The night before the Challenger space shuttle took off for its ill-fated final flight in January 1985, National Aeronautics and Space Administration (NASA) officials held a two-and-a-half-hour conference call with executives from the company that made the rocket boosters to discuss a potential fault. The subsequent investigation into the disaster, which killed all seven astronauts on board, concluded that poor decision-making at that meeting, which gave the go-ahead after much debate, was aggravated by the fact that two of the NASA managers had been awake for 23 hours straight and had slept for no more than three hours the previous day.

Similar errors during long night shifts were implicated in the nuclear disasters at Three Mile Island and Chernobyl, as well as the Exxon Valdez oil spillage. Meanwhile, the Automobile Association says that more than 3,000 deaths and serious injuries on U.K. roads each year can be attributed to sleep deprivation — as many as for drink driving. But new research published this week says that lack of sleep can harm us in more direct ways than, say, falling asleep at the wheel of a car. Researchers at Warwick medical school in central England published a study in the European Heart Journal that linked disrupted sleep patterns to major health problems. “If you sleep less than six hours a night and have disturbed sleep you stand a 48 per cent greater chance of developing or dying from heart disease and a 15 per cent greater chance of developing or dying from a stroke,” said lead author Professor Francesco Cappuccio.

Professor Jim Horne, director of Loughborough University's Sleep Research Centre, says the key to healthy sleeping is achieving at least six hours of “core” sleep a night — which includes the “deep” sleep during the first five hours of normal sleep. “Core sleep gradually gives way to what I rather loosely call ‘optional' sleep, which maintains sleep until morning awakening. After about six hours of good sleep, all core sleep has usually disappeared.” But he says that the idea of a “perfect” length of sleep is a myth: everyone is different. He therefore urges people not to assume that a few bad nights will give you heart disease or a stroke — with the subsequent worry only exacerbating your restlessness.

His tip for insomnia? Get up, leave the bedroom and do something distracting but mentally stimulating, such as a jigsaw.— © Guardian Newspapers Limited, 2011