Climate change negatively impacting human sleep

Increasing ambient temperatures negatively impact human sleep around the globe, according to a study.

The research, published recently in the journal One Earth, suggests that by the year 2099, suboptimal temperatures may erode 50 to 58 hours of sleep per person per year. The researchers also found that the effect of temperature on sleep loss is substantially larger for residents from lower income countries as well as in older adults and females.

"Our results indicate that sleep - an essential restorative process integral for human health and productivity -- may be degraded by warmer temperatures," said study first author Kelton Minor of the University of Copenhagen in Denmark. "In order to make informed climate policy decisions moving forward, we need to better account for the full spectrum of plausible future climate impacts extending from today's societal greenhouse gas emissions choices," Minor said.

It's long been known that hot days increase deaths and hospitalisations and worsen human performance, yet the biological and behavioral mechanisms underlying these impacts have not been well understood, the researchers said. "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," he explained. The researchers used anonymised global sleep data collected from accelerometer-based sleep-tracking wristbands. The data included 7 million nightly sleep records from more than 47,000 adults across 68 countries spanning all continents except for Antarctica. Measures from the type of wristbands used in this study had previously been shown to align with independent measures of wakefulness and sleep.