Health guidelines say people need between seven and nine hours every night.
But two thirds of adults admit they suffer from disrupted sleep and nearly a quarter get less than five hours per night.
Some 31 per cent of adults suffer from insomnia and 48 per cent say they do not get enough sleep, a study by Aviva revealed.
Dr Doug Wright, Medical Director at Aviva UK Health, said: “As well as suffering from general fatigue, people who regularly don’t get enough sleep are at higher risk of serious medical conditions such as obesity, heart disease and diabetes.
“Sleep deprivation can be very distressing and often has a negative effect on mental health.
“There are lots of methods available to help aid sleep, such as avoiding electronic devices close to bedtime, controlling light and noise levels and avoiding stimulants such as caffeine.
“Alcohol can also lead to disrupted sleep and a ‘night cap’ to aid sleep can actually have the opposite effect.”
Women, on average, get an hour’s less sleep than men with six hours per night and more than half of women (54 per cent) admit they do not get enough, compared to 41 per cent of men.
More than two thirds of adults say they suffer from disrupted sleep, including 74 per cent of women.
And 13 per cent admit to taking sleeping pills or drinking alcohol to aid sleep, Aviva said.
The survey of 2,235 adults revealed people living in Cardiff were most likely to suffer sleep deprivation with 37 per cent saying they had insomnia, followed by Sheffield on 36 per cent, then Glasgow and Newcastle at 35 per cent.
Dr Wright added: “More serious sleep disorders such as insomnia may be rooted in other issues, such as stress and mental health concerns, and would benefit from medical attention.
“Your local GP can advise on the most suitable course of treatment.
“The most important thing is to take persistent trouble sleeping seriously and not to suffer in silence.”