Clocks Going Back: How to Adjust Your Sleep for Shorter Days

In the UK the clocks go back by one hour in late October, which means the evenings suddenly turn dark much earlier (and you lose an hour of evening daylight). For many people that shift - combined with more time spent indoors in the evening - makes it harder to fall asleep and wake up at the right time for a few days.

This guide explains why the clock change can disturb sleep and what the NHS and the US National Institutes of Health (NIH) recommend for getting your body clock back into a comfortable rhythm. It is general information, not medical advice - if poor or persistent sleep is affecting your everyday life, see a GP.

Why the clock change can disrupt sleep

Your body follows an internal body clock that runs on roughly a 24-hour day-night cycle. The NIH explains that bright light can help signal to the body that it is time to be awake, and that staying up late or sleeping in late can disrupt the body clock’s sleep-wake rhythm.

When the clocks change by an hour, your routine shifts against your body clock at the same time as the evenings get darker much earlier. Add in the tendency to spend more evenings indoors, under artificial light rather than natural daylight, and it’s easy for your sleep-wake rhythm to drift out of step with your schedule.

Source: US National Institutes of Health, NHLBI - Healthy Sleep Habits.

How to adjust: habits that help

The same habit-based guidance the NHS and NIH give for good sleep in general is exactly what works when the clocks change. The key is to help your body clock stay anchored to a steady routine.

1. Keep a consistent wake-up time

Both the NHS and NIH put a fixed wake-up time at the heart of good sleep. The NHS advice is to wake up and get out of bed at the same time every day, and the NIH recommends going to bed and waking at the same time every day, keeping weekday and weekend wake times close together.

In practice: after the clocks go back, set your alarm for your normal time in the new hours and get up when it rings - don’t grab an extra hour’s lie-in and let the routine drift.

Source: NHS - Insomnia; US National Institutes of Health, NHLBI - Healthy Sleep Habits.

2. Get daylight and time outside during the day

The NIH advises you to spend time outside every day when possible and stay physically active - time spent in daylight helps keep the body clock anchored to the day. After the clocks change, the daylight window for many people shifts, so a short walk or some time outdoors in daylight within your normal day helps anchor the rhythm.

Source: US National Institutes of Health, NHLBI - Healthy Sleep Habits.

3. Wind down properly in the hour before bed

The NHS recommends you relax for at least one hour before bed - for example, taking a bath or reading a book. The NIH adds that the hour before bed should be quiet time, avoiding intense exercise and bright artificial light, such as from a TV or computer screen, because light can signal to the brain that it’s time to be awake.

Source: NHS - Insomnia; US National Institutes of Health, NHLBI - Healthy Sleep Habits.

4. Dim the light in the evening and avoid bright screens

With evenings getting darker earlier, some people naturally dim the lights - which is helpful. The NHS specifically advises not watching TV or using devices like smartphones right before bed, and the NIH highlights that bright artificial light near bedtime can keep the brain feeling awake. Keeping the bedroom dark and quiet also supports sleep.

Source: NHS - Insomnia; US National Institutes of Health, NHLBI - Healthy Sleep Habits.

5. Watch caffeine in the late afternoon

The NIH notes caffeine’s effects can last up to 8 hours, so a coffee in the late afternoon can make it harder to fall asleep at night. The NHS recommends not drinking tea or coffee for at least 6 hours before bed. On a shorter, darker evening the temptation for an afternoon pick-me-up can grow - but it can undo your wind-down.

Source: US National Institutes of Health, NHLBI - Healthy Sleep Habits; NHS - Insomnia.

How long does it take to adjust?

There is no official figure for how long adjustment takes. Holding a consistent wake time and getting daylight each day generally helps your rhythm settle - a steady routine over a week or two is a reasonable goal rather than expecting an instant fix. If you keep a consistent routine and still have trouble sleeping, the NHS says the next step is to seek advice.

When to seek help

The NHS says to see a GP if:

• changing your sleeping habits has not helped
• you have had trouble sleeping for months
• your insomnia is affecting your daily life in a way that makes it hard to cope

A GP can look for what’s causing the problem and, where appropriate, recommend support such as cognitive behavioural therapy (CBT) rather than relying on sleeping pills.

Source: NHS - Insomnia.

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Sources

• NHS - Insomnia (consistent wake time; relax 1 hour before bed; dark and quiet bedroom; no screens right before bed; no tea/coffee at least 6 hours before bed; when to see a GP): https://www.nhs.uk/conditions/insomnia/
• US National Institutes of Health, NHLBI - Healthy Sleep Habits (body clock and light; awake at the same time every day; spend time outside; bright light can signal the brain to be awake; caffeine effects can last up to 8 hours): https://www.nhlbi.nih.gov/health/sleep-deprivation/healthy-sleep-habits

This article is for general information and is not a substitute for professional medical advice.