Astronauts could hibernate like bears
Astronauts could be able to survive long space missions by being artificially put into hibernation like black bears, scientists have claimed.
Alaskan black bears hibernate for up to seven months a year, during which time they do not eat or drink, before waking up in virtually the same physical state they fell asleep in.
By reducing their heart rate to only 14 beats per minute and slowing their metabolism by three quarters, the animals are able to remain healthy through their long period of inactivity.
Now experts hope to develop methods of putting humans into a similar state, which could help astronauts survive long missions and lead to new ways of treating severely ill patients, The Guardian reported.
While many studies have examined hibernation in mice and hedgehogs, little research has been done into the same condition in larger mammals such as bears.
But new research conducted at the Institute of Arctic Biology at the University of Alaska monitored the animals' body temperature, heart rate and muscle movements while they slept.
The results, published in the journal Science and announced at the annual meeting of the American Association for the Advancement of Science, showed that during a five-month hibernation the bears' body temperatures varied between 30C and 36C (86F and 97F) in cycles that lasted between two and seven days – a pattern that was previously unknown in hibernating animals.
When they awoke, the bears' metabolisms did not revert to normal for up to three weeks, suggesting that their bodies were able to somehow suppress them.
Øivind Tøien, who led the study, said: "If our research could help by showing how to reduce metabolic rates and oxygen demands in human tissues, one could possibly save people.
"We simply need to know how to turn things on and off to take advantage of the different levels of hibernation."
Craig Heller, of Stanford University, who contributed tot he study, added: "There has always been a thought that, if there is ever long-distance space travel, it would be good to be able to put people into a state of lower metabolism or suspended animation. That's almost science fiction but you can see the rationale."