The rise in hotter nights is cutting our sleep and harming the health of millions

Rising temperatures driven by the climate crisis are cutting the sleep of people across the world, the largest study to date has found.

- Damian Carrington

Good sleep is critical to health and wellbeing. But global heating is increasing night-time temperatures , even faster than in the day, making it harder to sleep. The analysis revealed that the average global citizen is already losing 44 hours of sleep a year, leading to 11 nights with fewer than seven hours of sleep, a standard benchmark of sufficient sleep.

Lost sleep will increase further as the planet continues to heat , but it affects some groups much more than others. The sleep loss per degree of warming is about a quarter higher for women than men, twice as high for those over 65 years old and three times higher for those in less affluent nations. The researchers used data from sleep-tracking wristbands used by 47,000 people over 7m nights and across 68 countries.

Previous studies have shown that rising temperatures damage health, including increas ing heart attacks, suicides and mental health crises , and accidents and injuries, as well as reducing the ability to work. Poor sleep has also been shown to have these effects, and the researchers say their new study suggest s that disturbed sleep may be a key mechanism by which heat causes these health impacts. The researchers say their data show s no signs of people being able to adapt to hotter nights.