Human hibernation breakthrough that could send us to sleep for months

Now researchers claim they are close to the breakthrough that will enable them to put astronauts into a state of suspended animation to make deep space voyages to faraway planets.

Human trials are planned this year to chill volunteers so they go into 'induced hibernation' and sleep safely, possibly for months.

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Research teams in Boston, Los Angeles and Pittsburgh are racing to be first to successfully carry out the procedure.

The American teams developed an injectable mix of salt and ice to cool the blood quickly.

The plasma rapidly sends body temperature from 98.6f (37c) down to 50f (10c).

The mixture puts the human body into hibernation by slowing the metabolism, delaying the onset of shock and limiting wound damage, said researcher Hasan Alam, a surgeon at Massachusetts general hospital and a consultant to the U.S. army.

So far it has worked on pigs, sending them into a state of suspended animation for several hours.

But other researchers at the University of California, Los Angeles, and the Safar Centre for Resuscitation Research at the University of Pittsburgh, believe this could be stretched to days, then weeks, and months.

The scientists say those in hibernation will need to be fed intravenously on a drip-feed.

Hair and nails would still grow and hibernating people would still age, just like those who have fallen into a coma do.

The researchers also point out another potential difficulty: Human waste would have to be dealt with.

Of the animals that hibernate, only bears seem not to have this problem.

The breakthrough is a spin-off from three arms of research: Into the apparently miracle recovery of those who have shown no signs of life after 'drowning' in icy water; into better ways to treat troops with serious injuries; and into bringing heart attack victims back to life who have been 'dead' for several hours.

Nasa, the U.S. space agency, abandoned work on induced hibernation 20 years ago, but the European Space Agency has been quietly taking another look at it for the last three years.

American researchers followed suit - and the idea got a major boost last December after a Japanese businessman, Mitsutaka Uchikoshi, 35, was found on a snowy mountain side 24 days after vanishing.

When searchers discovered him, Mr Uchikoshi appeared to be in a frozen coma. His pulse was almost undetectable.

His body temperature had dropped to 71f (22c) and his organs had mostly shut down.

He was treated for hypothermia-multiple organ failure and blood loss from his fall. Remarkably, he recovered fully with no lasting ill effects.

When rescuers found Mr Uchikoshi, who broke his hip when he slipped and fell down the mountain, he had lost a lot of weight.

Until becoming unconscious the businessman had survived by sipping the remains of a bottle of barbecue sauce that he had been carrying with him when he fell.

His doctors believe he survived unscathed because he went into some kind of frozen hibernation.

One of his doctors said: "He was frozen alive and survived. If we can understand why, it opens up all sorts of possibilities for the future."