WeightlessnessVivalDINCT05043974
Integrative Study of Physiological Changes Induced by a 5-Day Dry Immersion on 20 Healthy Female Volunteers (DI5-Women)
A study testing Dry immersion in people with Weightlessness and Weightlessness; Adverse Effect, run by Centre National d'Etudes Spatiales at 1 site in France.
Trial summary
Dry immersion (DI) is a ground-based model of prolonged conditions of simulated microgravity. Dry immersion involves immersing the subject in water covered with an elastic waterproof fabric. As a result, the immersed subject, who is freely suspended in the water mass, remains dry. Read more about this study
- Who is it for?
- Ages 20 to 40 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Weightlessness, Weightlessness; Adverse Effect
- What is being tested?
- Dry immersion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteFrance
- Study dates
- 24 Aug 2021to 10 Dec 2021
- 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 20 to 40 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy female volunteer (see below the description of medical tests and laboratory analysis performed at the selection visit),
- Age 20 to 40,
- No overweight nor excessive thinness with BMI (weight Kg/ height m2) between 20 and 26,
- Height between 158cm and 180 cm,
- Regular menstrual cycles and cycles lasting between 20 and 35 days,
- Without oestroprogestative contraception (i.e., oral progestative contraception, IUDs, implants or absence of contraception are allowed),
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- Certified as healthy by a comprehensive clinical assessment (detailed medical history and complete physical examination): in particular, free from any chronic disease or any acute infectious disease or cardiovascular, neurological, ENT (especially orthostatic hypotension and vestibular disorders), orthopaedic or musculoskeletal disorders,
- Fitness level assessment:
- if age < 35 years: 35 ml/min./kg < VO2max < 55 ml/min./kg,
- if age > 35 years: 30 ml/min./kg < VO2max < 55 ml/min./kg,
- Non active smokers,
- No alcohol, or drug addiction, and no medical treatment (with the exception of the aforementioned accepted means of contraception),
- Covered by a Health Insurance System,
- Having signed the informed consent,
- Free from any engagement during the study.
Who cannot join
- Any history or presence of clinically relevant cardiovascular, neurological or ENT (especially orthostatic hypotension and vestibular disorders), any chronic disease; any acute infectious disease, in particular,
- Symptomatic orthostatic hypotension whatever the decrease in blood pressure,
- Asymptomatic postural hypotension defined by a decrease in SBP equal to or greater than 20 mmHg within 3 minutes when changing from the supine to the standing position,
- Cardiac rhythm disorders,
- Hypertension,
- Chronic back pains,
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- Vertebral fracture, scoliosis or herniated disc,
- Glaucoma,
- Self-reported hearing problems,
- History of migraines,
- History of hiatus hernia or gastro-esophageal reflux,
- History of thyroid dysfunction, renal stones, diabetes,
- History of head trauma,
- Abnormal result for lower limbs echo-doppler,
- History of genetic muscle and bone diseases of any kind,
- Past records of thrombophlebitis, family history of thrombosis or positive response in thrombosis screening procedure (anti thrombin III, S-protein, C-protein, factor V Leiden mutation and the mutation 20210 of the prothrombin gene),
- Women who have stopped breastfeeding within 2 months before the start of the study,
- Women who have undergone an abortion within 3 months before the start of the study,
- Irregular menstrual cycles or cycles lasting less than 20 days or more than 35 days,
- Oestroprogestative contraception,
- Recent implementation or change in hormonal contraceptive (in the last 6 months),
- Bone mineral density: T-score ≤ -1.5,
- Poor tolerance to blood sampling,
- Having given whole blood (more than 8ml/kg) in a period of 8 weeks or less before the start of the experiment, or having given whole blood more than 3 times in the past year,
- Significant history of allergy, especially no dermatological allergy,
- History of food allergy,
- Significant anomaly detected in the biological analysis,
- Positive reaction to any of the following tests: HVA IgM (hepatitis A), HBs antigen (hepatitis B), anti-HVC antibodies (hepatitis C), anti-HIV1+2 antibodies,
- Vegetarian or vegan,
- Refusal to give permission to contact her general practitioner,
- Subject who, in the judgment of the investigator, is likely to be non-compliant during the study, or unable to cooperate because of a language problem or poor mental development,
- Subject already participating or in the exclusion period of a clinical research,
- Subject who has received more than 4500 Euros within 12 months for being a research subject,
- Subject who cannot be contacted in case of emergency,
- MRI contraindications
- History or active claustrophobia,
- Osteosynthesis material, presence of metallic implants or any other contra-indication for MRI,
- Allergy to Gadolinium.
