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

Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age23-45
SponsorUniversity of Aarhus

About this trial

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

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

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

Disqualifiers

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)

Trial design

Design model

Single group

Treatments tested in this trial

  • Fixed daily routine

    Behavioral

    All activities occur at the same time every day

  • Daily time delay

    Behavioral

    All activities will be delayed by one hour per day over a 5 day period.

Treatment groups

40 Participants
are divided into 2 treatment groups
Group A: Fixed daily routineExperimental treatment 1 intervention
Group B: Daily time delay of 1 hourExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

Phase shift in circadian rhythm markers

The primary outcome is the timing of dim light melatonin onset, a marker of circadian phase. Saliva samples will be collected at regular intervals under dim light, and the time when melatonin exceeds 3 pg/mL will be recorded for each participant. This allows measurement of circadian phase shifts across conditions.

Time frame
Comparing samples on days 1, 3, 5

Secondary outcomes

1

Psychomotor Vigilance Task (PVT) Median Reaction Time

Median reaction time (milliseconds) on a brief psychomotor vigilance task (PVT) six times each day. Participants respond as quickly as possible to visual stimuli presented at random inter-stimulus intervals. For each block, the median reaction time is computed; additional indices such as lapses (responses \> 500 ms) may be derived. Changes in PVT performance across the the 5 days are analysed in relation to circadian phase.

Time frame
Performance will be measured at regular intervals on days 1 - 5 to track changes over the course of the study.

Other outcomes

Sponsors and contacts

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University of Aarhus

Lead sponsor

Independent Research Fund Denmark

Collaborator