Physiological StressDEEPTIMENCT05603780
DEEPTIME: Human Adaptation in Time Underground Isolation
A study testing exploratory protocol in people with Physiological Stress and Cognitive Dysfunction, run by University Hospital, Caen at 1 site in France.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 25 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Physiological Stress, Cognitive Dysfunction, Sleep
- What is being tested?
- exploratory protocol
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 15 participants
- Where
- 1 siteFrance
- Study dates
- 11 Mar 2021to 11 Mar 2022
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- Being pregnant Minor, under guardianship or curatorship
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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.
Read the 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.
- Conditions
- Physiological Stress, Cognitive Dysfunction, Sleep
- Being tested
- exploratory protocol
- Keywords
- Cognition, exploration, mission, endogenous biological clock, circadian rhythm, adaptation, temporal isolation, free-running, group influence, sleep, temporal anomie
- Medical subject headings
- Cognitive Dysfunction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
exploratory protocolBehavioural
physiological and cognitive evaluations
| Study group | Role | What they receive |
|---|---|---|
| group 1 | Other | one cohort Receives: Behavioral: exploratory protocol |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time
- Evaluation of time perception perceived by subjects (minute and days) every 10 days up to 40 days
Measured: every ten days up to 40 days
chronobiology
-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
Measured: every 5 days up to 40 days
Human Factors: ethological measurments with video 24/24, actimetric circadian rythms
- 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
Measured: all along the cavern experiment for 40 days
Physiology
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.
Measured: every ten days up to 40 days
Cognition, Emotion and personnality
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)
Measured: every ten to 15 days up to 40 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Nov 2022
- Study start11 Mar 2021
- Primary completion11 Sep 2021
- Study completion11 Mar 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Physiological StressStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- Follow-up of one group of healthy participant to 40days in a contraint underground environment
- Masking
- None (open label)
- Enrolment
- 15 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Caen
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- stephane besnard, MD, Principal investigator, CaenHU
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05603780
- Sponsor's protocol ID
- 2021-A00747-37
- Other IDs
- 27/21_2
- Acronym
- DEEPTIME
- Status last verified
- Aug 2022
- First submitted
- 1 Dec 2021
- Last updated
- 2 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Arbeille P, Zuj KA, Besnard S, Mauvieux B, Hingrand C, Delaunay PL, Hughson RL, Clot C. Ultrasound assessments of organs and blood vessels before and after 40 days isolation in a cavern (deep time experiment 2021). Front Physiol. 2023 Apr 24;14:1174565. doi: 10.3389/fphys.2023.1174565. eCollection 2023.
PubMed 37168224
Study at a glance
From the registry record, last updated by the sponsor on 2 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cognitive, Emotional, Physiological, Chronobiological and Genetic Effects of a Time Underground Isolation
- ClinicalTrials.gov ID
- NCT05603780
- Acronym / sponsor ID
- DEEPTIME / 2021-A00747-37
- Conditions
- Physiological Stress, Cognitive Dysfunction, Sleep
- Keywords
- Cognition, exploration, mission, endogenous biological clock, circadian rhythm, adaptation, temporal isolation, free-running
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 15 participants (actual)
- Lead sponsor
- University Hospital, CaenUniversity, hospital or other
- Study start
- 11 Mar 2021 (actual)
- Primary completion
- 11 Sep 2021 (actual)
- Study completion
- 11 Mar 2022 (actual)
- First posted
- 3 Nov 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Follow-up of one group of healthy participant to 40days in a contraint underground environment
| Arm | Type | Receives |
|---|---|---|
| group 1 | Other | Behavioral: exploratory protocolone cohort |
Who may qualify
- Ages
- 25 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- 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
Key exclusion criteria (1 listed)
- Being pregnant Minor, under guardianship or curatorship
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| exploratory protocolphysiological and cognitive evaluations | Behavioural | group 1 |
Primary outcome
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
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
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
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.
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)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Apr 2026.
- Results publication: PubMed 37168224Arbeille P, Zuj KA, Besnard S, Mauvieux B, Hingrand C, Delaunay PL, Hughson RL, Clot C. Ultrasound assessments of organs and blood vessels before and after 40 days isolation in a cavern (deep time experiment 2021). Front Physiol. 2023 Apr 24;14:1174565. doi: 10.3389/fphys.2023.1174565. eCollection 2023.
- website of the scientific expeditionLink provided by the sponsor.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
stephane besnard, MD principal investigator
CaenHU
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing exploratory protocol in people with Physiological Stress and Cognitive Dysfunction, run by University Hospital, Caen at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 2 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time (time frame: every ten days up to 40 days). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05603780, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Apr 2026.