A group of 12 volunteers are sticking to a strict bed routine for 60 days, lying with their feet up and one shoulder always touching the mattress. This reclined lifestyle includes meals, showers and toilet breaks, as well as intensive cycling and centrifuge rides for some.

The BRACE study follows a two-month bedtime schedule to investigate how cycling and artificial gravity could counteract changes the human body experiences in space.

Astronauts face similar physiological problems as elderly and bedridden patients on Earth. During space missions, astronauts’ bodies go through a wide array of changes – everything from their eyes to their heart might be affected, and their muscles and bones start to deteriorate. To battle this degradation, crew members exercise two hours per day on the International Space Station.

The BRACE study involves male participants between the ages of 20 and 45 years with good physical and mental health. They are placed in beds tilted 6° below the horizontal position. As blood flows to the head and muscle wears out from lack of use, researchers chart how their bodies react.

Researchers split the volunteers in three groups. One group cycles in bed, a second one cycles while being spun on a centrifuge, and a third control group stays in bed for the full two months with no bike exercise or centrifuge rides. The centrifuge mimics artificial gravity, acting on all organs at once. Volunteers are spun to drive blood towards their feet, where the force of gravity doubles during the ride. Scientists hope artificial gravity could be used to keep astronauts fit and healthy in space.

Now halfway through its second edition, the experiment will finish on 4 May 2024, after 95 days of intense clinical testing and monitoring. This campaign takes place at MEDES, the Institute for Space Medicine and Physiology in Toulouse, France, and is supported by the French Space Agency CNES.

The study involves 14 European and international science teams that are working to release the results from the first BRACE campaign that took place in 2023. Researchers are assessing a wide range of changes in the cardiovascular, metabolic, musculoskeletal, neuro-sensorial, haematological, and immunological systems.

The tests will provide a better understanding of the effects of prolonged bedrest to the benefit of those in space and on Earth. Results could help design countermeasures and improve health for patients suffering from accelerated ageing due to a sedentary lifestyle.