An observational study in Cold Exposure, Hypothermia, Thermal Insulation, Immersion Suits, Submarine Evacuation, sponsored by Medical Corps, Israel Defense Force. Completed at 1 site in Israel. Open to male participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-05-28.
Sponsored by Medical Corps, Israel Defense Force · Observational
This study evaluated the thermal and functional performance of full-body versus half-body Submarine Escape Immersion Equipment (SEIE) suits during cold water immersion (\~16.5°C) and raft sitting. Twenty submariners were divided into two groups.
This study investigates the performance of full-body versus half-body Submarine Escape Immersion Equipment (SEIE) suits under conditions simulating submarine emergencies in cold water (\~16.5°C). In such scenarios, rapid evacuation and prolonged exposure to cold water pose significant risks of hypothermia and impaired physical function. The aim was to assess and compare the thermal insulation and motor performance effects of both suit designs during water immersion and raft sitting.
Twenty healthy active-duty submariners (age 22 ± 1 years) participated, divided evenly into two groups (full suit vs. half suit). Core temperature was monitored using ingestible sensors, and subjective cold sensation was assessed regularly throughout immersion and raft sitting. Additional outcome measures included fine motor dexterity (assembling shackles) and handgrip strength, recorded before and after exposure.
The experimental protocol involved one session per participant. Anthropometric data were collected, and subjects underwent a controlled immersion and raft sitting protocol using calibrated thermal equipment. Motor function tasks were standardized and repeated to control for learning effects. Statistical analysis included non-parametric repeated measures tests with appropriate corrections for multiple comparisons.
449 studies on the registry are indexed under Hypothermia; 54 are open to participants now.
This study's enrollment of 20 is below the median of 95 across 106 observational studies indexed under Hypothermia.
Browse Hypothermia studies →Medical Corps, Israel Defense Force is the lead sponsor of 33 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The study population consists of healthy, active-duty male submariners from the Israeli Navy, aged 20 to 25 years. All participants were volunteers with no prior acclimatization to cold water or cold environments. Each participant underwent a medical screening by a qualified physician to confirm eligibility and provided written informed consent prior to participation. The cohort was selected to represent operationally relevant individuals likely to utilize Submarine Escape Immersion Equipment (SEIE) suits in real-world scenarios.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Healthy active-duty submariners
Male participants aged 20-25 years
No history of cardiovascular, respiratory, or neurological disorders
Not acclimatized to cold environments or cold water exposure
Provided written
Medically cleared for cold water immersion by a physician prior to participation -
Exclusion Criteria:
History of cardiovascular, respiratory, metabolic, neurological, or musculoskeletal disorders
Regular exposure to cold environments or cold water (cold-acclimatized individuals)
Use of medications that could affect thermoregulation or neuromuscular function
Any skin conditions that may be aggravated by cold water immersion
Inability to provide
Failure to pass pre-exposure medical examination by a study physician
-
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants wearing full-body Submarine Escape Immersion Equipment (SEIE) suits
Device: Submariner suit
Participants wearing half-body Submarine Escape Immersion Equipment (SEIE) suits
Device: Submariner suit
Participants wearing full-body Submarine Escape Immersion Equipment (SEIE) suits
Core temperature
Core temp. measured with telemetric pills
Time frame: two hours
Subjective cold sensation -
Assessed using a standardized cold discomfort scale during immersion and raft sitting.
Time frame: two hours
Plan to share: No — The raw, de-identified data collected during the study will be made available upon reasonable request. The dataset contains no personally identifiable information and includes only aggregated physiological and performance measurements. Data will be shared for academic, scientific, or regulatory purposes following review and approval by the principal investigator. Requests can be directed to the corresponding author.
No publications or documents are linked to this record.
This study is completed, as verified in May 2025. You cannot join it, but the record below documents what was studied.
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Medical Corps, Israel Defense Force