Taking our fascination with human ability to extremes

The limits of human endurance have mesmerised us since the dawn of civilisation, as Dean Willis reports.

How would you react to the prospect of being trapped underground with 32 other people in a shelter no bigger than a small one-bedroom flat until Christmas?

That is the horrific scenario facing the miners trapped 700 metres below ground in Chile as rescuers begin the mammoth task of excavating a new mine to reach them.

The men - one of them is pictured in a video camera still on the right - are surviving on mouthfuls of tuna and biscuits, with sips of milk, but the psychological strain is expected to be the worst part of their four-month ordeal.

Their story has horrified and enthralled in equal measure, as billions around the world await what they hope will be another miraculous story of human fortitude.

Our ability to survive situations which should kill us has proved a point of fascination since ancient times. These are just some of the feats which defy belief.

How long can we survive without food or water?

The longest recorded starvation was by the Irish Republican Kieran Doherty, 25, who died in the Maze prison in 1981, after fasting for 73 days, only drinking water. With a supply of vitamins and water, however, people have been known to survive for more than a year without eating. Technically, your body will stop functioning when it uses up its last reserves of fat, protein and carbohydrates, but retired clinician Jeremy Powell-Tuck, who fed David Blaine after his starvation stunt in London in 2003, says: "You're more likely to die before then." Fat people would only be able to survive for longer if they had enough vital water-soluble B vitamins to help metabolise fat stores. It is possible that a person could die of starvation and still be fat. The most important things for survival are water and vitamins. With water, but no vitamins, most people would survive a matter of weeks - but without water they would be dead in days.

How cold can we get and still live?

On May 20, 2000, 29-year-old medic Anna Bagenholm was out skiing, fell under a waterfall and got wedged beneath thick ice. Submerged in freezing water for 40 minutes, Dr. Bagenholm's body temperature dropped to 13.6C - almost 24C below normal body temperature. She was clinically dead when she arrived in hospital in Norway and was unable to maintain a heartbeat for nine hours. Yet, not only did she survive but within nine months she was back at work and on the ski slopes again. Cooling is known to reduce the body's need for oxygen. Dr Mark Roth, of Seattle's Fred Hutchinson Cancer Research Centre, believes Dr Bagenholm's case offers evidence that humans could possibly remain in suspended animation for long periods.

How long can we go without sleep?

US teenager Randy Gardner got up at 6am on the morning of December 28, 1963 and didn't go back to sleep again until the morning of January 8, 1964. Those 264 hours - or 11 days - remain the longest scientifically verified spell that anyone has gone without sleep. Researchers at Stanford University School of Medicine who observed him said he did not take any stimulants, but relied on prompting to keep him awake. He did, however, suffer hallucinations, slurred speech and mood swings.

How long can we survive underwater without extra oxygen?

French free diver Stephane Mifsud held his breath for an incredible 11 minutes and 35 seconds on June 8 last year, setting a new world record for "static apnoea", or stationary breath holding. Competitors in these contests lie face down in cold water, which encourages outer blood vessels to constrict, sending blood towards the heart and brain, slowing your heart rate and the speed at which oxygen is pumped around your body. Without the divers' tricks and training, most of the rest of us can manage to hold our breath for less than a minute.

How fast can we run?

In 1960, the world wondered whether a man would ever run the 100 metres in less than ten seconds. Today, Usain Bolt's world record stands at 9.58 seconds. Dr Edward Coyle, who spent seven years working with cyclist Lance Armstrong to improve his performance, says: "I expect world records in athletics will continue to be broken and that we, at this time, might have a hard time imagining the performances that people will one day achieve."

How much can we lift?

British weightlifter Andy Bolton holds the record for the heaviest dead lift ever recorded after hoisting 457.5 kilograms - the equivalent of seven average British men - from the floor to his thigh. Most men cannot lift much more than their own body weight, but scientists believe that Bolton's feats are close to the limit of human potential.

How much can we remember?

Ever struggle to remember your new mobile phone number? Well envy one of the current world record-holders for memory feats, Chao Lu of China, who was able to accurately recite 67,890 digits of pi from memory in 2005.