Climate change will deprive us of sleep, study says
is already expected to start wildfires and melt glaciers but a new study claims it will also deprive us of our beloved night's rest. Researchers have studied global weather data and information from sleep trackers worn by the public to predict future effects on our sleep. By the year 2099, temperatures will have taken away somewhere between 50 to 58 hours of sleep per person per year just under 10 minutes per night. Temperature effects on sleep loss will be substantially larger for residents from lower income countries, such as , as well as for older adults and females, according to the study. Overall, adults will fall asleep later, rise earlier, and sleep less during hot nights in the future, which will risk 'several adverse physical and mental outcomes'. Higher global temperatures will eat away at our sleep totals because the body's core temperature needs to drop to fall asleep. This becomes harder to achieve as temperatures in our surroundings get hotter and hotter, however. 'Our bodies are highly adapted to maintain a stable core body temperature, something that our lives depend on,' said study author Kelton Minor at the University of Copenhagen, Denmark. 'Yet every night they do something remarkable without most of us consciously knowing they shed heat from our core into the surrounding environment by dilating our blood vessels and increasing blood flow to our hands and feet.' In order for our bodies to transfer heat from these extremities, the surrounding environment needs to be cooler than we are, Minor said. For the study, the research team The data included 7 million nightly sleep records from more than 47,000 adults across 68 countries spanning all continents except for Antarctica, including the UK, the US, Australia, France, India, Mexico and Canada. This was then compared with global weather measurements over time, allowing the team to find patterns between the two factors and make predictions for the future. The study found that on very warm nights hotter than 86F (30C), sleep declines an average of just over 14 minutes. The likelihood of getting less than seven hours of sleep also increases as temperatures rise. Under normal living routines, people appear far better at adapting to colder outside temperatures than hotter conditions. 'Across seasons, demographics, and different climate contexts, warmer outside temperatures consistently erode sleep, with the amount of sleep loss progressively increasing as temperatures become hotter,' Minor said. One important observation was that people in developing countries seem to be more affected by these changes. However, a limitation of the study is it did not account for artificial cooling technologies such as air conditioning. It's possible that the greater prevalence of air conditioning in developed countries played a role in the results. Also, there was a lack of sleep tracking data from Africa, which experiences particularly severe heat compared to other parts of the world. Future research should consider more vulnerable populations, particularly those residing in the world's hottest and historically poorest regions, the experts say. Recent self-reported data from the US have suggested that subjective sleep quality decreases during periods of hot weather. But how temperature fluctuations may impact changes in objective sleep outcomes in people living across a variety of global climates had been unclear. 'In this study, we provide the first planetary-scale evidence that warmer-than-average temperatures erode human sleep,' Minor said. 'We show that this erosion occurs primarily by delaying when people fall asleep and by advancing when they wake up during hot weather.' The study has been published today in the journal .