If F Scott Fitzgerald was right when he declared, "The worst thing in the world is to try to sleep and not to", then forcing oneself to stay awake for days on end must surely come a close second. This week we will get to see just how bad it is, as contestants on Channel 4's Shattered fight the urge to sleep for seven straight days in a bid to win £100,000.
The programme, which will be aired daily throughout the week, follows 10 contestants as they struggle not only with the ever-increasing lure of sleep, but also the mind-bending effects sleep deprivation brings. The relationships between the contestants are likely to change dramatically, but they will also notice big changes in themselves, changes that will be brought out by tasks designed to test their reactions, memory, time perception and mental agility. It might not make a pretty sight. By midday yesterday one of the contestants, Ellen, a 28-year-old flight attendant, had already gone after struggling with a memory task.
Unsurprisingly, considering that we spend a third of our lives indulging in it, sleep is a necessity - though it is more necessary for some than for others. Lady Thatcher famously claimed to need no more than four hours a night, while some struggle if they don't get their head down for 11. The average works out at around eight hours for a good night's rest. The bad news for the Shattered contestants is that how long you sleep is largely down to your genes. You can train as hard as you like to go without sleep - your body will still want the amount it is genetically programmed to need.
Cut sleep out and things rapidly begin to go downhill. One of the first signs that someone is suffering from sleep loss is that they start to become moody and irritable. "If someone teases them, they're liable to swing at them rather than take it as a joke," says Neil Stanley, chairman of the British Sleep Society and the resident sleep scientist on Shattered.
The brain, perhaps surprisingly, tends to be the only organ affected by sleep loss. "There's very little evidence that the body fails at all if you go without sleep," says Professor Jim Horne, director of the Sleep Research Centre at Loughborough University. "Provided you get adequate nutrition and physical rest, all of the organs from the neck down can cope fine."
Not so the brain, however. It's the one organ that really can't cope without sleep. Specifically, it's a region of the brain called the cerebral cortex that suffers the most. The cerebral cortex is arguably what makes us human. It governs what we think, what we say, what we do. "Without that, you become an automaton, a robot," says Horne.
And that is exactly what the acutely sleep-deprived turn into. The transition to human robot can kick in after just two days without sleep. "You end up just staring at things because you don't know what to look at next." Gradually, other symptoms begin to appear, like being easily distracted and unable to take part in conversations. "If you are in a conversation [with a sleep deprived person], they will most likely have stilted speech and speak in a monotone and not about anything at all interesting," adds Horne.
So what is it that periods of sleep, "those little slices of death", as Edgar Allen Poe called them, do for us? Essentially, sleep gives the cerebral cortex a chance to get enough rest so that it can start functioning normally again. "Even if you try and rest by shutting your eyes, plugging up your ears and lying on a bed with a mind clear of any thoughts, your cortex is not resting. Without sleep it just stops working," says Horne. Other parts of the brain do not work at such an intensity for all of our waking hours. Surprisingly little sleep is enough to rest the cortex, though - as little as two hours a night.
Sleep deprivation does more than turn you into a non-communicative vegetable, however. Sleep-deprived people have increased appetites, become shaky, get headaches and, mysteriously, get more horny. "If you consider that the average man thinks abou sex once evey 15 seconds, and you're awake for 24 hours a day, it's not surprising," says Stanley. As if to quell the urge, their bodies cool down a third of a degree.
After three days without sleep, hallucinations can kick in. The longest scientifically documented case of sleep deprivation was the provided by an American, Randy Gardner, in 1964, who, in an attempt to set a world record, stayed awake for 11 days. Four days in, he had a hallucination in which a street sign turned into a person, an episode quickly followed by a delusion where he though he was a famous black footballer. The hallucinations are due to what sleep scientists call dream intrusion. "If you deprive yourself of sleep, your body still needs to dream," says Stanley. "But because the dream is playing while you're still awake, you have two realities going on, so the hallucinations can seem very real."
Little is known about any long-term damage that sleep deprivation can cause. Studies in rats that were fed and watered, but kept awake until they died, showed that the animals eventually keeled over as their body temperature went haywire. They survived only 14 days, but as Horne points out, that's a long time for an animal that normally lives just two years.
Just how long a human can go without sleep is hard to judge, except to say that it is likely to be much longer than Gardner managed. After sleeping off his 11 day awake-athon, he showed no signs of long-term physical or mental damage. Horne says the idea that people kept awake for days will eventually go mad and start beating each other is nonsense. "What's far more likely is they'll just sit around and finally conk out."
Pushed to the absolute limit, however, the human body will ultimately succumb to sleep loss, although it would likely take more than 30 days of constant wakefulness. (The contestants in Shattered will attempt only seven days, be closely watched by doctors and allowed to grab an hour or two of sleep when they feel it is absolutely necessary.) Rather than the brain burning out, sleep deprivation would ultimately become fatal because of the stress it causes.
"If something was keeping you awake that long, you would have such a stress reaction that your immune system would probably collapse," says Horne. The result would be catastrophic. The immune system is constantly fighting small battles with microbes all over the body. When it collapses, the battle and the war are lost. "You would die of wholesale, massive infections. It would be like an extreme form of blood poisoning." The contestants will be grateful they are only awake for a week.