- Vulnerable persons according to law "Code de la Santé Publique" (L1121-5 to L1121-8) :
- Pregnant women (urine pregnancy test performed at the selection visit and on the day of arrival in the facility),
- Women during childbirth and breastfeeding mothers,
- Persons deprived of their liberty by an administrative or judicial decision,
- Persons under involuntary psychiatric care,
- Persons admitted in a health or social establishment for purposes other than research,
- Minors,
- Adults subject to legal protection (subject under guardianship or trusteeship) or unable to express their consent.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Integrative Study of Physiological Changes Induced by a 5-Day Dry Immersion, Used as a Ground-based Model to Mimic Weightlessness: a Pilot Study on 20 Healthy Female Volunteers (DI5-Women Study)
Dry immersion (DI) is a ground-based model of prolonged conditions of simulated microgravity. Dry immersion involves immersing the subject in water covered with an elastic waterproof fabric. As a result, the immersed subject, who is freely suspended in the water mass, remains dry. Within a relatively short duration, the model can faithfully reproduce most physiological effects of actual microgravity, including centralization of body fluids, support unloading, and hypokinesia.
The objective of the study is to evaluate the physiological changes induced by 5 days of dry immersion in the female organism. The main physiological systems will be explored before, during and after the 5 days of immersion through a battery of specific tests and measurements. The results will be analyzed by scientists specializing in each field in order to better understand the dry immersion model, to compare its effects with those of the bedrest model and those of spaceflight. The clinical (adverse effects, comfort of subjects) and operational aspects are also part of the secondary objectives of the study.
Read the detailed description
The space agencies are actively engaged in studying the physiological adaptation to space environment through studies on board the International Space Station (ISS) but also on the ground. Ground-based experiments simulating the effects of weightlessness are used to better understand the mechanisms of physiological adaptation, design and validate the countermeasures. Dry immersion (DI) is a ground-based model of prolonged conditions of simulated microgravity, which has been mainly used in Russia. The past years however, the model has been implemented as well in Europe and expertise in conducting DI studies has been gained in particular in France where a few DI studies have been conducted in the MEDES Space Clinic in Toulouse for CNES (French Space Agency). Dry immersion involves immersing the subject in water covered with an elastic waterproof fabric. As a result, the immersed subject, who is freely suspended in the water mass, remains dry. Within a relatively short duration, the model can faithfully reproduce most physiological effects of actual microgravity, including centralization of body fluids, support unloading, and hypokinesia. Furthermore, physiological changes have been reported in the neuromuscular, skeletal and sensorimotor systems, in fluid electrolyte regulation, in the cardiovascular system, metabolism, blood and immunity, respiration, and thermoregulation. Dry immersion provides a unique opportunity to study the physiological effects of the lack of a supporting structure for the body (a phenomenon called 'supportlessness'). As such, dry immersion is proposed to mimic actual spaceflight in terms of the monotonous environment, posture-motion limitations, hemodynamic changes and hypokinetic effects, support unloading, and decreased proprioceptive input. Immersion studies have so far only been conducted in men and a minority of studies using the bedrest model have included women. Likewise, few studies conducted to date have investigated gender differences in the astronaut population. The small number of female astronauts may be part of the reason why scientific data are lacking to draw valid conclusions about possible gender differences. However, if women currently constitute only about 10% of astronauts, women are and will be more and more represented in crews. Women now constitute 30% of American crews and NASA (US space agency) has announced gender parity for crews on future lunar missions. It is therefore essential to study the physiological changes induced by weightlessness in women, to compare them with those observed in men and to develop efficient countermeasures for preventing them. The main physiological systems will be explored before, during and after the 5 days of immersion through a battery of specific standardized tests and measurements. The objective of the study is to evaluate the physiological changes induced by 5 days of dry immersion in the female organism. The study conditions such as patient recruitment, nutrition, data collection, data management, reporting for adverse events are standardized. The results will be analyzed by scientists specializing in each field in order to better understand the dry immersion model, to compare its effects with those of the bedrest model and those of spaceflight. The clinical (adverse effects, comfort of subjects) and operational aspects are also part of the secondary objectives of the study.
Twenty healthy female subjects will participate in the study. There is no published data on dry immersion with female participation to help calculation the sample size. Moreover, female spaceflight and bedrest data are scarce, and do not provide any insight into inter-individual variability. This prolonged DI protocol in women is conceived as a pilot, descriptive, explorative study, as well as an operational and methodological study. Power-based calculation of the number of subjects is not directly applicable for such explorative studies. However, based on effect sizes obtained with previous DI studies in men, a total of 20 subjects was deemed necessary for this study.
- Conditions
- Weightlessness, Weightlessness; Adverse Effect
- Being tested
- Dry immersion
- Keywords
- Simulated Microgravity, Weightlessness, Dry immersion, Supportlessness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dry immersionOther
Subjects are immersed up to the neck for 5 days in a specially designed bath filled with tap water.
| Study group | Role | What they receive |
|---|---|---|
| Dry immersion | Experimental | 5 days of dry-immersion. Receives: Other: Dry immersion |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in orthostatic tolerance
Orthostatic tolerance will be assessed during a Lower Body Negative Pressure test (LBNP test)
Measured: At baseline and after five days of dry immersion
Change in peak aerobic power (VO2max test)
Exercise capacity wil be assessed by graded cycling on sitting ergometer until exhaustion
Measured: At baseline and after five days of dry immersion
Change in plasma volume
Plasma volume (L) will be assessed by the CO-rebreathing method.
