"We see ourselves slimming day by day at the beginning," smiles Matthieu, one of the twelve men selected for this experiment, who has been well installed for five weeks at the Medes clinic, the health subsidiary of the National Center for Space Studies (CNES).

The bed of these volunteers, chosen from among 3,000 candidates and whose names are not communicated, remains inclined for 60 days at an angle of -6 degrees, the most likely to restore the effects of weightlessness to which astronauts are subjected during their stays in space.

"We have entered the space exploratory phase. We are really looking to go to the Moon and Mars, it is no longer a fiction and it involves long-term flights of two to three years, "said Audrey Bergouignan, of the National Center for Scientific Research (CNRS).

"Exposure to microgravity will impact all physiological systems (...) and cause alterations that we try to understand and prevent," says this research director, before adding: "To prevent them, we put in place protocols that we test upstream here, before testing them in space."

Bicycle and centrifuge

Everything is therefore organized in order to allow the 12 hospitalized to stay in bed: nearly a hundred people are mobilized to follow them for the duration of the study, from caregivers to researchers.

Two volunteers lie down during an experiment at the Medes clinic, the health subsidiary of the National Center for Space Studies (CNES), in Toulouse, May 23, 2023 © Lionel BONAVENTURE / AFP

"We are in very favorable conditions for bed rest, every time we need something just call the medical staff," says Matthieu, a 39-year-old market gardener that his girlfriend convinced to try the adventure, paid 18,000 euros for three months of presence on site.

In order to compare the evolution of their body according to their physical exercise, the volunteers are divided into three groups: one performs 30 minutes of lying cycling a day, the other is not subjected to any physical activity, while the third must pedal while in a moving human juicer.

"The idea is to see if the artificial gravity created by the centrifuge when it turns improves the effects of physical exercise of the bike," says Marie-Pierre Bareille, head of the space clinic to which the study was entrusted by CNES and the European Space Agency (ESA).

If the results are conclusive, this artificial gravity could be recreated on board long-duration missions in space, once the technical constraints are resolved.

Fifa and Mario Kart

"The challenge," she says, "is that crews are fit and able to work during spacewalks" during which they may have to perform quite physical tasks.

Medical staff study the data of a volunteer lying on a centrifuge during an experiment at the Medes clinic, the health subsidiary of the National Center for Space Studies (CNES), in Toulouse, May 23, 2023 © Lionel BONAVENTURE / AFP

"During a trip to Mars, astronauts could lose up to 15% of their mass," says Audrey Bergouignan.

The participants in the experiment take turns, sometimes on a bike designed to pedal lying down, sometimes in the centrifuge, while laughter erupts with the caregivers who share their very special daily lives.

"I'm not bored, everyone is very nice," said Alejandro, a 26-year-old Spanish aeronautical engineer who lives in Toulouse.

"We are in contact with the other rooms. We organize video game tournaments on Mario Kart or Fifa," he laughs, while pedaling under the supervision of a coach.

For them, the experience will end with an accompanied return to normal life at the beginning of July, while 12 other volunteers will submit to the same living conditions in 2024.

The clinic selected only men in order to "limit the variables" between the volunteers, according to the organizers, and obtain the most "homogeneous" results possible.

But the conclusions of the study conducted in Toulouse will not only apply to the space field. "Knowledge of hyper-sedentary lifestyle will be useful to everyone to know how the lack of physical activity acts on the body," says Marie-Pierre Bareille, referring to the elderly or suffering from pathologies such as osteoporosis.

© 2023 AFP