New research has suggested that higher temperatures might lead to nearly 60 hours of lost sleep per person every single year.

In addition to the lost sleep, researchers estimated that by the beginning of the 21st century, temperatures have already caused a loss of 44 hours of sleep due to suboptimal nighttime temperatures.

"For most of us, sleep is a very familiar part of our daily routine; we spend nearly a third of our lives asleep. In this study, we provide the first planetary-scale evidence that warmer than average temperatures erode human sleep," says Kelton Minor, the lead author of the study and a researcher at the University of Copenhagen

Researchers used sleep-tracking wristbands and a smartphone app, collecting sleep data from over 47,000 adults in 68 countries. Then they mapped that data on to local daily meteorological data. 

They learned that sleep loss and the risk of insufficient sleep increased when temperatures rose above 50 degrees Fahrenheit (10 degrees Celsius). On warm nights—above 86 degrees Fahrenheit (30 degrees Celsius)—people slept an average of about 15 minutes less. 

"Many of us already do not get enough sleep, and the contribution of sleep issues relevant to global warming could have real consequences for our health and well-being," said Alex Agostini, a lecturer in the department of justice and society at the University of South Australia

The researchers also learned that, like other impacts of climate change, the effects of climate-induced sleep loss do not distribute evenly. Those living in lower-income countries, the elderly, and women will be most affected. 

Susan Clayton, who studies the implications of climate change for psychological well-being at the College of Wooster, says, 

"The implications are clear: higher temperatures associated with climate change are already reducing the amount of sleep people get and are projected to do so even more. Since we know that lack of sleep can negatively impact mood, behavior, health, and cognitive functioning, this is concerning."