The science of sleep

Stefan Nigam 22 January 2013

Pulled an ‘all-nighter’ recently? Stefan Nigam separates myth from fact in his quest to uncover the importance of sleep…

The conventional wisdom passed onto Cambridge students by many a Director of Studies is this: you only have eight weeks, you can’t do everything.

Your options, then, are becoming a scholar, getting stuck into a society or sports team, or throwing yourself into the thrum of sweaty bodies and borderline alcoholism that is a typical Cindies night. Unless you are on the waiting list to join the Avengers or your name happens to be Gandalf, there is no way that you will be able to engage in all three of the above activities. Mere mortals will have to settle for two and be happy.

Typically, many Cambridge students seem to feel that the rules of mortality do not apply to them. Most students make it through the majority of their time here without sacrificing any one of the above aspects of Cambridge life.

‘How do they do it?’ asks the sceptical Director of Studies eight weeks later at the end of term meeting, having just been proven dramatically wrong. Whether they are sprinting right off the stage of an ADC lateshow to their favourite nightclub, or heading to the boathouse after pulling an all-night library session, everybody, at some point, sacrifices a few solid nights of precious shut-eye.

By ditching a few extra hours of sleep, or indeed sleep altogether, some students find it in themselves to defy common logic and maximise their time at university. They follow in the footsteps of role models such as Napoleon Bonaparte and Margaret Thatcher who both famously lived on four hours of sleep a night, and Thomas Edison who simply claimed that “sleep is a waste of time.”

But what exactly is at stake here? Aside from making awful first impressions whilst in a caffeine-induced delirium, what sacrifice is everyone really making by losing their beauty sleep? To understand the secrets behind sleep, we will have to turn to science.

And science doesn’t tell us very much at all. Or at least nothing conclusive. Despite decades of research and countless theories, the question of why humans, and all other animals, need sleep remains more or less a mystery. But, as anyone who has had to suffer the presence of the sleep-deprived can attest, need it we certainly do.

Without sleep, people become slow, irritable, forgetful and, at worst, delusional. Staying awake for seventeen hours straight has been proven to reduce your performance by the equivalent of two glasses of wine (a cheap, if rather lengthy, way to pre-drink perhaps).

At some point, everybody needs sleep, but the real question is why? Like explaining that people eat because they are hungry, the explanation that people sleep because they are tired seems to be somewhat lacking. How many times have you spent a whole day in a state of utter exhaustion, only to find yourself tossing and turning as soon as you actually go to bed?

Now would be a good time to get the nerdy stuff out of the way. Sleep occurs in a repeating cycle divided into REM (Rapid Eye Movement) and non-REM sleep. Non-REM sleep is further divided into four stages, during which we go from a light sleep to a deep sleep. Being awoken from deep sleep will result in grogginess and disorientation.

During REM sleep, which occurs seventy to ninety minutes into a sleep cycle, the brain becomes extremely active, more active than when we are awake, and this is the period in which most dreams occur. After REM sleep, the whole cycle begins again.

Using these findings can lead to some pretty advantageous sleeping habits. Knowing that sleep cycles are approximately an hour and a half long, try setting your alarms to these cycles. Waking up in light, non-REM sleep after sleeping for seven and a half hours will leave you feeling much fresher than if you woke up from a deep sleep after eight and a half hours.

There are four main theories that attempt to explain our need to sleep, namely: to heal, to rest, to dream and to learn. Theories that place emphasis on the need to heal and to rest have been thrown into doubt by the finding that a night of sleep in fact only saves about fifty kCal of energy (the same amount of energy that can be found in a slice of toast).

The idea that sleep is a means by which we can understand our self-conscious through analysing our dreams is one that was spread by psychoanalysts Sigmund Freud and Carl Jung. Freud developed a theory that the contents of dreams are all based on wish-fullfilment, with children, for example, dreaming about particular events that have sparked excitement the previous day.

Although the true answer probably lies somewhere in a combination of all four, currently the most popular and well-proven theory is that sleep is predominantly a chance for the brain to learn by processing and consolidating new memories. The idea that symbols in dreams could betray our own Oedipal fantasies is thus explained away; our brain is simply sorting through the events of the day.

This last theory is supported by extensive research that demonstrates a strong and positive correlation between sleep and memory retention. Studies undertaken by Professor Matthew Walker at the University of California have found that volunteers who had a decent night’s sleep performed significantly better in tests than those who had no sleep at all, but had the advantage of a bit more revision.

Furthermore, there is great news for those of you who swear by power napping. Research from Princeton shows that students who take ninety-minute naps after morning lectures consolidate that information, and perform better in afternoon studies, than those students who spend the same time socialising or revising.

So for those of you who are quick to knock off sleep as your first answer to finding more hours in a day, think again. Indulge yourself when you crave that little snooze in the library. Sleeping smart could be the path to success and, if not, well it’s a lot of fun and, in the immortal words of Ernest Hemmingway, “I love sleep. My life has the tendency to fall apart when I’m awake.”

Stefan Nigam