Measured: At baseline and after five days of dry immersion
Change in fluid shift distribution towards the cephalic region
The hemodynamic and morphologic consequences of the fluid shift on the cephalic blood vessels (jugular vein, carotid, femoral, intracranial veins) and on the left ventricle will be investigated by ultrasound.
The hormones involved in fluid distribution will be assessed in blood and urine samples
Measured: At baseline, the first day to quantify the short term effect and the fifth day of dry-immersion to quantify the long term effect of fluid shift
Change in vascular endothelium integrity
Vascular endothelium integrity will be assessed by blood parameters of vascular and endothelial integrity. Global score of endothelial state will be calculated.
Measured: At baseline and during the five days of the dry-immersion period
Change in circadian rhythms of blood pressure
Continuous 24-h recording of blood pressure will be performed by SOMNOtouch™ NIBP system designed for ambulatory continuous measurements
Measured: At baseline and during the five days of the dry-immersion period
Change in lower limb veins functions
Venous compliance of lower limbs will be assessed by plethysmography.
Measured: At baseline, after four days of dry-immersion and after one day of recovery
Change in body fluid compartments by bioelectrical impedance analysis
Extracellular, intracellular and total body water will be estimated by bioimpedance
Measured: Baseline and during five days of dry-immersion
Change in muscle strength
Muscle strength will be assessed from single leg isometric maximal voluntary contraction on the knee extensors \& flexors, the plantarflexors and dorsiflexors. The Isometric Torque will be measured in Nm. The peak of the three maximal attempts will be recorded for strength measures.
Measured: At baseline and after five days of dry-immersion
Change in muscle fatigue
Muscle fatigability will be assessed during a submaximal isometric knee extension contraction held for 30 seconds at 50% of the baseline MVC value.
Measured: At baseline and after five days of dry-immersion
Change in muscle volume at calf level
Muscle dehydration, eventual atrophy and fatty degeneration will be measured by quantitative Dixon MRI sequences at calf level
Measured: At baseline and after five days of dry-immersion
Change in contraction time
Contraction time will be assessed during a tensiomyographic test in vastus lateralis, Gastrocnemius medialis and Biceps femoris of dominant leg / arm
Measured: At baseline and after five days of dry-immersion
Change in bone metabolism
Bone metabolism in response to immobilization by dry immersion will be assessed by measuring bone biomarkers in blood samples.
Measured: At baseline, during and after 5 days of dry-immersion
Changes in cartilage metabolism
Cartilage metabolism in response to immobilization by dry immersion will be assessed by measuring cartilage biomarkers in blood and urine samples.
Measured: At baseline, during and after 5 days of dry-immersion
Change in Resting Metabolic Rate (RMR)
RMR will be measured by indirect calorimetry technique
Measured: At baseline, during and after 5 days of dry-immersion
Change in nitrogen balance
Nitrogen balance is a measure of nitrogen input minus nitrogen output. Nitrogen intake is calculated with a nutrition software. Protein oxidation measured in the 24-Hour urine collection estimates nitrogen output.
Measured: At baseline, during and after 5 days of dry-immersion
Change in Body Composition measured by DEXA
DEXA is a standard clinical technique to assess body composition
Measured: At baseline and at the end of the 5 days of dry-immersion
Change in glucose tolerance (Oral Glucose Tolerance Test)
Glucose and insulin levels will be measured at baseline (fasting) and 30, 60, 90, and 120 minutes after drinking within 5 min a water solution containing 75 g of glucose.
Measured: At baseline and after 3 days of dry-immersion (to be comparable to a previous study on men)
Change in Core temperature
Measured by electronic ingestible temperature capsules (e-Celsius Performance)
Measured: At baseline and during the 5 days of dry immersion
Change in height
Measured in supine and standing position
Measured: At baseline, during and after the 5 days of dry immersion
Change in mid cerebral artery (MCA) blood flow velocity
Transcranial Doppler measurements
Measured: Before and after the 5 days of dry immersion
Change in mood
Change in mood is assessed using the Profile of Mood States (POMS) questionnaire. (POMS).
Measured: At baseline, during and after 5 days of dry-immersion
Change in psychological affects
PANAS Questionnaire will be used to assess the intensity of positive and negative affective states
Measured: At baseline, during and after 5 days of dry-immersion
Change in psychological state: sleep quality
Pittsburgh Sleep Dairy will be used to assess sleep perceived quality
Measured: At baseline, during and after 5 days of dry-immersion
Change in psychological state: mental health
GHQ-28 Questionnaire will be used to assess psychological well-being and capture distress
Measured: At baseline, during and after 5 days of dry-immersion
Change in psychological state: coping strategies
Brief Cope Questionnaire, designed to measure effective and ineffective ways to cope with a stressful life event, will be used to assess coping strategies
Measured: At baseline, during and after 5 days of dry-immersion
Change in cerebral autoregulation
Transcranial Doppler measurements of mid cerebral artery blood flow velocity will allow to determine cerebral autoregulation
Measured: At baseline and after 5 days of dry-immersion
Change in Intra Cranial Pressure (ICP)
ICP changes will be monitored through OtoAcoustic Emissions (OAE).
