At France's Medes Institute for Space Medicine and Physiology, 20 women are currently tucked into strange bathtub-like waterbeds as part of a study on how spaceflight might specifically impact females. Each volunteer is wrapped in a waterproof sheet up to their chest and then lowered into a large bathtub. Apparently similar experiments—called dry immersion studies—have been conducted on men but "there is almost no knowledge about the physiological and psychological effects on women in this research area," says the European Space Agency life sciences lead Angelique Van Ombergen. From Phys.org:
Volunteers will have limited motion in a monotonous environment and experience changes in body fluids and mobility, as well as in the perception of their own bodies. Results could have great potential to investigate detrimental effects of spaceflight and movement disorders for immobilsed and elderly patients on Earth[…]
Volunteers spend almost 24 hours a day in the immersion tank, limiting their movements as much as possible. Each day starts at 7 am with urine and blood samples, and it is filled with scientific protocols and measurements to study how the body adapts.
All activities from leisure to hygiene are done within the constraints of immersion. Only a small pillow is allowed during meals to ease eating. Showering and transfer to other experiments are done outside of the tank while lying on their backs and with their head tilted 6 degrees down to minimize fluid shifts.