When the clocks go back at the end of daylight saving time, most people expect an extra hour of sleep, but research suggests it often does not arrive. Your body clock does not change overnight the way the wall clock does, so for several days you may feel sleepy earlier in the evening and wake earlier than you would like in the morning. For most people this settles within about a week, and a few gentle adjustments can make that week easier.
In the UK and Europe the clocks went back on Sunday 25 October. In the United States and Canada, daylight saving time ends on Sunday 1 November. Here is what is actually happening and how to make the change gentler, especially if you have a baby in the house or you are already waking too early.
Do you really get an extra hour of sleep when the clocks go back?
It is the classic promise of the autumn change, but the evidence is mixed at best. In a 2013 review in Sleep Medicine Reviews, Yvonne Harrison looked at research on daylight saving time and sleep. She found little evidence that people actually gain an extra hour of sleep on the night of the autumn change. In the days that follow, many people wake earlier than they used to, which can add up to a small net loss of sleep across the week.
The reason is simple: the clock on the wall moves, but the clock inside you does not. If your body is used to waking at 7 a.m. summer time, it will nudge you awake at what now reads 6 a.m. for a while. The extra hour on paper is often spent lying awake before the alarm.
How does the end of daylight saving time affect your body clock?
Your circadian rhythm is set mainly by light, especially morning light. It does not follow the time on your phone. Our post on circadian rhythm and sleep explains the system in more depth.
Research from Thomas Kantermann, Till Roenneberg and colleagues (2007, Current Biology) used survey data from around 55,000 people to look at how sleep timing changes across the year. They found that, under standard time, the timing of sleep on free days followed the seasonal shift in dawn, but under daylight saving time it did not. In other words, our internal clocks seem to track the sun, and the clock changes push social time out of step with that rhythm.
The American Academy of Sleep Medicine has taken a clear position on this. In a 2020 position statement in the Journal of Clinical Sleep Medicine (Rishi et al.), it recommended ending seasonal clock changes and adopting permanent standard time, on the grounds that standard time aligns more closely with the body’s natural sleep and wake rhythm.
The encouraging part is that the autumn change, which returns us to standard time, tends to be the easier one. It shifts the clock in a direction most body clocks adapt to more readily than the spring change.
How long does it take to adjust when the clocks go back?
For most adults, the adjustment takes several days to about a week. You might notice:
- feeling ready for bed an hour earlier than usual for the first few evenings
- waking before your alarm
- an afternoon dip that arrives earlier than you expect (see why do I get tired after lunch)
- darker evenings that make it tempting to wind down very early
None of this is a sign that something is wrong. It is the body clock catching up with the new time.
For new parents: when your 6 a.m. waker becomes a 5 a.m. waker
Babies and toddlers do not know that the clocks have changed. A little one who woke at 6 a.m. last week will often wake at what is now 5 a.m. on the clock, and naps and bedtime will drift earlier too. For parents already short on sleep, that hour can feel enormous.
There are two common approaches, and both are reasonable:
- Shift gradually. In the days around the change, move bedtime, naps and meals 10 to 15 minutes later every day or two until the routine lines up with the new clock time. Many families do this over about a week.
- Switch on the day. Some babies adapt well if you simply move to the new times straight away, especially older toddlers. If your child copes well with change, this can be quicker.
A few things support either approach:
- Keep the bedtime routine the same, just at the shifted time. The familiar steps tell your child it is still bedtime, whatever the clock says.
- Use daylight in the morning and dimmer light in the evening. Light is the main signal the body clock follows, for babies and adults alike.
- Consider blackout blinds if the earlier sunrise is waking your child before you would like.
If the early mornings are adding to an already significant sleep debt, sleep debt for parents has ideas for recovering where you can.
For perimenopause: when early waking gets even earlier
Many women in perimenopause already wake earlier than they would like, often in the early hours. When the clocks go back, a body clock that was waking you at 5 a.m. may wake you at what now reads 4 a.m. for a few days. That can feel discouraging, especially when sleep is already less predictable than it used to be.
A few gentle steps can help the adjustment:
- Get morning daylight soon after waking. Morning light helps anchor your body clock to the new time. Our post on morning sunlight and sleep explains why it is so effective.
- Hold your wake time steady. Getting up at the same clock time each day, even after an earlier wake, helps the body clock settle faster than lying in.
- Push bedtime slightly later for a few nights. If you feel sleepy very early in the evening, a little light activity and brighter light in the early evening can help you stay up closer to your usual time, so you are not waking even earlier the next morning.
If early waking is a pattern that lasts well beyond the clock change, waking up too early looks at the wider reasons and what helps.
How can you adjust to the clocks going back more easily?
- Get light in the morning, ideally outside, as soon as you can after waking.
- Keep your wake-up time consistent, including at weekends, for the week after the change.
- Ease bedtime later if you find yourself fading too early in the evening.
- Keep your evening light dim in the hour before bed, and bright earlier in the evening.
- Go easy on caffeine in the afternoon while your rhythm settles.
- Expect a few uneven days. A slightly bumpy week after the change is normal and usually resolves on its own.
If your schedule has drifted for other reasons too, how to fix your sleep schedule walks through a gradual reset.
The calm version
The clocks going back moves the wall clock, not your body clock, so the extra hour often turns into an early wake instead. Morning light, a steady wake time and a little patience help most people settle within a week, and gradual shifts help babies follow along. Mendtide’s morning briefing reads your Apple Health sleep data, so you can watch your nights settle back into their rhythm in the days after the change.
Your body keeps time by the sun, not by the clock on the wall. Give it a few mornings of light, and it will catch up.