Adults usually need, on average, seven to nine hours sleep a night
Concern about the economy is keeping about half of people in the UK awake at night, an online poll suggests.
Nearly half of the 1,000 men and women surveyed by NetDoctor said they were sleeping worse now than a year ago.
One-fifth of them are regularly getting fewer than five hours sleep a night and a quarter wake up more than three times a night, the survey suggests.
Stress was cited as a major factor, with two-thirds blaming money and work worries for their insomnia.
Snoring was also a contributing factor, with 30% complaining that their partner's snoring keeps them awake at night.
NetDoctor carried out the survey after noticing a surge in hits to its website from users looking for advice on insomnia.
Half of those who responded to the online questionnaire said they would like to sleep longer than eight hours per night, if they could.
Yet less than a fifth (17%) were able to.
One in 10 said it takes two hours or more for them to get to sleep each night.
And of those who wake during the night, 63% find it hard to get back to sleep.
NetDoctor's independent adviser Dr Roger Henderson said: "Sleep-related problems are surprisingly common, and something we all experience from time to time. However, the results reveal a worrying increase in the number of people suffering from sleep problems.
"It is important to remember that there are a number of simple ways in which to ensure a more restful night's sleep. Avoid stimulants such as caffeine and opt for a milky drink such as hot chocolate."
Jessica Alexander from The Sleep Council said other organisations had noticed similar trends lately.
"Sleep problems have seemed to increase in line with these current financial worries.
"Worry and stress affects people's sleep. The troubled economy and threats of recession have created mass panic and hysteria even among people not directly affected yet.
"The approach we would take is to try to encourage people to find ways to relax before bedtime.
"It is different for every person, but you might try a having a warm bath or reading a book - anything that breaks your train of thought.
"And if you find you are lying in bed tossing and turning, sometimes it is better to get out of bed and do something different until you are sleepy."