The next time you are tempted to hit the snooze button on your alarm clock, hold fire.

Research suggests that early risers are slimmer, happier and healthier than those who get up later in the day.

Worst off are night owls, with late nights seemingly taking their toll on health and happiness.

Roehampton University researchers quizzed almost 1,100 men and women about their health and sleeping habits.

Some 13 per cent of those questioned were larks, getting up before 7am during the week and seeing no need for a lie-in at the weekend.

Night owls, who fall out of bed just before 9am Monday to Friday and sleep in on Saturdays and Sundays, accounted for another 6 per cent.

The remaining 81 per cent fell somewhere in between.

The analysis revealed the early risers to have fewest signs of depression and anxiety.

They were also more likely to eat breakfast - something that has previously been linked with slimness, a British Psychological Society conference heard.

Researcher Dr Jorge Huber said: 'These effects are small - and in some occupations and situations there are clearly advantages to being an evening person - but they are highly statistically significant.

'If you are an evening type, you are not necessarily a miserable person but there is some difference.'

He isn't sure of the cause, but it may be that late bed times make for a worse night's sleep.