screen time and sleep: what the research actually shows

A 2025 study from University College London tracked 1,200 adults and found that those who used phones or tablets within one hour of bedtime took an average 34 minutes longer to fall asleep than those who avoided screens.

Device use has risen sharply in the capital since hybrid work patterns settled after 2023, with many residents checking emails or streaming shows late into the night. Poor sleep now links directly to higher NHS GP visits for fatigue-related issues across boroughs, where waiting times for mental health support already stretch into weeks.

Walkers finishing Parkrun sessions in Hyde Park often head straight to phones on the Tube ride home, while residents near Regent's Park report similar habits after cycling superhighway commutes from the east. Local NHS wellbeing programmes in these areas have begun adding short evening workshops on device habits to existing mental health drop-ins.

Blue light effects on melatonin

Research published in the Journal of Sleep Research in March 2025 measured melatonin levels in participants exposed to typical phone brightness for 30 minutes before bed. Levels dropped by 23 percent compared with control groups, with effects strongest in people over 35 who live in high-density postcodes such as EC1 and SE1.

London's 24-hour culture amplifies the pattern, yet simple filters and timed shut-offs cut the delay in sleep onset by half in follow-up trials run by the same UCL team.

Steps that fit daily routines

Setting device night modes by 9pm and replacing the final scroll with a 10-minute loop around local green space produced the clearest gains in the UCL data. NHS apps already used by thousands of London patients include built-in reminders that link directly to these findings, and several GP surgeries in Camden now print quick-reference cards with the same advice at check-in desks.

Residents who tested the approach for four weeks reported waking 22 minutes earlier on average without extra alarm reliance, according to the study logs. Checking in with a local NHS wellbeing coach or GP remains the first step for anyone whose sleep issues persist beyond a fortnight.