A new analysis has found that rising nighttime temperatures are increasingly affecting people’s ability to get a good night’s sleep. Climate change is contributing to the loss of several hours of rest each year.
Researchers from Climate Central estimate that the average person now loses approximately 56 hours of sleep annually due to uncomfortably warm nights. Of that total, about five hours per year are directly linked to human-driven climate change. This highlights one of the lesser-known health impacts of rising global temperatures.
Hotter Nights Are Making Quality Sleep More Difficult
The study analyzed temperature data from more than 1,300 cities worldwide. Researchers compared today’s climate with a modeled scenario in which human-caused climate change had not occurred.
Scientists found that nighttime temperatures have risen steadily over recent decades, making it increasingly difficult for people to fall asleep and remain asleep throughout the night. In addition, researchers note that the additional sleep loss attributed to climate change has roughly doubled since the 1970s. This loss is expected to continue increasing as global temperatures rise.
Unlike daytime heat, warmer nights provide little opportunity for the body to recover. This reduces the natural cooling process that helps initiate healthy sleep.
Sleep Quality Declines as Temperatures Rise
Previous sleep research has consistently shown that excessive heat negatively affects both the duration and quality of sleep. Higher nighttime temperatures can delay the onset of sleep and increase nighttime awakenings. Furthermore, they can reduce restorative stages of sleep, particularly rapid eye movement (REM) sleep. REM sleep plays an important role in memory, learning, and emotional regulation.
Researchers also point out that the health impacts of chronic sleep loss may become more significant over time. This is especially true for individuals already vulnerable to cardiovascular disease, metabolic disorders, or mental health conditions.
People without access to air conditioning or other cooling systems may face an even greater risk of sleep disruption during prolonged heat waves.
Rising Temperatures Present a Growing Public Health Challenge
Experts say the findings demonstrate another way climate change is affecting daily life beyond extreme weather events. As overnight temperatures continue to increase, scientists expect sleep-related health impacts to become more widespread. In particular, this is true in urban areas where heat tends to remain trapped after sunset.
Health professionals recommend keeping bedrooms as cool as possible, improving ventilation, staying hydrated, and using cooling strategies during periods of extreme heat to improve sleep quality.
The researchers conclude that reducing greenhouse gas emissions remains essential for limiting future warming and protecting public health. This includes one of the body’s most fundamental needs: restorative sleep.
