A female skier made a full recovery after she fell into icy water and her body temperature dropped to just 13.7degC. Normal body temperature is 37degC.

Anna Bagenholm, 29, was brought back to life after being clinically dead.

Her case is reported in The Lancet medical journal by Mads Gilbert and colleagues from the University of Tromso, Norway.

Anna was submerged in icy water for more than an hour after a skiing accident.

She was skiing down a waterfall gully near Narvik in north Norway when she fell head first into a river.

Her head and body became wedged under thick ice, and her friends could not free her.

She found an air pocket and struggled for 40 minutes before she fell still. It was another 40 minutes before her friends cut a hole in the ice and dragged her out downstream.

Anna was accompanied by two medical colleagues, who called an emergency medical dispatch centre by mobile telephone.

She was ventilated with oxygen and given cardiopulmonary resuscitation (CPR) during a one-hour flight to hospital.

Once in hospital, she was warmed up using cardiopulmonary bypass. This allows the blood to be circulated and re-warmed outside the body by a machine that mimics the action of the heart and lungs.

She subsequently spent 35 days receiving ventilator treatment and a total of 60 days intensive care before rehabilitation.

Eight months on, Anna says the only lasting effect is a tingling in her hands.

Most die

In previous cases, patients who have suffered extreme hypothermia have died even after doctors had apparently successfully re-started their hearts.

Statistics show only a 10-33% survival rate for adults whose core body temperature drops below 28degC.

The previous lowest survived body temperature, 14.4degC, was recorded in a child.

Mads Gilbert said: "Victims of very deep accidental hypothermia with circulatory arrest should be seen as potentially resuscitable with a prospect of full recovery.

"The key success factors of such marginal resuscitation efforts are early bystander actions with vigorous CPR and early warning of the emergency system, early dispatch of adequate rescue units (ground and air-ambulances) and good co-ordination between the resources outside and inside the hospital, aggressive rewarming and a spirit not to give up."

Dr Jel Coward, a GP in Tywyn, north Wales, and an expert on wilderness medicine, said people suffering from extreme hypothermia often gave the impression of being dead, particularly as it can be difficult to detect breathing or a pulse.

He said: "This case really does bring it home to us how cautious one has to be before diagnosing death in people who are cold.

"There is an old saying that nobody is dead until they are warm and dead."