When we think of climate change we think of a warming planet and the physical risks that accompany it such as hurricanes, droughts, and sea-level rises. But there are other ways that the heating up of the planet can affect us and they may just be as severe.
50 to 58 hours of sleep per person per year will be lost by 2099
The researchers estimate that by the year 2099, increased temperatures may erode 50 to 58 hours of sleep per person per year. This effect would be even worse for residents from lower-income countries as well as for 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 the lead author of the study Kelton Minor, in the statement. “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.”
It's a long-known fact that increased temperatures lead to more deaths and hospitalizations but what has not been clarified is what exact impact it has on people's ability to rest properly.
“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 new research examined global sleep data collected from accelerometer-based sleep-tracking wristbands from more than 47,000 adults across 68 countries spanning all continents except for Antarctica. The researchers found that on nights that were considered very hot (greater than 30 degrees Celsius, or 86 degrees Fahrenheit), sleep declined an average of just over 14 minutes.
“Our bodies are highly adapted to maintain a stable core body temperature, something that our lives depend on,” Minor says. “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 alignment with previous research
The findings were in alignment with early studies done on mice and humans that found that quality and quantity of sleep did indeed decrease as the heat increased.
“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 concluded.
Perhaps the most troubling finding of the new study was that sleep loss was higher for people in developing countries meaning it is affecting the most vulnerable populations the most.
The study is published in the journal One Earth.
Ambient temperatures are rising worldwide, with the greatest increases recorded at night. Concurrently, the prevalence of insufficient sleep is rising in many populations. Yet it remains unclear whether warmer-than-average temperatures causally impact objective measures of sleep globally. Here, we link billions of repeated sleep measurements from sleep-tracking wristbands comprising over 7 million sleep records (n = 47,628) across 68 countries to local daily meteorological data. Controlling for individual, seasonal, and time-varying confounds, increased temperature shortens sleep primarily through delayed onset, increasing the probability of insufficient sleep. The temperature effect on sleep loss is substantially larger for residents from lower-income countries and older adults, and females are affected more than males. Those in hotter regions experience comparably more sleep loss per degree of warming, suggesting limited adaptation. By 2099, suboptimal temperatures may erode 50–58 h of sleep per person-year, with climate change producing geographic inequalities that scale with future emissions.