For 264 hours, Randy Gardner did not go to sleep. He felt tired, but each time the urge to rest his head on a pillow came upon him, he played basketball and, after 11 days and nights in January 1964, he broke the world record for sleeplessness. He thanked his supporters, held a press conference and promptly passed out.

This achievement is being celebrated 43 years later (along with other sleep-related research) at an exhibition starting next week in North London. Scientists don’t really know exactly why we sleep, but the Sleeping and Dreaming exhibition at the Wellcome Collection will raise questions about whether we need to sleep at all. As science gallops ahead, would it be possible, one day, to take a pill and banish sleep for ever?

There are conflicting theories about the purpose of sleep. But the fact that we spend about eight out of every 24 hours asleep suggests that there are powerful evolutionary reasons for its continuing existence. Most theories centre on the beneficial effects that sleep has on the brain; this is because there is little evidence of any direct physiological effects on the body. Tissue seems to repair, regenerate and grow normally during times of sleep deprivation. Some scientists believe that sleep is a time for the immune system to regenerate, while one theory suggests that sleep evolved as a way of coping with limited supplies of food.

The dominant theory is that sleep is a time for the brain to store memory. The idea is that during sleep the brain, in effect, goes offline to file the events of the day. Another theory is that the brain is a complex organ that needs the downtime provided by sleep to recover from the stresses of waking hours. “While we are awake, the higher centres of the brain are working flat out,” says Professor Jim Horne, who runs the sleep laboratory at Loughborough University. “Even when you are lying down, the brain is in a state of quiet readiness, ready to respond. The only time it can rest is during sleep.”

He adds: “Sleep is important because we know that, even when people know they will die if they go to sleep, like shipwrecked sailors or overtired pilots, they still do so. Nature has provided nothing that overrides this.’’

Under five hours sleep is unhealthy

Researchers who champion these brain theories point to the fact that behaviour changes significantly with sleeplessness. A person who is lacking sleep takes more risks, has slower mental processes and reacts to events with more emotion and less logic. One theory is that brain circuitry needs to be repaired and maintained regularly and that when this maintenance work is not carried out during sleep, the workings go awry, with communications slowing down or being wrongly routed if you don’t get enough sleep. So how much sleep do you need?

Some research suggests that while seven to eight hours a night is healthy, under five hours or more than eight is unhealthy, and linked to disorders such as heart disease, depression, diabetes and high blood pressure.

However, there are reports of people surviving on less than five hours. Margaret Thatcher is reported to have run the country on four hours a night. “Some people claim that they can survive on very little sleep,” says Professor Horne. “But when we look into it, we find that Churchill and Thatcher took naps. Churchill had four hours a night and a two-hour siesta in the afternoon with his pyjamas on.”

Could a pill banish sleep for ever?

In our busy modern lives, however, sleep can sometimes be seen as nonproductive time, and many people would love to have an extra eight hours in their day. As a result, various research projects have been looking at how sleep needs can be reduced. Many chemical compounds that keep you awake – such as amphetamines and caffeine – have been examined but, so far, there has been no discovery of a drug that can safely replace sleep.

The US military has been funding research into genes. Keen to have soldiers alert for up to 72 hours a time, army scientists have homed in on a genetic mutation that has a powerful effect on the amount of time fruit flies sleep. In a four-year study, researchers at Wisconsin University screened 9,000 mutated fruit flies and found that one group slept a third the amount of normal flies. The gene involved is called Shaker and it is concerned with the flow of potassium into cells, a process that critically affects, among other things, electrical activity in nerve cells in the brain. Potassium also seems to be involved in the generation of sleep in human beings. The discovery could, the researchers say, lead to new ways of prolonging wakefulness.

Professor Horne, who is the author of Sleep-faring: A Journey Through the Science of Sleep, is sceptical: “Some people do suggest that we could have some sort of sleep pill that we can pop into the mouth and say goodbye to sleep, but I think it is largely nonsense. There must be 100 mechanisms in the brain that integrate sleep, and the idea that such a complex process could be changed by one pill seems nonsense.’’ He points out that no one knows the long-term effects of sleep deprivation. Eleven days is the most that anyone has gone without sleep, and Randy Gardner’s doctor described him at the end as being cognitively dysfunctional. It is also known that rats die after several days of sleep deprivation. And the Wisconsin research suggests that while the fruit flies needed much less sleep, they also died at an earlier age.

Would any of us, even the most time-pressed, really swap a long life with plenty of duvet-hugging for a short, sleepless one?

The Sleeping and Dreaming exhibition, the Wellcome Collection, 183 Euston Road, London NW1, until March 10. For more information, www.wellcomecollection.org

IF YOU SLEEP FOR LESS THAN:

4 HOURS Your immune system becomes compromised. When researchers at the University of Chicago exposed sleep-deprived students – four hours a night for six nights – to flu vaccine, their immune systems produced only half the normal number of antibodies. Stress levels rose, raising heart rates and blood pressure.

5 HOURS Your risk of diabetes increases. Research at Boston University School of Medicine suggests that those who have less than five hours a night were 2.5 times more likely to develop diabetes compared with those having seven to eight. You also increase the risk of being overweight. According to research at Bristol University, the rise in obesity may be partly because of the reduced amount of time we spend asleep. People who sleep for five hours were found to have 15 per cent more ghrelin, a hormone that increases feelings of hunger, than those who slept for eight hours. They were also found to have 15 per cent less leptin, a hormone that suppresses appetite.

6 HOURS Watch out for high blood pressure. A study reported in Hypertension suggests that those who sleep less than six hours a night had more than double the risk of high blood pressure.

IF YOU’VE BEEN AWAKE FOR:

10 HOURS Levels of the stress hormone cortisol begin to rise. There may also be changes in blood pressure.

12 HOURS The likelihood of having a car accident more than doubles. Heart rate begins to slow.

17-28 HOURS Speed in mental tasks slows to the equivalent of someone who has drunk the drink-drive legal limit of alcohol.

24 HOURS Risk-taking behaviour increases. Verbal fluency declines.

48 HOURS Effectiveness of immune system declines.

53 HOURS Ability to make moral judgments declines.

72 HOURS Speed and accuracy in computer tests drop to 30 per cent of normal.

85 HOURS Brain activity declines significantly.

11 DAYS Longest documented period of voluntary sleeplessness is 264 hours. No long-term harmful effects found.

Sources: US Federal Highways Commission; University of New South Wales; University of California, San Diego; North Carolina University; Walter Reed Army Institute of Research; Johns Hopkins University

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