People are literally losing sleep over climate change 

People are literally losing sleep over climate change 

Rising temperatures driven by the climate crisis are affecting the sleep patterns of people across the world.  Picture: Alamy/PA

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

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 less than seven hours’ 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 seven million nights and across 68 countries.

Previous studies have shown that rising temperatures damage health, including increased heart attacks, suicides and mental health crises, and accidents and injuries, as well as reducing the ability to work.

Health impact

Poor sleep has also been shown to have these effects and the researchers said their study suggests that disturbed sleep may be a key mechanism by which heat causes these health impacts. Worryingly, the researchers said, their data showed no signs of people being able to adapt to hotter nights.

A protest by Extinction Rebellion outside City Hall in Limerick Friday where hundreds of pairs of shoes were placed out front to represent young people and children as they called on national and local authorities to respond to the Climate Crisis with the same urgency as the Covid Crisis. Picture: Damien Storan.
A protest by Extinction Rebellion outside City Hall in Limerick Friday where hundreds of pairs of shoes were placed out front to represent young people and children as they called on national and local authorities to respond to the Climate Crisis with the same urgency as the Covid Crisis. Picture: Damien Storan.

“For most of us, sleep is a very familiar part of our daily routine; we spend nearly a third of our lives asleep,” said Kelton Minor, at the University of Copenhagen, Denmark, and who led the research. “But growing numbers of people in many countries around the world do not sleep enough. 

“In this study, we provide the first planetary-scale evidence that warmer than average temperatures erode human sleep. It might actually be the tip of the iceberg, because it’s very likely our estimates are conservative.” 

 Minor said sleep reduced by warmer nights is affecting huge populations. For example, he said, a night above 25C in a city of a million people would result in 46,000 extra people suffering from shorter sleep. 

“And if you look at the heatwave that’s transpiring right now in India and Pakistan , we’re talking about billions of individuals exposed to conditions expected to result in considerable sleep loss,” Minor said.

The study, published in the journal One Earth, analysed sleep and outdoor weather data collected from 2015 to 2017 and found that higher temperatures reduced sleep by delaying its onset. People’s bodies need to cool every night as they fall asleep, but this is harder when it is warmer.

Affected

Women may be affected more because their bodies usually cool faster than men’s when going to sleep. Women also have higher levels of subcutaneous fat on average, making cooling slower. Older people are known to sleep less at night and have poorer body temperature regulation, which may explain their susceptibility. People in poorer nations could lose more sleep as they have less access to cooling features such as window shutters, fans and air conditioning.

The researchers found the impact of warmer nights on sleep was seen in all countries, whether they had naturally cooler or warmer climates, with the impact clear when night-time temperatures rose above 10C.

“Worryingly, we also found evidence that people already living in warmer climates experienced greater sleep erosion per degree of temperature rise,” said Minor. “We had expected those individuals to be better adapted.” Furthermore, people did not catch up on missed sleep at later times, according to the data.

  • Guardian

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