screen time and sleep: what the research actually shows

A June 2026 University College London analysis of 2,400 adults found that screen use within 60 minutes of bedtime cuts average sleep by 42 minutes per night.

The pattern matters now because hybrid work has pushed many residents to scroll later in the evenings while daylight lingers past 9pm in July. NHS data shows one in three Londoners already report sleep problems, and the added screen exposure compounds existing pressures on the capital’s mental health services.

Local habits under the microscope

Walkers finishing Parkrun sessions at Clapham Common often check phones on the way home along Venn Street, extending blue-light exposure right up to bedtime. In Hyde Park, Royal Parks staff have noted rising numbers of visitors lingering after dusk with tablets and laptops near the Serpentine, habits that clash with NHS GP guidance on wind-down routines issued last year.

The UCL team measured melatonin levels and found a 23 per cent drop after just 45 minutes of phone or tablet light at 10pm. Participants living within two miles of central London reported an extra 18 minutes of screen time compared with outer-borough residents, linked to longer commutes on cycling superhighways and later dinners.

Steps residents can take tonight

Switching devices to night mode by 9pm and leaving phones outside the bedroom cuts the melatonin suppression in half, according to the same study. Local GPs at practices along Harley Street now hand out free NHS sleep packs that include simple timers for screens, while community groups at Regent’s Park run weekly workshops on replacing late scrolling with short evening walks along the Broad Walk.

Residents who tested the changes for two weeks gained an average of 31 minutes of sleep and reported steadier morning energy. The findings arrive as the NHS prepares to expand its digital sleep tool to all London boroughs by September.