DEEPTIME: Human Adaptation in Time Underground Isolation (DEEPTIME)

March 30, 2026 updated by: University Hospital, Caen

Cognitive, Emotional, Physiological, Chronobiological and Genetic Effects of a Time Underground Isolation

The objectives of this scientific expedition are: a/ Evaluation of temporal cognitive perception and collective synchronization in a temporally anomalous universe (underground environment), b/ Influence of group living on the endogenous circadian rhythmicity of the central biological clock and peripheral clocks in a "free-running" situation (absence of light/natural darkness), c/Evaluation of cognitive and physiological performance in response to exposure to an extreme environment in a natural underground cavity (cave) without access to a time indicator for 40 days, d/Correlation of cognitive, behavioral, psychological, social, neurophysiological and physiological parameters, e/ Determination of adaptation or maladaptation criteria (biological, genetic, physiological, neurophysiological, psychological and cognitive) in an isolation environment (underground) f/ Study of the evolution of collective organization, decision making and leadership in an extreme isolation and management situation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This exceptional period has shown a significant desynchronization and loss of notion of time in a large number of people as well as important questions about human abilities to live in confined conditions. It is partly for this reason, but also to answer more fundamental questions on the perception of time that the extraordinary research expedition Deep Time was conceived: 40 days underground to know the links of our brain to time and synchronization within a group. A fundamental need for our future. This scientific expedition will take place entirely in France to ensure the feasibility and safety of the subjects and experimenters, under the direction of Christian Clot and the Institute of Human Adaptation, placed under the high patronage of the Ministry of Education, Research and Innovation.

The project addresses the fundamental question of human adaptation to the physical environment and the crucial role of the brain's neuroplasticity properties.

The present "Deep-Time" protocol naturally echoes the "out-of-time" isolation experiments conducted by the speleologist Michel Siffre starting in 1962 and its various components in the years that followed.

These "out of time" experiments led to certain conclusions. As curious as it may seem, in the absence of the time givers (synchronizers or Zeitgebers in German) that are the social rhythms and the day-night alternations, the spontaneous rhythm would settle on a rhythm of about 25 hours.

However, these experiments remained limited to isolated individuals, in conditions of spatial unity (no displacement outside of the work camps), leaving a whole field of research and questioning that the year 2021 has strongly emphasized.

The objectives of this scientific expedition are: a/ Evaluation of temporal cognitive perception and collective synchronization in a temporally anomalous universe (underground environment), b/ Influence of group living on the endogenous circadian rhythmicity of the central biological clock and peripheral clocks in a "free-running" situation (absence of light/natural darkness), c/Evaluation of cognitive and physiological performance in response to exposure to an extreme environment in a natural underground cavity (cave) without access to a time indicator for 40 days, d/Correlation of cognitive, behavioral, psychological, social, neurophysiological and physiological parameters, e/ Determination of adaptation or maladaptation criteria (biological, genetic, physiological, neurophysiological, psychological and cognitive) in an isolation environment (underground) f/ Study of the evolution of collective organization, decision making and leadership in an extreme isolation and management situation.

Study Type

Interventional

Enrollment (Actual)

15

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • France
      • Caen, France
        • CHU Caen

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

25 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

Strictly right-handed Good health without any medical and psychiatric diseases No contraindications to MRI French or European nationality Not to be included in another biomedical protocol

Exclusion Criteria:

Being pregnant Minor, under guardianship or curatorship

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: group 1
one cohort
Behavioral: exploratory protocol
physiological and cognitive evaluations

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time
Time Frame: every ten days up to 40 days
- Evaluation of time perception perceived by subjects (minute and days) every 10 days up to 40 days
every ten days up to 40 days
chronobiology
Time Frame: every 5 days up to 40 days
-Influence of group living on the endogenous circadian rhythmicity of the central biological clock and peripheral clocks in a "free-running" situation (absence of light / natural darkness): measurments of body core temperature, cortisol and melatonine salivary concentration circadian rythms
every 5 days up to 40 days
Human Factors: ethological measurments with video 24/24, actimetric circadian rythms
Time Frame: all along the cavern experiment for 40 days
- Evaluation of the capacity of a group to find a synchronicity and a way of life in a new context, extreme in its environmental and temporal dimensions and out of the initial competences of each group member. Measurments of social interaction, comparison of actimetric circadien rythm
all along the cavern experiment for 40 days
Physiology
Time Frame: every ten days up to 40 days
Physiological parameters (HRV, lean and fat mass by impedancemtry, weight in kg, core body temperature) in response to exposure to an extreme environment in a natural underground cave for 40 days.
every ten days up to 40 days
Cognition, Emotion and personnality
Time Frame: every ten to 15 days up to 40 days

Evaluation of cognitive (taking decision, emotion, spatial cognition) through differents paradigms displayed on screen of Headset in 2D and 3D virtual reality.

Mesurements of time reaction, risk score, number of strategy or procedural errors, time to achieve the tasks.

Questionnaires (STAI, POMS, big five inventory, IP9)
every ten to 15 days up to 40 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Hospital, Caen

Investigators

  • Principal Investigator: stephane besnard, MD, CaenHU

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 11, 2021

Primary Completion (Actual)

September 11, 2021

Study Completion (Actual)

March 11, 2022

Study Registration Dates

First Submitted

December 1, 2021

First Submitted That Met QC Criteria

October 27, 2022

First Posted (Actual)

November 3, 2022

Study Record Updates

Last Update Posted (Actual)

April 2, 2026

Last Update Submitted That Met QC Criteria

March 30, 2026

Last Verified

August 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2021-A00747-37
  • 27/21_2 (Other Identifier: Ethical Committee)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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