Moving the clocks back can lead to sleep problems after middle age.
But sleep problems, surprisingly, can occur after the clock goes back and we gain an extra hour, rather than when the clock goes forward.
Canadian researchers asked more than 30,000 people aged 45 to 85 about their sleeping habits at six different times, moving around the clocks.
They found no difference in sleep problems after the switch to summer time – which falls on the last Sunday in March in the UK.
But people’s sleep seemed to suffer after the clocks were turned back, as is the case in this country on the last Sunday in October.
Canadian researchers asked more than 30,000 people aged 45 to 85 about their sleeping habits during periods when the clocks change
After gaining an hour of weight, people were more likely to regularly have trouble falling asleep and had trouble staying asleep, which affected how they functioned during the day.
They also felt more tired during their waking hours.
The problem is that our internal body clocks rely heavily on daylight to tell us when we should be awake.
To “reset” this body clock and get it in sync with our new sleep hours after the clocks change, sleep experts have said we need lots of daylight.
But during the autumn months there is less daylight available.
However, the authors also say there’s also a possibility that people simply sleep more poorly in the fall, as they generally feel more miserable about the dark nights and approaching winter.
Anyway, the study’s reassuring conclusion was that people’s self-reported sleep disturbance after the clocks went back was short-lived.
Dr. Ronald Postuma, senior author of the study, from McGill University in Canada, said: “The good news is that the sleep disturbances we observed after the switch to standard time were brief and were no longer apparent two weeks after the shift.”
The study, published in the journal Neurology, classified people as having insomnia if they took more than 30 minutes to fall asleep, on at least three nights a week, which affected their daily functioning, such as their sleep, at least moderately. work or concentration, and whether they were also dissatisfied with their sleep.
Of the 588 surveyed in the week before the clock went back, only 3.3 percent had this problem.
But it was more than twice as common among 573 people surveyed in the week after the clocks went back, affecting seven percent of them.
In the week after the clocks were turned back, people were 64 percent more likely to have “sleep maintenance insomnia” compared to the week before.
This meant waking up in the middle of the night, or too early in the morning, and finding it difficult to get back to sleep, at least three times a week, where it affected their daily functioning and they were dissatisfied with their sleep.
People reported twice as much difficulty staying awake during the day, at least three days a week, despite getting enough sleep of at least seven hours, when the clocks went back.
The problem may be even worse in the UK, where light levels vary even more between seasons than in Canada, where the study was conducted.
The study authors warn that they only asked how well people slept, rather than measuring it directly.
But while there was no difference in sleep problems after the clock went forward, people were 34 percent more likely to be dissatisfied with their current sleep patterns when asked about it the week after the clock went back, compared to the week before .
Previous studies have linked clock changes to an increase in accidents, including car accidents, and an increase in strokes and heart attacks.
Dr. Postuma said: ‘The interesting result, even more so than whether sleep is affected by clocks moving forward or backward, is that changing the clocks is linked to sleep problems, at least once a year (SUBS – please hold).
“However, we now know that the impact is small and is fading quickly.
‘If the clock goes forward, it also appears that people sleep nine minutes longer on average.’