Measured: At baseline, during and after 5 days of dry-immersion
Change in optic nerve sheath diameter (ONSD) considered as an indirect marker for intracranial pressure (ICP) estimation.
The optic nerve sheath diameter (ONSD) variations will be measured by echography.
Measured: At baseline, during and after 5 days of dry-immersion
Change in the optic nerve fibers thickness.
Thickness of the optic nerve fibers will be measured by Optical Coherence Tomography (OCT)
Measured: At baseline and after five days of dry-immersion
Change in intraocular pressure (IOP)
IOP measured by applanation
Measured: At baseline, during and after five days of dry-immersion
Change in visual acuity
Far and near visual acuity are tested uncorrected, or if applicable with own correction with digital acuity system.
Measured: At baseline and after five days of dry-immersion
Change in visual field
Visual field measured by standard automated perimetry
Measured: At baseline and after five days of dry-immersion
Change in the anatomical characteristics of the eye (optical biometry)
Optical biometry measured by partial coherence interferometry
Measured: At baseline and after five days of dry-immersion
Change in the central corneal thickness
Central corneal thickness on a single point on the cornea measured by Ultrasonic pachymetry
Measured: At baseline and after five days of dry-immersion
Change in the retina by non-mydriatic fundus retinography
Non-mydriatic fundus retinography allows a fundus photography to be taken and thus a color image of the papilla, retinal vessels and macula.
Measured: At baseline and after five days of dry-immersion
Change in the cornea topography
Cornea topography measured by corneal topography equipment (like Pentacam). The elevation topography according to Scheimpflug principle allows the mapping of the anterior and posterior surface of the cornea.
Measured: At baseline and after five days of dry-immersion
Change in cerebral structures and in venous circulation of the brain by MRI
Visualization of cerebral structures and intracranial venous system will be performed by MRI coupled with injection of gadolinium.
Measured: At baseline and after five days of dry-immersion
Change in walking balance
Walking balance will be assessed by Dynamic Gait Index, specific parameter is: total Score (range 0-24). Higher scores mean a better outcome.
Measured: At baseline and after five days of dry-immersion
Change in standing balance
Standing balance will be assessed by posturography eyes open and eyes closed on a platform covered with 12-cm thick medium density foam.
Measured: At baseline and after five days of dry-immersion
Change in motion sickness susceptibility
Motion Sickness Questionnaire
Measured: At baseline and after five days of dry-immersion
Change in coagulation cascade
Coagulation cascade in response to immobilization by dry immersion will be assessed by measuring coagulation parameters in blood.
Measured: At baseline, during and after 5 days of dry immersion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Sep 2021
- Study start24 Aug 2021
- Primary completion8 Dec 2021
- Study completion10 Dec 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for WeightlessnessStudies 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
- Masking
- None (open label)
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Centre National d'Etudes Spatiales
- Sponsor type
- Other government
- Collaborators
- European Space Agency
- Responsible party
- Sponsor
- Investigators
- Arnaud BECK, MD, Principal investigator, MEDES - IMPS
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05043974
- Sponsor's protocol ID
- 20-232
- Other IDs
- 2021-A00705-36
- Acronym
- VivalDI
- Status last verified
- Sep 2021
- First submitted
- 30 Jul 2021
- Last updated
- 21 Jul 2022
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Navasiolava NM, Custaud MA, Tomilovskaya ES, Larina IM, Mano T, Gauquelin-Koch G, Gharib C, Kozlovskaya IB. Long-term dry immersion: review and prospects. Eur J Appl Physiol. 2011 Jul;111(7):1235-60. doi: 10.1007/s00421-010-1750-x. Epub 2010 Dec 14.
PubMed 21161267De Abreu S, Amirova L, Murphy R, Wallace R, Twomey L, Gauquelin-Koch G, Raverot V, Larcher F, Custaud MA, Navasiolava N. Multi-System Deconditioning in 3-Day Dry Immersion without Daily Raise. Front Physiol. 2017 Oct 13;8:799. doi: 10.3389/fphys.2017.00799. eCollection 2017.
PubMed 29081752Kermorgant M, Leca F, Nasr N, Custaud MA, Geeraerts T, Czosnyka M, Arvanitis DN, Senard JM, Pavy-Le Traon A. Impacts of Simulated Weightlessness by Dry Immersion on Optic Nerve Sheath Diameter and Cerebral Autoregulation. Front Physiol. 2017 Oct 12;8:780. doi: 10.3389/fphys.2017.00780. eCollection 2017.
PubMed 29075198Linossier MT, Amirova LE, Thomas M, Normand M, Bareille MP, Gauquelin-Koch G, Beck A, Costes-Salon MC, Bonneau C, Gharib C, Custaud MA, Vico L. Effects of short-term dry immersion on bone remodeling markers, insulin and adipokines. PLoS One. 2017 Aug 14;12(8):e0182970. doi: 10.1371/journal.pone.0182970. eCollection 2017.
