Want to live to 100? Get a good night's sleep

But while following such sage advice might bring certain benefits, research released today reveals if you want to reach your 100th birthday and beyond you should throw away the alarm clock and get at least ten hours' sleep each day.

Researchers who carried out the largest study yet into the sleeping habits of exceptionally old adults – including 2,800 who were 100 or older – say good sleep is highly significant to longevity.

Dr Danan Gu, of Portland State University, Oregon, whose findings are published the journal Sleep, said: "Surprisingly, the oldest adults, aged 100 and above, were 70 per cent more likely to report good sleep quality than younger participants aged 65 to 79, after controlling for variables such as demographic characteristics, socioeconomic status and health. Those who were 100 years of age and older were less likely than the youngest elders to sleep for five or fewer hours per day, but they were almost three times more likely to sleep for ten hours or more.

"About 65 per cent of the sample overall reported that their sleep quality was good or very good, and the weighted average daily sleep time was about 7.5 hours, including naps."

Dr Gu added that men were 23 per cent more likely than women to report sleeping well.

Those in poor health, including anxiety sufferers, were 46 per cent less likely to report good quality sleep.

Adults aged 80 and over tended to sleep either shorter or longer than those aged 65 to 79, primarily due to deteriorating health.

The study involved analysing data from the 2005 wave of the Chinese Longitudinal Healthy Longevity Survey, with 15,638 participants spread across 22 provinces in mainland China. China's population of more than 1.3 billion people includes the largest elderly population in the world, making the country a valuable resource for studying healthy longevity. The World Bank estimates that China has nearly 40.5 million people aged 75 years of age and older.

However, Professor Colin Espie, a clinical psychologist and director of the University of Glasgow Sleep Centre, said: "I'm a little surprised about these results, as evidence from previous studies has shown extremely long or short sleepers tend to have more morbidity.

"Also, with longer sleep there could be indications that people are very tired, not very well, not recovering from the stresses of the day, or that they have problems with their immune system.

"But sleep is not a lifestyle choice, like something like exercise, where you can set yourself a regime. One can try and improve one's sleep, but you can't be a long sleeper if you are a short sleeper."

Professor Espie said that, rather than try to sleep for ten hours in an attempt to live to be 100, it was more effective to examine "sleep efficiency", looking at the proportion of a night's sleep which was successful and could be measured.

"Instead of going to bed and sleeping only six out of eight hours, it would be more "efficient" to go to bed for six hours and sleep for those six hours," he said.