An Overlooked Consequence of Global Warming: Insomnia – Mother Jones
Rising temperatures driven by the climate crisis are reducing people’s sleep across the world, according to the largest study to date.
Good sleep is essential for health and well-being. But global warming is increase in nighttime temperatures, even faster than during the day, which makes it more difficult to sleep. The analysis found that the average global citizen already loses 44 hours of sleep per year, resulting in 11 nights with less than seven hours of sleep, a standard benchmark for adequate sleep.
Sleep loss will increase further as the planet continues to heat but it affects some groups much more than others. Sleep loss per degree of warming is about a quarter higher for women than for men, twice as high for people over 65 and three times higher for those in less affluent countries. The researchers used data from sleep tracking bracelets used by 47,000 people for 7 million nights and in 68 countries.
Previous studies have shown that rising temperatures harm health, including increasing heart attacks, suicides and mental health crisisand accidents and injuries, as well as reduced work capacity.
Poor sleep has also been shown to have these effects, and the researchers said their study suggests sleep disturbances may be a key mechanism by which heat causes these health effects. Worryingly, the researchers said, their data showed no signs of people’s ability to adapt to warmer nights.
“For most of us, sleep is a very familiar part of our daily routine; we spend nearly a third of our lives sleeping,” said Kelton Minor, of the University of Copenhagen, Denmark, who led the research. “But a growing number of people in many countries around the world are not getting enough sleep.”
“In this study, we provide the first evidence on a planetary scale that warmer than average temperatures erode human sleep,” he said. “That could actually be the tip of the iceberg, as our estimates are very likely to be conservative.”
Minor said reduced sleep from warmer nights affects huge populations. For example, he said, a night above 25°C (77°F) in a city of a million people would result in an additional 46,000 people suffering from shorter sleep. “And if you look at the heat wave that sweats currently in India and Pakistanwe’re talking about billions of individuals exposed to conditions that could lead to significant sleep loss,” Minor said.
The study, published in the journal A land, analyzed 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 freshen up every night while they fall asleep, but it’s more difficult when it’s warmer.
Women may be more affected because their bodies generally cool down faster than men’s when they fall asleep. Women also have higher levels of subcutaneous fat on average, which slows cooling. It is known that older people sleep less at night and have poorer body temperature regulation, which may explain their susceptibility. People in poorer countries could lose more sleep because they have less access to cooling features such as shutters, fans and air conditioning.
The researchers found that the impact of warmer nights on sleep was observed in all countries, whether they had naturally cooler or warmer climates, with a clear impact when nighttime temperatures exceeded 10°C (50°C). F).
“Worryingly, we also found evidence that people already living in warmer climates experience greater sleep erosion per degree increase in temperature,” Minor said. “We expected these individuals to be better suited.” Also, people didn’t catch up on missed sleep at later times, the data shows.
Minor said the research had important implications for policy makers, who needed to ensure cities, towns and buildings were well adapted to heat in order to reduce the health effects of rising temperatures. Official UK government advisers warned in 2021 that it was failing to protect people from rapidly increasing risks of the climate crisis, particularly heat waves.
The data used in the study came mainly from wealthier countries, although it included some from India, China, Colombia and South Africa. Bracelets also tended to be worn by people less prone to sleep disturbances in warmer temperatures, such as middle-aged and wealthier men.
“Lower income people are underrepresented in the data and we’re very transparent about that,” Minor said. He said more research was needed, especially in places already ranked among the hottest in the world, such as large parts of Africa, Central America and the Middle East. The research was unable to assess sleep quality, such as the different stages of sleep, but there was no change in the number of times people woke up during the night.
Minor said the path the world takes in terms of the planet’s temperature will have consequences for everyone’s sleep. “Our decisions, collectively as societies, will have costs in terms of sleep.”