest, during each 3-min stage, and each minute during a 2-minute recovery. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in blood pressure response to exercise
Time frame: Week 0 and Week 12
Beat by beat blood pressure will be recorded during a Monark bicycle ergometer exercise test. Blood pressure will be averaged at rest, during each 3-min stage, and each minute during a 2-minute recovery. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in energy metabolism
Time frame: Week 0 and Week 12
Resting energy expenditure and macronutrient oxidation will be measured via indirect calorimetry. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Changes in glucose
Time frame: Week 0 and Week 12
Changes in glucose will be measures during Weeks 1-2, Weeks 6-7, and Weeks 11-12 for the intervention group and Weeks 11-12 for the control group. These data will be used to calculate mean differences and standard deviations between the control and intervention group for future experiments. Examined using planned comparison dependent t-tests to compare the changes pre- and post-12-weeks.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Ostensibly healthy men and women Subgroup study (chronic pain)
- Satisfies diagnostic criteria for fibromyalgia according to the Widespread Pain Index - Symptom Severity (WPI-SS) scale with the following three conditions being met:
- Widespread pain index (WPI) ≥7 and symptom severity (SS) scale score ≥5 or WPI 3-6 and SS scale score ≥9.
- Symptoms have been present at a similar level for at least 3 months.
- The patient does not have a disorder that would otherwise explain the pain.
Exclusion criteria
- No history of drug or alcohol dependency.
- Must be current non-smokers, and are required to have a history of less than 5 pack years of smoking.
- No history of working irregular day and night hours, regular night work, or rotating shift work for the 1 year prior to the study. In addition to this, individuals must not have traveled across more than 1 time zone during the 3 months prior to the study.
- Chronobiologic and sleep disorders.
- Diseases of the cardiovascular system.
- Hypertension. Individuals will be allowed to be normotensive (resting systolic blood pressure of \<140/90 mmHg, measured on more than one occasion) or uncomplicated stage 1 hypertension (systolic BP between 140 and 159 mmHg or a diastolic BP between 90 and 99 mmHg).
- Disorders of the respiratory system.
- Pre-diabetes/Diabetes. For participants who have self-reported pre-diabetes/diabetes.
- Disorders of the kidney and urinary tract.
- Infectious diseases.
- Disorders of the gastrointestinal system.
- Disorders of the immune system.
- Disorders of the hematopoietic system.
- Neoplastic diseases.
- Endocrine and metabolic diseases.
- Neurologic disorders.
- Must not be participating in another research study that would influence their safe participation in the study.
Where
- Portland, Oregon
Collaborators
Medical Research Foundation, Oregon
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Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Nov 10, 2025 · Source of record for eligibility and locations