How much sleep do you really need? Read our chart to find out
The guidelines on what constitutes a good night's sleep have been revised. As little as five hours and as much as 11 hours may be appropriate for adults depending on age, doctors now say.
Just how much sleep do we really need? While new recommendations released last month have not changed - seven to nine hours each night for adults is still advised - experts now acknowledge that what constitutes a good night's sleep varies among individuals.
So they've come up with a new range: six hours of sleep "may be appropriate" for adults aged 18 to 64, says the expert panel convened by the US National Sleep Foundation in a report which was published in the foundation's journal, Sleep Health.
These new guidelines may come as relief for Hongkongers, many of whom are sleep deprived. The most recent Health Department statistics from 2011 found that 35.5 per cent of adults slept fewer than seven hours a day on average. Only 6.4 per cent of the 2,000 adults polled got more than eight hours of sleep a night.
Another survey released in 2010 of 5,000 Chinese adults in Hong Kong, led by Dr Wong Wing-sze, an associate professor at the Hong Kong Institute of Education, found that the average sleep duration was just six hours, 27 minutes.
Individuals with sleep durations far outside the normal range may ... have serious health problems
But while some people may operate perfectly fine on just six hours of sleep, the National Sleep Foundation expert panel emphasises that seven to nine hours is still ideal.