Sen— Twelve volunteer 'pillownauts' are currently halfway through their second three-week session lying down with their heads angled at 6 degrees below the horizontal, to help research the effects of weightlessness on the human body.
The bedsuit shown in the image above, is part of a system to estimate energy requirements. It measures how much oxygen is consumed and how much carbon dioxide is exhaled by the volunteer. These measurements allow scientists to get an idea of the relationship between food, the lungs and the energy consumption when at rest.
Bedrest studies are helping to develop countermeasures against the unwanted physical effects on astronauts during long spaceflights and bedridden people on Earth. Astronaut's bones lose density by up to 2% a month during a stay in space. On Earth, similar bone loss is seen over a longer period of time, commonly known as osteoporosis.
Other changes that occur both in astronauts and bedrest volunteers include loss of muscle, changes in blood pressure and differences in how food is digested.
Bedrest resistive vibration exercise machine. Image credit: CNES - Emmanuel Grimault, 2012.
During bedrest studies, techniques to combat changes in our bodies are tested, from strict diets to specific exercise routines. For this study, in collaboration with France's CNES space agency, three bedrest campaigns are spread out over a year with 12 volunteers in each of three groups.
"ESA sends us the experiments they want to conduct. From there we start to look for volunteers, which is the most critical part of the organisation" says Marie-Pierre Bareille from the Medes institute in Toulouse, France, running this study.
The study requires many sacrifices from the volunteers. Not only are they expected to give up small pieces of their thigh muscles in regular biopsies, but they also have to remove themselves from their normal lives three times over the course of the year. The pillownauts undergo regular and intensive daily activities, including tests and examinations. They are not allowed to get up, not even for a shower or to use the toilet. Meals are strictly controlled during the study and cannot be tailored to participants. If you require a special diet for whatever reason, you cannot take part. During their time in bed, they cannot receive visitors and are expected to complete the session no matter what emergency at home.
Bedrest volunteer. Image credit: ESA
"We try to exclude people who we think are incapable of completing the study," says Marie-Pierre.
Rehabilitation after surgery or serious illness can mean weeks spent recuperating in bed. The research done on bedrest volunteers directly applies to these situations and is shared freely with scientists in all disciplines.
After this current 21 day study the pillownauts will have four months to recuperate, before returning for their final bedrest session later this year.