PubMed 28806419Moser D, Bareille MP, Ombergen AV, Hoerl M, D Amico F, Feuerecker M, Dachert C, Matzel S, Robin A, Navasiolava N, Custaud MA, Chouker A; Members of the VivalDI -study and Dry Immersion expert group. Fluid shifts are main drivers for microgravity simulation-induced immune-physiological changes: findings from the VIVALDI studies. NPJ Microgravity. 2026 Feb 16;12(1):15. doi: 10.1038/s41526-025-00555-z.
PubMed 41698943Jacob P, Robin A, Navasiolava N, Custaud MA, Ghislin S, Bareille MP, De Villemeur RB, Antunes I, Van Ombergen A, Gauquelin-Koch G, Frippiat JP. ESA VIVALDI Dry Immersion Microgravity Simulations Induce Increases in Immune Biomarkers Associated With Physical and Psychological Stress, and Sex-Specific Factors. FASEB J. 2025 Sep 15;39(17):e70993. doi: 10.1096/fj.202502198R.
PubMed 40892712Robin A, Van Ombergen A, Laurens C, Bergouignan A, Vico L, Linossier MT, Pavy-Le Traon A, Kermorgant M, Chopard A, Py G, Green DA, Tipton M, Chouker A, Denise P, Normand H, Blanc S, Simon C, Rosnet E, Larcher F, Fernandez P, de Glisezinski I, Larrouy D, Harant-Farrugia I, Antunes I, Gauquelin-Koch G, Bareille MP, Billette De Villemeur R, Custaud MA, Navasiolava N. Comprehensive assessment of physiological responses in women during the ESA dry immersion VIVALDI microgravity simulation. Nat Commun. 2023 Oct 9;14(1):6311. doi: 10.1038/s41467-023-41990-4.
PubMed 37813884
Study at a glance
From the registry record, last updated by the sponsor on 21 Jul 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Integrative Study of Physiological Changes Induced by a 5-Day Dry Immersion, Used as a Ground-based Model to Mimic Weightlessness: a Pilot Study on 20 Healthy Female Volunteers (DI5-Women Study)
- ClinicalTrials.gov ID
- NCT05043974
- Acronym / sponsor ID
- VivalDI / 20-232
- Conditions
- Weightlessness, Weightlessness; Adverse Effect
- Keywords
- Simulated Microgravity, Weightlessness, Dry immersion, Supportlessness
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Centre National d'Etudes SpatialesOther government
- Collaborators
- European Space Agency
- Study start
- 24 Aug 2021 (actual)
- Primary completion
- 8 Dec 2021 (actual)
- Study completion
- 10 Dec 2021 (actual)
- First posted
- 14 Sep 2021 (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.
Dry immersion (DI) is a ground-based model of prolonged conditions of simulated microgravity. Dry immersion involves immersing the subject in water covered with an elastic waterproof fabric. As a result, the immersed subject, who is freely suspended in the water mass, remains dry. Within a relatively short duration, the model can faithfully reproduce most physiological effects of actual microgravity, including centralization of body fluids, support unloading, and hypokinesia.
The objective of the study is to evaluate the physiological changes induced by 5 days of dry immersion in the female organism. The main physiological systems will be explored before, during and after the 5 days of immersion through a battery of specific tests and measurements. The results will be analyzed by scientists specializing in each field in order to better understand the dry immersion model, to compare its effects with those of the bedrest model and those of spaceflight. The clinical (adverse effects, comfort of subjects) and operational aspects are also part of the secondary objectives of the study.
Detailed description
The space agencies are actively engaged in studying the physiological adaptation to space environment through studies on board the International Space Station (ISS) but also on the ground. Ground-based experiments simulating the effects of weightlessness are used to better understand the mechanisms of physiological adaptation, design and validate the countermeasures. Dry immersion (DI) is a ground-based model of prolonged conditions of simulated microgravity, which has been mainly used in Russia. The past years however, the model has been implemented as well in Europe and expertise in conducting DI studies has been gained in particular in France where a few DI studies have been conducted in the MEDES Space Clinic in Toulouse for CNES (French Space Agency). Dry immersion involves immersing the subject in water covered with an elastic waterproof fabric. As a result, the immersed subject, who is freely suspended in the water mass, remains dry. Within a relatively short duration, the model can faithfully reproduce most physiological effects of actual microgravity, including centralization of body fluids, support unloading, and hypokinesia. Furthermore, physiological changes have been reported in the neuromuscular, skeletal and sensorimotor systems, in fluid electrolyte regulation, in the cardiovascular system, metabolism, blood and immunity, respiration, and thermoregulation. Dry immersion provides a unique opportunity to study the physiological effects of the lack of a supporting structure for the body (a phenomenon called 'supportlessness'). As such, dry immersion is proposed to mimic actual spaceflight in terms of the monotonous environment, posture-motion limitations, hemodynamic changes and hypokinetic effects, support unloading, and decreased proprioceptive input. Immersion studies have so far only been conducted in men and a minority of studies using the bedrest model have included women. Likewise, few studies conducted to date have investigated gender differences in the astronaut population. The small number of female astronauts may be part of the reason why scientific data are lacking to draw valid conclusions about possible gender differences. However, if women currently constitute only about 10% of astronauts, women are and will be more and more represented in crews. Women now constitute 30% of American crews and NASA (US space agency) has announced gender parity for crews on future lunar missions. It is therefore essential to study the physiological changes induced by weightlessness in women, to compare them with those observed in men and to develop efficient countermeasures for preventing them. The main physiological systems will be explored before, during and after the 5 days of immersion through a battery of specific standardized tests and measurements. The objective of the study is to evaluate the physiological changes induced by 5 days of dry immersion in the female organism. The study conditions such as patient recruitment, nutrition, data collection, data management, reporting for adverse events are standardized. The results will be analyzed by scientists specializing in each field in order to better understand the dry immersion model, to compare its effects with those of the bedrest model and those of spaceflight. The clinical (adverse effects, comfort of subjects) and operational aspects are also part of the secondary objectives of the study.
