British Summer Time begins at 1am on Sunday 29th March 2026, when clocks across the UK move forward one hour to 2am. The annual change brings lighter evenings and longer daylight hours but also means most people lose an hour of sleep overnight.
The transition from Greenwich Mean Time to British Summer Time can disrupt the body’s internal clock, known as the circadian rhythm. As the body adjusts to the new schedule, people may temporarily experience difficulty falling asleep, staying asleep, or feeling fully rested.
Dr Tim Mercer, an NHS GP partner and GP trainer collaborating with Opera Beds, said the time change can unsettle established sleep routines.
“As the clocks go forward and we move into British Summer Time, we lose an hour of sleep, which can upset our internal body clock. If you have a good sleep routine, you may consider moving it forward by 10–15 minutes in the days leading up to the change.”
Dr Mercer explained that light exposure plays an important role in regulating sleep through the hormone melatonin. “Melatonin plays a key role in regulating our sleep-wake cycle and is a hormone naturally produced in the brain, and its release is influenced by light exposure. Exposure to morning daylight suppresses melatonin production, waking us up and keeping us alert during the day. During the evening and in darkness, melatonin production increases, signalling to your body that it’s time to sleep.”
Dr Mercer added that the later sunset following the clock change can delay this process. “With the later onset of darkness after the clocks go forward, your body may delay melatonin production, potentially making it harder to fall asleep at your usual time. This shift can lead to temporary disruptions in sleep patterns as your body adjusts to the new schedule.”
Research suggests the spring clock change can lead to short-term sleep loss and fatigue. Some studies have also linked the transition to temporary increases in health risks, including a higher likelihood of cardiovascular events in the days immediately after the change.
Studies also indicate that the shift can affect sleep duration and quality, particularly among people with evening chronotypes, who may find it harder to adjust to an earlier bedtime.
Tips to adjust to the time change
Dr Mercer and Opera Beds recommend several steps to help the body adapt more easily:
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Gradual adjustments: In the days before the time change, shift your bedtime and wake-up time by 10–15 minutes earlier each day to help ease your body into the new schedule.
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Morning light exposure: Spending time outdoors in early daylight can help reset the circadian rhythm. Natural light is one of the strongest signals that regulates the body clock.
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Limit late meals: On Sunday 29th March, try eating dinner an hour earlier than usual. Finishing meals several hours before bedtime can help prevent indigestion and sleep disruption.
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Stay active: Longer daylight hours offer more opportunities for outdoor activity, which can support better sleep. However, vigorous exercise close to bedtime may be stimulating.
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Maintain good sleep hygiene: A sleep-friendly environment includes controlling lighting, sound, and temperature. Experts suggest an ideal bedroom temperature of around 16–18°C, with a darker, cooler and quieter space to promote uninterrupted rest.
Most people adjust within a few days to a week as their bodies adapt to the new schedule. British Summer Time will remain in effect until clocks return to Greenwich Mean Time on 25th October 2026.