Key Takeaways
- The clocks go back at 2am on Sunday 25 October, and your body clock, which runs on light, takes a few days to catch up.
- Less evening daylight can flatten energy and mood, but brighter mornings give you a natural chance to reset.
- Get 10 to 20 minutes of outdoor light within an hour of waking, and keep your sleep and wake times steady, weekends included.
- Move earlier in the day and give yourself a 30 to 60 minute screen-free wind-down before bed.
When the clocks go back in autumn, your internal body clock, which is set by light rather than by clock time, takes a few days to catch up, which can affect sleep, energy, appetite and mood. The simplest ways to adjust are to get outdoor daylight within an hour of waking, keep the same bedtime and wake time every day, move earlier in the day while it is light, and dim screens and lighting for 30 to 60 minutes before bed. In the UK, the clocks go back one hour at 2am on the last Sunday of October, which is 25 October in 2026.
At 2am this Sunday, 25 October, the clocks go back an hour. Most of us file it under “bonus lie-in” and move on. But your body keeps its own time, and it doesn’t read the clock on your phone.
With a few simple, science-backed habits, you can turn the switch to GMT into a genuine reset rather than a week of feeling slightly off. Here’s what’s really going on, and how to make it work for you.
What the clock change does to your body
Your internal clock gets out of sync. Deep in your brain, a master clock sets the rhythm for sleep, alertness, hormones and even digestion. It runs on light, not on clock time. When the clocks jump overnight, there’s a gap between that time on the clock and your body time. That’s why you might wake before your alarm, feel hungry at odd times or hit an afternoon slump. Elite teams plan for exactly this when athletes cross time zones; the clock change is a mini version of jet lag.
Your mood and energy shift. Less daylight affects two key chemical messengers. Serotonin, linked to mood and focus, tends to dip with less light. Melatonin, the hormone that signals “time for sleep”, starts flowing earlier as darkness arrives sooner. The result can feel like flat energy and an urge to hibernate.
Your evenings shrink. Darker evenings make it tempting to skip the after-work walk, cancel plans and stay in. Less movement and less social contact are two of the quickest ways to drag mood and sleep quality down over winter.
The surprising good news
Here’s a twist. A large study published in The BMJ in December 2025 looked at the health records of more than 680,000 people in England between 2008 and 2019. In the week after the autumn clock change, GP and hospital records showed slightly fewer cases of anxiety (down 3%), depression (down 4%) and sleep disorders (down 8%), plus a small dip in heart-related events.
The researchers think morning light is a big part of the reason. After the clocks go back, more of us get daylight early in the day, which is exactly when it does most to reset the body clock. Interestingly, they note we only gain around half an hour of extra sleep, so it isn’t just the lie-in doing the work.
Your takeaway here is that this week is an opportunity. Use that brighter morning well and you’re working with your biology, not against it.
Four ways to protect your wellbeing
1. Chase the morning light
Light is the most powerful signal your body clock has. Aim for 10–20 minutes outside within an hour of waking. A walk to the shop, coffee on the doorstep or a lap of the block all count. Even on a grey morning, outdoor light is far brighter and more beneficial than indoor lighting.
2. Keep your routine steady
Go to bed and get up at the same time every day, weekends included. Consistency is how athletes protect sleep in a heavy training block, and it’s the fastest way to settle after the switch. If you tend to wake early during the first week, shift your bedtime later by 10–15 minutes a night rather than all at once.
3. Move in the daylight
Exercise boosts energy, lifts mood and deepens sleep. With evenings getting darker, try moving your activity earlier, a lunchtime walk, a morning session or an active commute. If you train hard, recovery matters more when sleep is shifting. Some people add tart Montmorency cherry, which naturally contains melatonin and has been studied for sleep quality. You’ll find CherryActive in the PEAK4 shop.
4. Dim the screens before bed
Bright, blue-heavy light from phones and laptops tells your brain it’s still daytime and holds back melatonin. Give yourself a 30–60 minute wind-down with dim, warm lighting. Swap scrolling for a book, a stretch or a caffeine-free brew, such as the Rest blend from Mission Tea.
Treat the clock change like a small time-zone shift: get light early, hold your routine and let your body catch up, rather than relying on the extra hour in bed. The PEAK4 expert team
Your clock-change checklist
Save this, screenshot it or stick it on the fridge.
- Saturday night: go to bed at your usual time and let the extra hour be a bonus, not a late night.
- Sunday morning: get outside for 15 minutes of daylight before 10am.
- Keep your wake-up time the same all week, weekend included.
- Book one daytime workout or walk into your diary for each weekday.
- Plan one social catch-up this week so dark evenings don’t become lonely ones.
- Set a phone wind-down reminder 45 minutes before bed.
- Cut caffeine after 2pm while your body clock settles.
- Start a daily vitamin D supplement: the NHS advises 10 micrograms a day from October to March.
- Notice how you feel by Friday: energy, mood and sleep. Small wins count.
Make this winter your reset
The clocks going back doesn’t have to mean a slow slide into winter. Treat this week like a pre-season, protect your sleep, get light early, keep moving and stay connected. Your body will thank you well into spring.
If you’re after a little extra support, browse our science-backed recovery and sleep essentials.
This article is general wellbeing information, not medical advice. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. Always follow the directions on the label and do not exceed the recommended daily intake. If you are pregnant, breastfeeding, taking medication or have a medical condition, speak to your GP or pharmacist before taking a supplement. If low mood or poor sleep lasts more than a couple of weeks, speak to your GP.
Sources
- de Lange MA et al. Acute effects of daylight saving time clock changes on mental and physical health in England. The BMJ, 2025.
- Howatson G et al. Effect of tart cherry juice on melatonin levels and enhanced sleep quality. European Journal of Nutrition, 2012.
- NHS. Vitamin D.
Frequently Asked Questions
When do the clocks go back in 2026?
In the UK, the clocks go back one hour at 2am on Sunday 25 October 2026, moving from British Summer Time (BST) to Greenwich Mean Time (GMT). They go forward again on the last Sunday in March.
How long does it take to adjust to the clocks going back?
Most people settle within a few days to a week. Getting daylight early in the day and keeping the same sleep and wake times, weekends included, helps your body clock catch up faster.
Do you really get an extra hour of sleep when the clocks go back?
Not quite. The authors of a 2025 BMJ study note that people gain only around half an hour of extra sleep on average, so how you use the brighter mornings matters more than the lie-in.
Why do I feel tired after the clocks go back?
Your body clock runs on light, not on the time on your phone, so for a few days there is a gap between clock time and body time. Darker evenings also bring the evening rise in melatonin, the hormone that signals sleep, forward, so you may feel sleepy earlier.
Should I take vitamin D in autumn and winter?
The NHS advises adults and children over 4 to consider taking a daily vitamin D supplement of 10 micrograms from October to March, when sunlight is not strong enough for the body to make enough.
Do I need supplements to adjust to the clock change?
No. Daylight, a steady routine, daytime movement and a proper wind-down do the heavy lifting. Supplements and caffeine-free drinks are optional extras, never a substitute for a varied, balanced diet and a healthy lifestyle. If you want to explore them, the PEAK4 expert team curates the Recover range.