Twenty healthy female subjects will participate in the study. There is no published data on dry immersion with female participation to help calculation the sample size. Moreover, female spaceflight and bedrest data are scarce, and do not provide any insight into inter-individual variability. This prolonged DI protocol in women is conceived as a pilot, descriptive, explorative study, as well as an operational and methodological study. Power-based calculation of the number of subjects is not directly applicable for such explorative studies. However, based on effect sizes obtained with previous DI studies in men, a total of 20 subjects was deemed necessary for this study.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Dry immersion | Experimental | Other: Dry immersion5 days of dry-immersion. |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (15 listed)
- Healthy female volunteer (see below the description of medical tests and laboratory analysis performed at the selection visit),
- Age 20 to 40,
- No overweight nor excessive thinness with BMI (weight Kg/ height m2) between 20 and 26,
- Height between 158cm and 180 cm,
- Regular menstrual cycles and cycles lasting between 20 and 35 days,
Key exclusion criteria (46 listed)
- Any history or presence of clinically relevant cardiovascular, neurological or ENT (especially orthostatic hypotension and vestibular disorders), any chronic disease; any acute infectious disease, in particular,
- Symptomatic orthostatic hypotension whatever the decrease in blood pressure,
- Asymptomatic postural hypotension defined by a decrease in SBP equal to or greater than 20 mmHg within 3 minutes when changing from the supine to the standing position,
- Cardiac rhythm disorders,
- Hypertension,
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 |
|---|---|---|
| Dry immersionSubjects are immersed up to the neck for 5 days in a specially designed bath filled with tap water. | Other | Dry immersion |
Primary outcome
Change in orthostatic tolerance
Time frame: At baseline and after five days of dry immersion
Orthostatic tolerance will be assessed during a Lower Body Negative Pressure test (LBNP test)
Change in peak aerobic power (VO2max test)
Time frame: At baseline and after five days of dry immersion
Exercise capacity wil be assessed by graded cycling on sitting ergometer until exhaustion
Change in plasma volume
Time frame: At baseline and after five days of dry immersion
Plasma volume (L) will be assessed by the CO-rebreathing method.
Change in fluid shift distribution towards the cephalic region
Time frame: At baseline, the first day to quantify the short term effect and the fifth day of dry-immersion to quantify the long term effect of fluid shift
The hemodynamic and morphologic consequences of the fluid shift on the cephalic blood vessels (jugular vein, carotid, femoral, intracranial veins) and on the left ventricle will be investigated by ultrasound. The hormones involved in fluid distribution will be assessed in blood and urine samples
Change in vascular endothelium integrity
Time frame: At baseline and during the five days of the dry-immersion period
Vascular endothelium integrity will be assessed by blood parameters of vascular and endothelial integrity. Global score of endothelial state will be calculated.
Change in circadian rhythms of blood pressure
Time frame: At baseline and during the five days of the dry-immersion period
Continuous 24-h recording of blood pressure will be performed by SOMNOtouch™ NIBP system designed for ambulatory continuous measurements
Change in lower limb veins functions
Time frame: At baseline, after four days of dry-immersion and after one day of recovery
Venous compliance of lower limbs will be assessed by plethysmography.
Change in body fluid compartments by bioelectrical impedance analysis
Time frame: Baseline and during five days of dry-immersion
Extracellular, intracellular and total body water will be estimated by bioimpedance
Change in muscle strength
Time frame: At baseline and after five days of dry-immersion
Muscle strength will be assessed from single leg isometric maximal voluntary contraction on the knee extensors \& flexors, the plantarflexors and dorsiflexors. The Isometric Torque will be measured in Nm. The peak of the three maximal attempts will be recorded for strength measures.
Change in muscle fatigue
Time frame: At baseline and after five days of dry-immersion
Muscle fatigability will be assessed during a submaximal isometric knee extension contraction held for 30 seconds at 50% of the baseline MVC value.
