Margaret Thatcher famously got by just four hours a night and President Obama apparently survives on the same amount. Einstein, on the other hand, was a ten-hours a night man plus a couple of daytime naps. So how much sleep do we really need?
Experts are still arguing the toss. One of the UK’s most eminent sleep researchers Professor Jim Horne, who set up and for many years ran the Sleep Research Centre at Loughborough University, for example, argues that five or six hours ‘core’ sleep is all we really need for healthy brain function, and especially for the health of the cortex, the part of the brain that deals with thinking, speech, memory and perception. Once we’ve had that ‘core’ quota we spend the rest of the night in what Horne terms ‘optional’ or, more recently, ‘elastic’ sleep. Nice if you can get it but not strictly essential, he argues, for a healthy working brain. Worrying, unnecessarily, about not getting enough sleep can be counterproductive and actually cause insomnia.
Horne says ‘After a night of no sleep, the next night we regain less than half of that lost sleep, and feel fine. We regain all the lost ‘deep’ sleep found in the first five hours of normal sleep, which I still call ‘core sleep’ – it seems to be the sleep most beneficial to the slumbering cortex.’
Other experts disagree, however, and, especially in the US, there’s a vociferous lobby – and zillions of research papers – arguing that, today’s 24/7 society means that many of us are suffering ‘sleep debt’, a result of chronic sleep deprivation.
The consequences of this, they argue, range from low mood, to flagging memory, high blood pressure, inflammation and an increased risk of heart disease and dementia. According to one fairly recent US study sleep deprivation is responsible for 274,000 accidents and mistakes in the workplace each year. And several high profile disasters – from the 1979 nuclear meltdown on Three Mile Island to Chernobyl and the 1989 Exxon Valdes Oil spill – have been attributed to operator mistakes caused by lack of sleep.
We may never know how much sleep is optimum for all but it seems more than likely that, like everything else, sleep needs vary from one person to another – and they also change over the course of our lifetime (this will be the subject of another post). I know I’m not alone in that, as a teenager, I regularly slept in at weekends until 1 o clock in the afternoon. Nowadays, however, I’m awake with the lark – or to be more precise the first train of the day which rattles through the station near my home at around 5.30 a.m.
To work out how much sleep your body thrives best on, choose a time when you are not worried about anything and a morning when you don’t have to get up, and switch off the alarm. The number of hours from when you fall asleep to when you wake up – and feel alert and energetic the next day – is likely to be optimum for you. But even that is not set in stone. Sometimes you will need more – for example if you’ve done a lot of exercise or hard brain work – and sometimes you’ll need less.
If you can accept that and not fret if you don’t get the amount you think you need you’ll almost certainly sleep better for it.
© Patsy Westcott. Image © macrovector – Fotolia.com