The Effect of a Continuous 1-Hour Time Delay on Circadian Rhythms

University of Aarhus

Status: Enrolling

Conditions: Time Perception; Circadian Rhythms; Sleep

Treatments: Behavioral: Fixed daily routine; Behavioral: Daily time delay

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT07317349

1-10-72-143-25

10.46540/425600108B (Other Grant/Funding Number)

Details and patient eligibility

About

The purpose of this study is to investigate whether the experience of a daily time delay can affect our internal circadian rhythm.

Enrollment: 40 estimated patients

Sex: All

Ages: 23 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria

• Healthy adults aged 23-45 years
• Part of a heterosexual, cohabiting couple willing to participate together in a five-day in-laboratory study
• Both partners meet all inclusion criteria
• Completion of at least upper-secondary education
• Maintain a regular sleep-wake schedule
• Habitual sleep timing within a normative range (non-extreme chronotype), assessed using the Morningness-Eveningness Questionnaire (MEQ) or the Munich Chronotype Questionnaire (MCTQ)
• Both partners fall within the acceptable chronotype range to ensure aligned sleep-wake patterns
• Low seasonality scores on the Seasonal Pattern Assessment Questionnaire (SPAQ)
• Free from underlying sleep or mood disorders

Exclusion Criteria

• Engages in night-shift work or maintains an irregular work or sleep schedule
• International travel involving a time-zone change of more than two hours within the past two months, or anticipated travel before study completion
• Diagnosed neurological, psychiatric, or sleep disorder (e.g., insomnia, sleep apnea, bipolar disorder)
• High risk of sleep apnea, defined as a Berlin Questionnaire score >2 (Lauritzen et al., 2018)
• Use of medications known to affect sleep, alertness, melatonin secretion, or circadian timing
• Unable or unwilling to comply with behavioral restrictions, including refraining from electronic devices displaying time cues unless clocks are removed and devices are disconnected from Wi-Fi
• Unable or unwilling to comply with consumption restrictions, including abstaining from caffeine, alcohol, and melatonin-rich foods during the study
• Extreme chronotype, defined as a habitual midsleep time outside 03:00-05:00 on the MCTQ or classification as an extreme morning or extreme evening type on the MEQ
• Daily caffeine consumption exceeding 400 mg (approximately 4-5 cups of coffee)
• Current smoker or smoking within the past six months

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Single Group Assignment

Masking: None (Open label)

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40 participants in 2 patient groups

Fixed daily routine

Experimental group

Description:

All activities occur at the same time every day. During the five days, participants will have to complete various daily tests and also be asked to provide 8 saliva samples during days 1, 3, and 5

Treatment:

Behavioral: Fixed daily routine

Daily time delay of 1 hour

Experimental group

Description:

All activities will be delayed by one hour. During the five days, participants will have to complete various daily tests and also be asked to provide 8 saliva samples during days 1, 3, and 5

Treatment:

Behavioral: Daily time delay