An extra hour's sleep? We should be so lucky as research shows adverse effects on health

A lot of people dread the clocks going back an hour in winter - but reassure themselves that at least they'll get an extra hour's sleep

- writes Melanie de Lange, epidemiology PhD student at the University of Bristol.

This 'springing forward' and 'falling back' is widely thought of a loss of one hour of sleep in spring and a gain of one hour of sleep in autumn. However, research suggests we may lose sleep for about a week after both clock changes as we struggle to adapt to the new time.

Previous studies have relied on people reporting their own sleep patterns in diaries or surveys. This may not be accurate because people sometimes forget how long they slept for.

Recent research has overcome this problem by using activity monitors to record people's sleep over the clock changes. But until now researchers have only been able to do this in a small number of people.

Our new study explored the effects of the clock changes on objectively-measured sleep duration in a large number of people who are signed up to the UK Biobank, a research database with lifestyle and health information from half a million UK participants.