Hibernation is not just sleep. While we sleep, our brains fire up and become highly active; in hibernation, on the contrary, brain activity completely slows down. The body temperature of hibernating animals also drops, in some cases close to the freezing point. Cells (细胞) stop dividing and heart rate decreases to two beats per minute. Yet, once it's time to wake up, hibernating animals come back to life without any significant side effects like freezing, muscle loss, or loss of bone density during the long winter months. The same, however, can't be said about people who wake up from long-term medical comas (昏迷), or even those who have to stay in bed for long periods of time. Such people, just like astronauts in microgravity, would suffer from a wide range of side effects that come from not actively using their bodies.

Scientists are therefore looking into hibernation research with the aim of developing ways to cause hibernation in future space astronauts. Recently, Kelly Drew, a professor of chemistry and biochemistry, has been rewarded for his research. 

The idea is that rather than having astronauts sit for months in a tiny Mars-bound capsule, consuming food, water and air, and gradually wasting away from not doing much in microgravity, a part of the crew members could be placed into hibernation. The hibernating astronauts wouldn't need any food or water and could manage with much less air—yet they would wake up with their bones and muscles in a much better condition than those of their awake counterparts.

"This research could be used to help future missions, from the extreme of medically caused hibernation for long term space missions, protecting astronauts from cabin fever, radiation, and much more," he said. "It could also prove effective in preventing muscle and bone loss in zero gravity. "

The state of hibernation could also help in the medical setting to help protect patients suffering from life-threatening conditions such as heart attacks and strokes. 

"This could mean that patients who have suffered from a stroke or heart attack could be placed in medically caused hibernation until they can be transported to a hospital to receive care, which could significantly improve medical outcomes," the scientist said.