Red Bull, ProPlus, sniffing eucalyptus oil, drinking shot after shot of espresso and taking ice-cold showers in the middle of the night – some students will do anything to stay awake when there's last-minute cramming to be done. It's not hard to realise that regularly overloading on copious amounts of caffeine in order to stay awake in the battle to finish tomorrow's presentation or read through a to me of lecture notes in the dead of night will invariably take a toll on your brain, body and academic performance. And yet it's something most students will have done at some point in their university career.

In the final year of an art history degree at the University of Leeds two years ago, Chloe August found herself rushing to finish her dissertation on time . "Keeping the window open all night to keep cold, smoking cigarettes and taking ProPlus were all on the agenda," August says. "I also bought myself an espresso machine – the cheap ones that you could put on the hob – and at one point I was drinking 12 to 15 espressos a day.

"I do think this turned me a little odd and quite teary – excess caffeine
and not much sleep is not good at all. But it was worth it in the end."
At least August got her dissertation done on time – but for others, an all-
nighter can spell total disaster.

Jenna Gould survived on three hours sleep a night in the run-up to her marketing finals. "I was cramming in loads of research, eating nothing but cornflakes. I survived by having half-hour power naps when I got really tired in the day and then carrying on. After one particularly stressful exam, I suffered a migraine with really bad side-effects and ended up being taken to hospital – I'd lost the feeling on one side and started slurring."

Gould, who got a first and now runs her own marketing business, says it
was all worth it. "My goal was to get a first and you don't achieve that without a lot of blood, sweat and tears. But if I could do it again, I would definitely have looked after myself more, had a better diet, took longer periods to sleep and taken some vitamins. "It's not so much a lack of preparation or revision, it's more about making sure you help your mind and body cope with a few all-nighters which are inevitable, no matter how hard you work. The problem is, you think you are invincible."

Sociology graduate Kirsty Henderson did her finals last year at the University of Warwick. "We used to stay up drinking sugar-free Red Bull, coffee, Lucozade and taking ProPlus. A friend missed her contract law exam after an all-nighter because she overslept and then had to do retakes. Someone else spelt her name wrong on her exam paper after staying up all night before."

In the United States, studies have been carried out to investigate the impact that sacrificing sleep has on students. The results, published in the Behavioral Sleep Medicine journal, show students who pull all-nighters can suffer from delayed reactions, a tendency to make mistakes and lower all-round academic performance. "It's foolish to stay up all night before an exam – you
won't be able to think," says Professor Jim Horne who runs the sleep research centre at Loughborough University.

"When you are tired, nothing goes into your brain, so forcing yourself to
stay up is utterly pointless." Horne says that if you have left things to the last minute, you must prioritise sleep – his studies show the brain and body should get at least four hours' sleep to function.

"Instead of staying up the entire night, call it a day at 1am and sleep
until 5am. Then do two hours' more revision in the morning. You'll absorb more," he says. A one-off all-nighter is not ideal, but it is not damaging in the long term. If, however, you find yourself surviving on two hours' sleep every night for a fortnight or so in the run-up to your exams, you could be putting yourself at greater risk – both academically and physically.

Professor Francesco Cappuccio, at the University of Warwick's medical
school, explains: "Students often think they can go without sleep, that sleep is passive or wasted time – but when you sleep, your brain consolidates memory and what you have learned during the day. If you are sleeping less, your ability to retain information will be impaired – you will reach your exam fatigued and unable to remember facts."

Cappuccio says that if you are a "short sleeper" – someone who regularly sleeps less than five hours a day – then you are also more likely to develop coughs and colds or become prone to hypertension and diabetes. "You tend to fall ill when your body hasn't had a chance to recover."

If you do feel under pressure to get work done on time, avoid stimulants
such as black coffee and energy tablets or drinks – they may be short-term fixes to avoid sleep, but can end up making you feel worse. Horne says: "If you have too much of these things, then you can get hyperactive and worked up into such a state that you can't even take the exam. You can't survive on caffeine alone – it can delay sleep, but it can't displace it entirely."

Twenty-five-year-old Declan Shaw, is in his final year of architecture at
University College London. He routinely goes without sleep for at least one night a week. "There was a point in my third year when I was surviving on two or three hours' sleep every night over two or three weeks. That was really pushing it," he recalls, adding that most of his course colleagues do the same.

"It's much quieter to work at night and you have hours and hours to get it
done, although sometimes the night just doesn't feel long enough." And although Shaw says he doesn't feel tired after an all-nighter, he does suffer in other ways. "I definitely feel much weaker the next day – it's hard to cycle in the wind or I get tired walking up the stairs. And people sometimes say I look spaced out," he says.