On board the International Space Station, crew members conduct many science experiments, including some of which they are guinea pigs! It is about better understanding the effects of space travel on the human body. These studies must be supplemented by others carried out on the ground and this is in particular what the Space Clinic* of the’MEDES Institute of Space Medicine and Physiology a Toulouse.

In the water, but dry!

There are in fact for the moment quite a few people who have gone and who are going in space in orbit (a little less than 600 different ones). Ground studies make it possible to multiply the subjects and even to accomplish experiments which are difficult, if not impossible, during missions around the Earth. A classic device called Bedrest consists of resting volunteers at an angle of 6 °, head down, which induces physiological consequences very similar to those suffered by astronauts (cardiovascular deconditioning, minimal strain on muscles and bones, etc.). Another method is proving to be very effective and it comes from Russia:dry immersion.

The idea is to immerse the volunteer in a pool so that the water pressure is exerted uniformly on the body which interprets it as a complete absence of support. But water in contact with the skin had other consequences that disrupted the study. The Moscow Institute of Medical Biological Problems (IMBP) has for years found a solution using waterproof fabric. In addition, the temperature of the water and the room is controlled. The dry immersion then reproduces the effects of weightlessness for the cardiovascular systems as well as for sensations and motor skills.
The MEDES Space Clinic adopted this model and with the European Space Agency (ESA) launched theVIVALDI study during which, from the end of September until mid-December, 20 women remain in dry immersion for 5 days. This is the first time that this process has been used on an exclusively female panel.

For the astronauts and for us on the ground too

If VIVALDI is organized around 20 women, it is because they are much less likely to have been in space than their male counterparts. Out of a total of 574 different astronauts (at the time of publication of this article), out of only 67 women. “In this area of ​​research, there is almost no knowledge on the physiological and psychological effects on women.»Underlines Angélique Van Ombergen, head of life sciences at ESA. The study therefore aims to increase the available data on certain effects of weightlessness (simulated with dry immersion) on the female body. The goal is “better understand the phenomena felt by astronauts in flight, better understand their mechanisms and develop measures to better prevent them», Explains Marie-Pierre Bareille, head of the study at MEDES.
Since two basins called MEDSIM (or automatic water immersion systems) are in service, the volunteers will follow one another in pairs with the program 4 days dedicated to basic measurements, 5 in dry immersion, then 3 days of post-immersion studies and recovery. To avoid a break in the conditions simulating the effects of weightlessness, the volunteers take their daily shower or go to the toilet when leaving the pool, but tilted 6 ° upside down. Medical surveillance is obviously uninterrupted.
In addition, VIVALDI does not provide data applicable to astronauts. There are also lessons to be learned for those who will not go into space. Marie-Pierre Bareille explains that “these models also make it possible to study the effects of a sedentary lifestyle on the human body ”. She concludes that “it will therefore also be used for medicine on Earth“.

When possible, examinations are carried out while the volunteers do not leave the dry immersion device.
Credit: MEDES

Built with the support of the State and local communities (Midy-Pyrénées Region, General Council of Haute-Garonne and the City of Toulouse), the Space Clinic is accredited by the Ministry of Health and the French Medicines Agency , for the evaluation of medical devices, clinical physiological research and drug research.