Five hours' sleep a night has same effect on brain as being drunk, says professor

Studies have suggested that lack of sleep raises stress, which could lead to higher blood pressure and increased stroke risk. Photo / Thinkstock

People who boast about getting by on less than five hours sleep should be stigmatised like smokers because of the harm that tiredness can cause, a leading professor has said.

Prof Russell Foster, a neuroscientist from the University of Oxford, said lack of sleep was damaging health, with too many early risers trying to function with brain skills so impaired they could be drunk.

Studies have suggested that lack of sleep raises stress, which could lead to higher blood pressure and increased stroke risk.

Prof Foster called for a change in attitudes towards getting an early night.

"There certainly is a culture of, 'well I only had five hours of sleep last night, how fantastic am I?'" he said.

"In fact, we should be looking down on those sort of things; in the same way that we frown upon smoking, I think we should start to frown upon not taking our sleep seriously."

The neuroscientist raised concern that sleep deprivation could cause risks not just in jobs such as healthcare and transport, where dangers were obvious, but also could damage the quality of crucial decisions.

"We see this too much with really senior people," he said.

"Lack of sleep damages a whole host of skills - empathy, processing information, ability to handle people, but right at the top of the chain you get overly impulsive, impaired thinking, because of this problem.

"Look at banking, look at the recent decisions about the Greek crisis. We see major discussions going through the night which have a massive impact, and decisions are being made when skills are very impaired."

Baroness Thatcher slept for only four hours a night as prime minister, as did Winston Churchill during the Second World War - although he insisted on a two-hour nap in the afternoon.

Prof Foster said many of those who rise before dawn were unaware of just how badly it could affect the functioning of their brain.

"At four o'clock in the morning our ability to process information is similar to the amount of alcohol that would make us legally drunk, as bad as if we had a few whiskies or beers," he said.

In 2010, a University of Warwick study found that people who slept for less than six hours each night were 12 per cent more likely to die before the age of 65 than those who slept six to eight hours.

Prof Foster said the evidence about the increased health risks posed by night shifts was also compelling.

Studies have suggested that working night shifts speeds up the ageing process and is linked to increasing risks of cancer, heart disease and type two diabetes.