Space travel is incredibly taxing on the human body – and ironically, one of the best ways to simulate that is by staying in bed for long periods. The lack of gravity in space means that muscles and bones begin to waste away, and scientists have been studying these health effects on Earth with extended bed-rest experiments. In the latest of these studies, those beds will be put in a centrifuge to mimic artificial gravity, to see if that can help offset the issues.
Millions of years of evolution has fine-tuned our bodies to rely on Earth's gravity to function. Our fluids drain downwards, and just by supporting our weight our muscles get at least a little constant exercise. Take gravity away and muscles quickly atrophy – which is why astronauts on the International Space Station have to spend more than two hours a day exercising rigorously.
Here on Earth, good way to mimic the effects of low gravity is to have people lie in bed for long periods, often several weeks or even months at a time. This keeps muscles from being used and lets blood pool in people's heads, which tends to happen in space. Then, scientists can experiment with different techniques, diets and exercise regimes to figure out the best way to help astronauts.
The new study, conducted by the ESA and NASA, will follow that structure. It's due to kick off on March 25, when 24 participants will lie down for 60 days in the :envihab test facility in Cologne, Germany. They'll have to lie with their heads tilted six degrees below horizontal to get the blood pooling just right, and one shoulder must be touching the mattress at all times. And after the initial two months comes another 29 days of acclimatization and recovery.
One of the main things that the new study is testing for is whether artificial gravity could help counter the ill effects of space travel. Centrifugal forces are the easiest way to mimic gravity, and previous studies have found that spinning capsules could make exercising more effective in space.
So as part of this study, some participants will be put in a short-arm centrifuge, bed and all. By spinning them at high speeds blood will flow back towards their feet. The scientists can then study what kinds of effects this might have on their health, taking readings of their cardiovascular function, balance, muscle strength, metabolism, cognitive performance and other factors.
The intensity of the centrifuge can be changed to suit each person's size. The team also plans to investigate whether spinning around different central points – including the head and the chest – makes any difference.
With more and more humans hopefully heading to space in the coming years, these kinds of studies could be vital in helping to prevent a new epidemic of space sickness.
Source: ESA