Change in muscle volume at calf level
Time frame: At baseline and after five days of dry-immersion
Muscle dehydration, eventual atrophy and fatty degeneration will be measured by quantitative Dixon MRI sequences at calf level
Change in contraction time
Time frame: At baseline and after five days of dry-immersion
Contraction time will be assessed during a tensiomyographic test in vastus lateralis, Gastrocnemius medialis and Biceps femoris of dominant leg / arm
Change in bone metabolism
Time frame: At baseline, during and after 5 days of dry-immersion
Bone metabolism in response to immobilization by dry immersion will be assessed by measuring bone biomarkers in blood samples.
Changes in cartilage metabolism
Time frame: At baseline, during and after 5 days of dry-immersion
Cartilage metabolism in response to immobilization by dry immersion will be assessed by measuring cartilage biomarkers in blood and urine samples.
Change in Resting Metabolic Rate (RMR)
Time frame: At baseline, during and after 5 days of dry-immersion
RMR will be measured by indirect calorimetry technique
Change in nitrogen balance
Time frame: At baseline, during and after 5 days of dry-immersion
Nitrogen balance is a measure of nitrogen input minus nitrogen output. Nitrogen intake is calculated with a nutrition software. Protein oxidation measured in the 24-Hour urine collection estimates nitrogen output.
Change in Body Composition measured by DEXA
Time frame: At baseline and at the end of the 5 days of dry-immersion
DEXA is a standard clinical technique to assess body composition
Change in glucose tolerance (Oral Glucose Tolerance Test)
Time frame: At baseline and after 3 days of dry-immersion (to be comparable to a previous study on men)
Glucose and insulin levels will be measured at baseline (fasting) and 30, 60, 90, and 120 minutes after drinking within 5 min a water solution containing 75 g of glucose.
Change in Core temperature
Time frame: At baseline and during the 5 days of dry immersion
Measured by electronic ingestible temperature capsules (e-Celsius Performance)
Change in height
Time frame: At baseline, during and after the 5 days of dry immersion
Measured in supine and standing position
Change in mid cerebral artery (MCA) blood flow velocity
Time frame: Before and after the 5 days of dry immersion
Transcranial Doppler measurements
Change in mood
Time frame: At baseline, during and after 5 days of dry-immersion
Change in mood is assessed using the Profile of Mood States (POMS) questionnaire. (POMS).
Change in psychological affects
Time frame: At baseline, during and after 5 days of dry-immersion
PANAS Questionnaire will be used to assess the intensity of positive and negative affective states
Change in psychological state: sleep quality
Time frame: At baseline, during and after 5 days of dry-immersion
Pittsburgh Sleep Dairy will be used to assess sleep perceived quality
Change in psychological state: mental health
Time frame: At baseline, during and after 5 days of dry-immersion
GHQ-28 Questionnaire will be used to assess psychological well-being and capture distress
Change in psychological state: coping strategies
Time frame: At baseline, during and after 5 days of dry-immersion
Brief Cope Questionnaire, designed to measure effective and ineffective ways to cope with a stressful life event, will be used to assess coping strategies
Change in cerebral autoregulation
Time frame: At baseline and after 5 days of dry-immersion
Transcranial Doppler measurements of mid cerebral artery blood flow velocity will allow to determine cerebral autoregulation
Change in Intra Cranial Pressure (ICP)
Time frame: At baseline, during and after 5 days of dry-immersion
ICP changes will be monitored through OtoAcoustic Emissions (OAE).
Change in optic nerve sheath diameter (ONSD) considered as an indirect marker for intracranial pressure (ICP) estimation.
Time frame: At baseline, during and after 5 days of dry-immersion
The optic nerve sheath diameter (ONSD) variations will be measured by echography.
Change in the optic nerve fibers thickness.
Time frame: At baseline and after five days of dry-immersion
Thickness of the optic nerve fibers will be measured by Optical Coherence Tomography (OCT)
Change in intraocular pressure (IOP)
Time frame: At baseline, during and after five days of dry-immersion
IOP measured by applanation
Change in visual acuity
Time frame: At baseline and after five days of dry-immersion
Far and near visual acuity are tested uncorrected, or if applicable with own correction with digital acuity system.
Change in visual field
Time frame: At baseline and after five days of dry-immersion
Visual field measured by standard automated perimetry
Change in the anatomical characteristics of the eye (optical biometry)
Time frame: At baseline and after five days of dry-immersion
Optical biometry measured by partial coherence interferometry
Change in the central corneal thickness
Time frame: At baseline and after five days of dry-immersion
Central corneal thickness on a single point on the cornea measured by Ultrasonic pachymetry
Change in the retina by non-mydriatic fundus retinography
Time frame: At baseline and after five days of dry-immersion
Non-mydriatic fundus retinography allows a fundus photography to be taken and thus a color image of the papilla, retinal vessels and macula.
Change in the cornea topography
Time frame: At baseline and after five days of dry-immersion
Cornea topography measured by corneal topography equipment (like Pentacam). The elevation topography according to Scheimpflug principle allows the mapping of the anterior and posterior surface of the cornea.
