Brits are set to move their clocks forward by one hour at 1am on Sunday 29th March 2026, marking the start of British Summer Time. The shift from Greenwich Mean Time brings lighter evenings but reduces sleep by an hour, which can disrupt daily routines.
Experts warn that this change can trigger a “72-hour sleep danger zone” as the body adjusts its internal clock.
Dr Deborah Lee, a GP from Dr Fox Online Pharmacy, explains the impact in collaboration with Cult Beauty. “Even a one-hour change can throw off your internal body clock. For many people, it can take up to 72 hours to fully adjust, during which time you may feel more tired, less focused, and out of sync,” she says.
The disruption is similar to mild jet lag, caused by a mismatch between the body’s natural rhythm and external cues such as daylight. Research on daylight saving transitions shows the spring change can reduce sleep duration, increase sleep fragmentation, and lead to greater daytime sleepiness, especially among evening chronotypes.
Effects during the 72-hour adjustment period
During this period, people may experience lower energy levels as reduced sleep leads to fatigue. Concentration and productivity can decline due to impaired cognitive function, while mood may also be affected, with some experiencing irritability or low mood. Poor-quality rest can additionally impact physical appearance, with skin appearing dull or more tired.
How to reset your sleep routine
Dr Lee recommends several steps to help the body adjust more quickly
Start adjusting early
Go to bed 15–20 minutes earlier in the days leading up to the change. Get outside in the morning to expose yourself to natural light and help regulate your internal clock.
Keep a consistent schedule
Maintain regular sleep and wake times, including weekends. Avoid lie-ins, which can delay adjustment.
Optimise your sleep environment
Keep your bedroom at around 18°C. Adjust bedding or heating to stay comfortable and avoid sleep disruption.
Create a wind-down routine
Avoid screens for two hours before bed. Try relaxing activities such as reading or journaling. A warm bath or shower can help signal that it is time to sleep. Wearing cotton sleepwear and socks may also support temperature regulation.
Support overall well-being
If you experience low energy or mood, consider supplements such as vitamin D and magnesium. Sleep aids like pillow sprays or weighted blankets may also help relaxation.
Health guidance highlights the importance of morning light exposure and consistent routines in helping the body adapt. Avoiding naps can also speed up recovery. While adjustment times vary, many people return to normal within a few days.