Nighttime Synchrony of Your Nutrition and Circadian Health (N-Sync)

Nighttime Synchrony of Your Nutrition and Circadian Health: The N-Sync Study

Sleep is an important factor for overall health. This study will see how different light exposure patterns and food intake impact a person's metabolism (how the body breaks down food) when sleeping is reduced.

Participants will attend 6 to 8 in-person visits to the study clinic, including three overnight stays. People will complete surveys and medical tests. The study will last about 4 to 6 months.

Study Overview

• Status: Recruiting
• Conditions: Sleep; Sleep Deprivation; Circadian Rhythm; Light Exposure; Insufficient Sleep; Sleep Hygiene; Circadian Dysregulation; Metabolism Changes; Lifestyle Factors; Sleep Hygiene, Inadequate; Circadian Misalignment
• Intervention / Treatment: Behavioral: Central Clock Misalignment; Behavioral: Peripheral Misalignment

Detailed Description

This study is a randomized in-lab, cross-over trial. Each participant will complete all three arms in either condition order #1 (A-B-C) or order #2 (A-C-B). Each arm will consist of 5 nights of experimental sleep restriction followed by a constant routine protocol for assessment of 24-h rhythms. Sleep restriction in the three arms will occur under the following conditions: (A-control condition) Sleep Restriction with Central and Peripheral Alignment; (B) Sleep Restriction with Central Clock Misalignment; and (C) Sleep Restriction with Peripheral Misalignment. Prior to enrollment participants will complete a comprehensive medical history and clinical overnight sleep disorders screening. Baseline consists of a ~2-week ambulatory real-world monitoring segment that will occur immediately prior to each in-lab sleep restriction condition. Following the 5 days of sleep restriction in each arm, participants will complete an intravenous glucose tolerance test to analyze insulin sensitivity, prior to completing the constant routine.

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Victoria Miranda, MS; Phone Number: 385-309-0551; Email: SleepStudyParticipant@utah.edu
• Study Contact Backup: Name: Grace Zimmerman, PhD; Phone Number: 385-309-0551; Email: SleepStudyParticipant@utah.edu

Study Locations

• United States
  • Utah
    • Salt Lake City, Utah, United States, 84112
      • Recruiting
      • College of Health Research Complex - University of Utah, Salt Lake City 84112
      • Contact: Christopher Depner, PhD; Phone Number: 8015812275; Email: sleepstudyparticipant@utah.edu
      • Principal Investigator: Christopher Depner, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Age: 18-35 years old; equal numbers of men and women
2. Body Mass Index (BMI): 18.5-24.9 kg/m2
3. Sleep Habits: habitual self-reported average total sleep time (TST) 7-9 hours per night for prior 6 months

Exclusion Criteria:

1. Clinically diagnosed sleep disorder or apnea hypopnea index (AHI) ≥5
2. Evidence of significant organ system dysfunction or disease (e.g., heart disease, diabetes)
3. Fasting plasma glucose ≥100 mg/dL
4. Major psychiatric illness (e.g., major depressive disorder)
5. Cancer that has been in remission less than 5 years
6. History of shift-work in prior year
7. Weight change >5% of body weight over prior six months
8. Currently following a weight-loss program
9. Menopause
10. Pregnant/nursing
11. Greater than 5-day variation in menstrual cycle length month-to-month
12. Currently smoking
13. Alcohol intake >14 drinks/week or >3 drinks/day.
14. Use of prescription medications (except oral contraceptives) within one month prior to or during in-lab visits.
15. Consumption of illegal drugs or >500mg per day of caffeine.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Sleep Restriction with Central and Peripheral Alignment; (Arm "A")-Control condition with central and peripheral aligned circadian rhythms
Experimental: Sleep Restriction with Central Clock Misalignment; (Arm "B")-Misalignment of the central clock by nighttime electrical light exposure and dim-light in morning hours.	Behavioral: Central Clock Misalignment; Light exposure will be dimmed during the first 4 hours of scheduled wakefulness, with bright light exposure during the nighttime hours of extended wakefulness.
Experimental: Sleep Restriction with Peripheral Misalignment; (Arm "C")-Misalignment of peripheral oscillators by shifting the majority of food intake to the nighttime hours.	Behavioral: Peripheral Misalignment; Most daily calories will be given later in the day to shift eating patterns toward the nighttime hours.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin Sensitivity	Insulin sensitivity will be measured by intravenous glucose tolerance tests.	Immediately following the 5-day sleep restriction segment
Internal Circadian Misalignment (Uridine and Isobutyryl-L-carnitine)	Phase angle between DLMO and acrophase of uridine and isobutyryl-L-carnitine during constant routine.	During the constant routine, following the 5-day sleep restriction segment

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Timing of DLMO and DLMOff	The phase angle between dim-light melatonin offset (DLMOff) scheduled waketime using hourly saliva samples collected during a constant routine.	During the constant routine, following the 5-day sleep restriction segment
Hunger and Satiety Visual Analog Scales	Self-reported ratings of hunger, satiety, and prospective food intake will be quantified by 100mm visual analog scales ranging from 0 to 100. For each scale, 0 represents low hunger, satiety, or prospective food intake, with 100 representing the highest hunger, satiety, or prospective food intake.	During the constant routine, following the 5-day sleep restriction segment

Collaborators and Investigators

• Sponsor: University of Utah
• Investigators: Principal Investigator: Christopher Depner, PhD, University of Utah

Study record dates

Study Major Dates

• Study Start (Actual): December 19, 2025
• Primary Completion (Estimated): May 31, 2030
• Study Completion (Estimated): May 31, 2031

Study Registration Dates

• First Submitted: December 11, 2025
• First Submitted That Met QC Criteria: December 28, 2025
• First Posted (Actual): January 9, 2026

Study Record Updates

• Last Update Posted (Actual): January 22, 2026
• Last Update Submitted That Met QC Criteria: January 20, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Sleep; Food Intake; Circadian Rhythm; Metabolism; Sleep Hygiene; Lifestyle Factors; Light Exposure
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Sleep Wake Disorders; Dyssomnias; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Health Behavior; Sleep Deprivation; Chronobiology Disorders; Sleep Hygiene
• Other Study ID Numbers: 185590

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No