Withings data reveals one of the biggest sleep disruptions recorded across major UK cities in 2026 during the June heatwave with Londoners suffering the most versus other major cities.
Londoners lost a staggering 35 minutes of sleep on the hottest nights of the June heatwave (24-26th June), when temperatures soared up to approximately 33°C, with a sleep loss recorded of up to 37 minutes on 24th June.

Other major cities across the UK were affected with people in Manchester suffering the sharpest day-to-day decline in sleep with 32 to 36 minutes less sleep on 24th-26th June.

People in Birmingham proved the most resilient in the UK despite the heat with peak sleep losses of 28-30 minutes on average during the peak nights of the June heatwave, a lot less than the larger cities.

The research also reveals the heatwave’s impact on activity levels across Britain suggesting that people adapted by staying indoors and sedentary. People based in Manchester proved to be the most sedentary with 836 less steps recorded on the 24th June versus the 713 less steps taken by Londoners on exactly the same day.

Eric Carreel, Chairman, Co-founder & CEO of Withings: “Sleep is one of the clearest indicators of our overall health, yet it’s also one of the first things to be disrupted by changes in our environment. Our data shows that heatwaves can have a measurable impact on how long people sleep, particularly in densely populated urban areas. While sleep loss during a heatwave may seem insignificant on a single night, repeated sleep disruption can affect recovery, cognitive performance, cardiovascular health and overall wellbeing.”

Simple steps for the next heatwave

Withings suggests three habits to manage the next heatwave:
Keep hydration steady across the day (not just during exercise)
Move activity to before 10am or after 6pm when temperatures ease, and ventilate bedrooms in the early morning before the outside air warms up.
Keep an eye on their own activity, sleep, and heart-rate trends with connected health products through the summer months, often the clearest way to catch heat-related strain before it builds up.