Staying in bed for 60 days… that may sound like bliss, but add to the equation a shoulder constantly in contact with the mattress, exercise on a bike, centrifuge sessions and constant medical tests, and it becomes a real challenge in the interest of human space exploration.
A group of 12 volunteers are currently experiencing a bedridden journey, inclined at -6°. Participants are kept in beds inclined 6° below the horizontal, with their feet higher than their heads, throughout the day, including meals, showers and toilet breaks.
In this position where blood is directed to the head, where muscle mass is diminished due to underuse, researchers study how their bodies react. Bed rest studies offer a way to test measures to counter some of the negative aspects of life in space.
During space missions, astronauts’ bodies undergo a wide range of changes due to the lack of gravity. Everything from their eyes to their hearts are affected; muscles and bones even begin to degrade.
Bike and centrifuge
The BRACE (Bed Rest with Artificial Gravity and Cycling Exercise) study is investigating how physical activity on a bicycle, combined with centrifugation, could counteract the changes that the human body undergoes in space.
The bikes are adapted to be used in a lying position and on a centrifugal device to simulate gravity. The volunteers are rotated to direct blood to their feet, where the force of gravity doubles during rotation. The intensity of the centrifugal force is adapted to each individual according to their tolerance to hypergravity.
“We encourage volunteers to reach a submaximal effort on the bike every day, and then compare the impact with those who don’t exercise at all,” explains Rebecca Billette, medical director of clinical research at MEDES , the Institute of Space Medicine and Physiology in Toulouse.
The researchers will compare data from volunteers who cycled in bed with those who cycled in a centrifuge, as well as with a control group whose volunteers will remain in bed for the full two months without cycling or using the centrifuge. “We will compare the impact of a daily exercise routine on a variety of physiological factors,” adds Rebecca Billette.
This is the first time that cycling has been part of a bed rest study in Europe.
“We hope to understand the added value of artificial gravity in the fitness routine followed by astronauts on the International Space Station. The crew exercises two hours a day in orbit,” explains Angelique Van Ombergen, head of life sciences at ESA (European Space Agency) in the Human and Robotic Exploration division .
Artificial gravity is promising because it acts on all human organs at once. “This could become an effective solution to keep a healthier body during long-duration space missions, if the technological challenges can be overcome,” adds Angelique Van Ombergen.
Space for Medicine on Earth
Astronauts face similar physiological problems to those of elderly, bedridden patients on Earth. Long stays in orbit take a toll on their muscles and bones.
“Results from space analogues can be useful for designing better treatments for the elderly and patients with musculoskeletal disorders and osteoporosis on Earth,” says Angelique Van Ombergen.
Since 2001, the ESA has regularly organised bed rest studies of varying duration, with both men and women.
This study is supported by the French space agency CNES (Centre National d’Etudes Spatiales). BRACE builds on a previous study focusing on artificial gravity, conducted by ESA with the US and German space agencies in 2019 at the German Aerospace Center, DLR’s ” :envihab” facility in Cologne, Germany.
The next step for a simulated space flight with 12 other volunteers will take place in Slovenia at the Jožef Stefan Institute .
The researchers will conduct a new series of 60-day studies combining vibration exercise and artificial gravity