Change in cerebral structures and in venous circulation of the brain by MRI
Time frame: At baseline and after five days of dry-immersion
Visualization of cerebral structures and intracranial venous system will be performed by MRI coupled with injection of gadolinium.
Change in walking balance
Time frame: At baseline and after five days of dry-immersion
Walking balance will be assessed by Dynamic Gait Index, specific parameter is: total Score (range 0-24). Higher scores mean a better outcome.
Change in standing balance
Time frame: At baseline and after five days of dry-immersion
Standing balance will be assessed by posturography eyes open and eyes closed on a platform covered with 12-cm thick medium density foam.
Change in motion sickness susceptibility
Time frame: At baseline and after five days of dry-immersion
Motion Sickness Questionnaire
Change in coagulation cascade
Time frame: At baseline, during and after 5 days of dry immersion
Coagulation cascade in response to immobilization by dry immersion will be assessed by measuring coagulation parameters in blood.
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 21 Jul 2022.
- Background: PubMed 21161267Navasiolava NM, Custaud MA, Tomilovskaya ES, Larina IM, Mano T, Gauquelin-Koch G, Gharib C, Kozlovskaya IB. Long-term dry immersion: review and prospects. Eur J Appl Physiol. 2011 Jul;111(7):1235-60. doi: 10.1007/s00421-010-1750-x. Epub 2010 Dec 14.
- Background: PubMed 29081752De Abreu S, Amirova L, Murphy R, Wallace R, Twomey L, Gauquelin-Koch G, Raverot V, Larcher F, Custaud MA, Navasiolava N. Multi-System Deconditioning in 3-Day Dry Immersion without Daily Raise. Front Physiol. 2017 Oct 13;8:799. doi: 10.3389/fphys.2017.00799. eCollection 2017.
- Background: PubMed 29075198Kermorgant M, Leca F, Nasr N, Custaud MA, Geeraerts T, Czosnyka M, Arvanitis DN, Senard JM, Pavy-Le Traon A. Impacts of Simulated Weightlessness by Dry Immersion on Optic Nerve Sheath Diameter and Cerebral Autoregulation. Front Physiol. 2017 Oct 12;8:780. doi: 10.3389/fphys.2017.00780. eCollection 2017.
- Background: PubMed 28806419Linossier MT, Amirova LE, Thomas M, Normand M, Bareille MP, Gauquelin-Koch G, Beck A, Costes-Salon MC, Bonneau C, Gharib C, Custaud MA, Vico L. Effects of short-term dry immersion on bone remodeling markers, insulin and adipokines. PLoS One. 2017 Aug 14;12(8):e0182970. doi: 10.1371/journal.pone.0182970. eCollection 2017.
- Derived from this study: PubMed 41698943Moser D, Bareille MP, Ombergen AV, Hoerl M, D Amico F, Feuerecker M, Dachert C, Matzel S, Robin A, Navasiolava N, Custaud MA, Chouker A; Members of the VivalDI -study and Dry Immersion expert group. Fluid shifts are main drivers for microgravity simulation-induced immune-physiological changes: findings from the VIVALDI studies. NPJ Microgravity. 2026 Feb 16;12(1):15. doi: 10.1038/s41526-025-00555-z.
- Derived from this study: PubMed 40892712Jacob P, Robin A, Navasiolava N, Custaud MA, Ghislin S, Bareille MP, De Villemeur RB, Antunes I, Van Ombergen A, Gauquelin-Koch G, Frippiat JP. ESA VIVALDI Dry Immersion Microgravity Simulations Induce Increases in Immune Biomarkers Associated With Physical and Psychological Stress, and Sex-Specific Factors. FASEB J. 2025 Sep 15;39(17):e70993. doi: 10.1096/fj.202502198R.
- Derived from this study: PubMed 37813884Robin A, Van Ombergen A, Laurens C, Bergouignan A, Vico L, Linossier MT, Pavy-Le Traon A, Kermorgant M, Chopard A, Py G, Green DA, Tipton M, Chouker A, Denise P, Normand H, Blanc S, Simon C, Rosnet E, Larcher F, Fernandez P, de Glisezinski I, Larrouy D, Harant-Farrugia I, Antunes I, Gauquelin-Koch G, Bareille MP, Billette De Villemeur R, Custaud MA, Navasiolava N. Comprehensive assessment of physiological responses in women during the ESA dry immersion VIVALDI microgravity simulation. Nat Commun. 2023 Oct 9;14(1):6311. doi: 10.1038/s41467-023-41990-4.
- Individual participant dataSharing planned: No
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.
Arnaud BECK, MD principal investigator
MEDES - IMPS
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Dry immersion in people with Weightlessness and Weightlessness; Adverse Effect, run by Centre National d'Etudes Spatiales 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 15 inclusion and 46 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 21 Jul 2022. 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?
Change in orthostatic tolerance (time frame: At baseline and after five days of dry immersion). The study lists 42 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 NCT05043974, which also lists 7 linked publications.
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 21 Jul 2022.