People around the world will likely lose 50 to 58 hours of sleep a year by 2099 due to global warming, a new study has revealed.
The researchers used wristbands with built-in accelerometers to measure sleep duration and sleep time in more than 47,000 adults in 68 countries, for an average of six months, for a study published in the journal One Earth.
Adults should get seven to nine hours of sleep, according to the US National Sleep Foundation. The likelihood of getting less than seven hours of sleep increases by 3.5% if nighttime minimum outside temperatures exceed 25°C compared to an initial temperature of 5 to 10°C, the study found.
“The 3.5% sleep loss may initially seem like a small number, but it increases,” said Alex Agostini, a professor in the department of justice and society at the University of South Australia in Adelaide. She did not participate in the study.
When adults don’t get the recommended amount of sleep, they can have trouble concentrating, Alex said. Long-term effects may include an increased risk of some health problems, such as cardiovascular and gastrointestinal disease, she said.
“Many of us turn all night at some point in our lives – imagine doing that eight times. How would you feel?” Alex said.
A single night above 30°C reduces sleep time by about a quarter of an hour per person, said lead study author Kelton Minor, a doctoral candidate at the Center for Social Data Science at the University of Copenhagen.
However, seniors lost twice the amount of sleep per degree of warming compared to young or middle-aged adults. In addition, sleep loss was three times higher for seniors in low-income areas compared to high-income areas, he said. Women were also about 25% more affected by rising temperatures than men, Minor added.
Low chance of adapting to heat
The researchers also found evidence that people living in warmer climates lose more sleep per degree compared to those in colder climates, and that people adapt better in colder climates than in warmer climates. This greater loss of sleep in warmer places suggests that people cannot easily adapt to warmer temperatures, Minor said.
As temperatures continue to rise due to global warming, Minor projected that sleep loss will increase at a faster rate in regions that already experience hot climates compared to those that do not.
People didn’t seem to adjust to heat either: The amount of sleep people got in the first month of summer, when people were least familiar with heat, and in the last month of summer, when they were most familiar with it, showed who lost nearly the same amount of sleep, according to Minor.
This similarity in sleep loss indicated that people may not adapt to higher temperatures over time, he said. What’s more, the results showed that people didn’t seem to catch up on sleep lost during a warm night in the two weeks after a spike in temperature, the researcher said.
The cost of warmer temperatures
Humans spend about a third of their lives sleeping, but an increasing number of people don’t get enough sleep, Minor said. A third of adults in the United States report that they typically sleep less than the recommended seven to nine hours, according to the US Centers for Disease Control and Prevention (CDC).
“Many of us already don’t get enough sleep, and the contribution of relevant sleep problems to global warming could have real consequences for our health and well-being,” Alex said by email.
When humans begin to sleep, their core body temperature drops, she said. When the ambient temperature is warmer, it becomes more difficult to cool down, which can affect the ability to fall asleep, she explained.
Air conditioning can allow people to adapt to warmer temperatures, but it’s not a reliable long-term solution, Alex said.
People living in low-income countries have less access to air conditioning, which can widen the equality divide, Minor said.
In addition, air conditioners release greenhouse gas emissions, which naturally increase global warming, Alex said.
“The biggest and best solution to the problem is using eco-friendly building planning and implementing other changes to improve the issue of global warming,” she said.
Source: CNN Brasil