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Circadian Rhythms and Time Perception in Healthy Adults During Constant Wakefulness

NCT07294781 · Status: RECRUITING · Phase: NA · Type: INTERVENTIONAL · Enrollment: 30

Last updated 2025-12-22

No results posted yet for this study

Summary

This study examines how the internal body clock (circadian rhythms) influences the way healthy adults experience time, think, and feel when they stay awake for an extended period. Participants will spend about 36 hours in a controlled sleep laboratory while remaining awake the entire time. Light, posture, food intake, and activity are kept as constant as possible (a "constant routine") so that changes over time mainly reflect the body's internal clock and increasing sleepiness, rather than changes in the environment. Every two hours, participants complete a brief test battery that includes ratings of sleepiness and mood, a reaction-time task, and short tasks that assess how fast or slow time seems to pass, how accurately they can estimate time intervals, how they respond to simple decisions, and how they judge colours. Saliva samples are collected repeatedly to measure melatonin, a hormone that indicates circadian phase. By comparing changes in behaviour, perception, and melatonin levels across the 36-hour wake period, the study aims to identify when during the circadian cycle people are most vulnerable to distortions in time perception and reduced alertness. The findings may help improve scheduling of shift work and other activities that require sustained wakefulness.

Conditions

  • Sleep Deprivation
  • Circadian Rhythm
  • Healthy Volunteers
  • Time Perception

Interventions

BEHAVIORAL

Constant Routine Wakefulness

Behavioral intervention consisting of approximately 36 hours of continuous wakefulness under constant-routine conditions. Environmental factors (light level, temperature, noise) are held as constant as feasible; posture and activity are standardised; and participants receive small, isocaloric snacks at regular intervals. A repeated cognitive and perceptual test battery is administered every two hours to assess time perception, vigilance, mood, and related functions across the circadian cycle.

Sponsors & Collaborators

  • Independent Research Fund Denmark

    collaborator INDUSTRY

  • University of Aarhus

    lead OTHER

Study Design

Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
23 Years
Max Age
45 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2025-12-05
Primary Completion
2027-12-30
Completion
2027-12-30

Countries

  • Denmark

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07294781 on ClinicalTrials.gov