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NCT06777329: VIVALDI 3
A Comparison Study Between 10 Days of Dry Immersion Versus 10 Days of Head-down Bedrest on 20 Healthy Male Volunteers
NA trial testing 10 days of dry immersion in Weightlessness Simulation in 20 participants. Completed in 23 April 2025.
23 April 2025
Quick facts
| Lead sponsor | Centre National d'Etudes Spatiales |
|---|---|
| Phase | NA |
| Status | Completed |
| Study type | INTERVENTIONAL |
| Allocation | randomized |
| Design | parallel |
| Masking | none |
| Primary purpose | basic science |
| Enrollment | 20 |
| Start date | 9 December 2024 |
| Primary completion | 23 April 2025 |
| Estimated completion | 23 April 2025 |
| Sites | 1 location across France |
Drugs / interventions tested
- 10 days of dry immersion
- 10 days of Head Down Bed Rest
Conditions studied
- Weightlessness Simulation — all drugs for Weightlessness Simulation →
Sponsor
Centre National d'Etudes Spatiales — full company profile →
Who can join
Adults 20 to 40, male only, with Weightlessness Simulation. Patients with the condition only — healthy volunteers not accepted.
Sponsor's own 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. Different methods are used to simulate weightlessness on Earth, including cellular models, animal models using hind-limb unloading, or on humans with unilateral lower limb suspension. However, two approaches, -6° head-down bed rest (HDBR) and dry immersion (DI) have provided possibilities for long-term exposures with findings closest to those seen with a weightless state. They produce changes in body composition (including body fluid redistribution), cardiovascular and skeletal muscle characteristics that resemble the effects of microgravity. The common physiological denominator is the combination of a cephalad shift of body fluids and reduced physical activity. Being similar in their effects on the human body, these models, however, differ in their specifics and acting factors. The Head-down Bedrest (HDBR) model has been widely used for this purpose and is considered one of the references for reproducing the physiological effects of weightlessness on Earth. During HDBR, subjects are lying down with an angle of -6° between the feet and head, on their side, their back or their front, but must keep one shoulder in contact with the mattress. All daily activities and tests are performed in this position. One of the advantages of the HDBR model is that it has now been used in a great number of studies internationally, and its effects have long been described and compared with those of microgravity and spaceflight. Long-term bedrest is the gold-standard method for studying the effects of weightlessness and to test countermeasures. 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 present study is to compare the physiological adaptations to10 days of dry immersion versus 10 days of head-down bedrest in 20 healthy male subjects. A set of measurements will assess the changes in the cardiovascular, neuro-ophthalmological, hematological, metabolic, sensorimotor, immune, muscle and bone systems as a result of both models. The most likely outcome of this study will not be to show a clear superiority of one model over the other. Rather, we expect to show differences in kinetics and intensity of adaptations, that should vary from one system to another. This will help future researchers choose the best model depending on the system they are investigating and the rapidity or intensity of the effect they are exploring. The two models, instead of competing with one another, are probably complementary.
Publications & conference data
No peer-reviewed publications indexed yet for this trial. Completed trials usually publish results within 12-18 months.
Verify or expand the search:
- PubMed search for NCT06777329
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Related trials
Other Centre National d'Etudes Spatiales trials
Trials by the same sponsor.
- NCT07499167 — BRAHMS: Bed Rest And HypoMetabolism Study · NA · recruiting
- NCT07278245 — Effects of Active Upper-Limb Exoskeleton Training in Simulated Hyper-Gravity on Fine Motor Performance, Brain-Muscle Con · NA · completed
- NCT06544213 — A 60 Days Head Down Tilt Bedrest With Artificial Gravity and Cycling Exercise on 24 Healthy Male (BRACE) · NA · active not recruiting
- NCT05493176 — A 5-day Dry Immersion Study on 20 Healthy Male Volunteers · NA · completed
- NCT05043974 — Integrative Study of Physiological Changes Induced by a 5-Day Dry Immersion on 20 Healthy Female Volunteers (DI5-Women) · NA · completed
Verify against primary sources
- ClinicalTrials.gov — authoritative US registry record
- WHO ICTRP — international registry index
- EU Clinical Trials Register
- Sponsor press releases (Google)
- Trial protocol + status: ClinicalTrials.gov NCT06777329 (US National Library of Medicine, public domain)
- Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
- Sponsor: as reported to ClinicalTrials.gov by Centre National d'Etudes Spatiales
- Last refreshed: 6 May 2025
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