Forget eight hours of sleep a night

Scientists say that despite the widely held belief that we need eight hours of sleep a night, six to seven hours is the natural amount.

What is more, it is a myth that modern living is robbing us of precious time in bed.

Advising short-sleepers to rest easy, the US researchers said: ‘This has important implications for the idea that we need to take sleeping pills because sleep has been reduced from its natural level by the widespread use of electricity, TV, the internet and so on.’

The University of California, Los Angeles, scientists spoke out after studying the sleep habits of three groups of hunter-gatherers.

The San, of Namibia, the Hadza, of Tanzania and the Tsimane of Bolivia were chosen because their traditional lifestyles that lack the trappings of modern life are thought to be similar to that of our ancestors.

Specialised watch-sized devices that measure sleeping and waking times as well as light exposure recorded more than 1,000 days’ worth of data for 94 adults.

Most of those studied slept for less than seven hours a night, with the average amount just six hours and 25 minutes.

This is much less than the eight hours often recommended in western societies.

Despite this, the peoples studied were in good health, with lower rates of obesity, better blood pressure and healthier hearts than people in industrialised societies. They were also fitter.

Ghandi Yetish, the study’s lead author, said: ‘There’s this expectation that we should all be sleeping for eight or nine hours a night, and if you took away modern technology, people would be sleeping more.

‘But now, for the first time, we are showing that’s not true.’

Colleague Jerome Siegel said: ‘The argument has always been that modern life has reduced our sleep time below the amount our ancestors got but our data indicates this is a myth.’

The study, published journal Current Biology, also cast doubt on the idea that we are going against nature by staying up after dark.

Despite not having electricity, the peoples studied did not turn in at dusk. Instead, they stayed awake for an average of three hours and 20 minutes after sunset.

Professor Siegel said: ‘The fact that we all stay up hours after sunset is absolutely normal and does not appear to be a new development, although electric lights may have further extended this natural waking period.’

The analysis also showed napping to be rare. As was insomnia, with two of the cultures not even having a word the disorder.

The findings do, however, provide some insight into how to deal with insomnia.

Lack of heating meant that rather than sleeping in rooms kept at a constant temperature, the mercury gradually dropped through the night.

Wake-up time coincided with the coldest point, even when it was after daybreak and resulting in roughly the same wake-up time each morning.

Professor Siegel said: ‘In most modern environments, people are sleeping in a fixed temperature, even if it’s reduced from daytime levels.

‘It may well be that falling environmental temperature is integral to sleep control.’

(dailymail.co.uk)