It can be too hot to get to sleep; lost sleep contributes to poorer overall health and healing in humans

Screenshot of interactive map by Kasha Patel, The Washington Post, from CDC data

Google "It's too hot to sleep," and you'll find a myriad of articles teaming with a frustrating truth: If it's too warm, the human body does not want to doze. And with temperatures rising, sleeplessness is already a chronic problem in the U.S., reports Kasha Patel of The Washington Post. "A study estimates people are already losing an average of 44 hours of sleep per year."

The study by Nick Obradovich, a political science Ph.D. student at the University of California, points to a population that needs more rest and less heat. "Humans are already losing shut-eye in warm environments, especially at the beginning of the night. . . . . In his study looking at 47,000 adults in 68 countries, Obradovich and his colleagues found a notable change in sleep duration when nighttime temperatures rose above 50 degrees. On nights above 86 degrees, people slept about 14 minutes less on average. . . . Over longer chunks of time, the loss is stark: They estimate people are already losing an average of 44 hours of sleep per year. . . . Nights have warmed faster than daytime temperatures in many places around the globe. By 2100, individuals worldwide could lose about 50 to 58 hours of sleep per year."

Obradovich told Patel, “Right now, we’re not perfectly adapted to the climates in which we live. . . Hotter temperatures “harm our sleep kind of across the board, but that relationship increases in steepness. It becomes more significant in size the hotter the temperature gets.” Patel points out, "Not getting enough shut-eye can increase our risk for many serious health issues such as poor mental health, obesity, heart problems or even early death. . . . For instance, Rebecca Robbins, a scientist at Brigham and Women’s Hospital said our blood pressure dips to its lowest point in the day during our sleep. But without that natural dip, people are more likely to have elevated blood pressure, which can accelerate into hypertension, heart attack or stroke." Robins told her, "When we’re not meeting these sleep health targets, a lot of things start to go wrong. With more than just a night or two, this can become pretty problematic pretty quickly, putting stress on our vital organs, increasing risk for adverse outcomes and chronic conditions.”

People can try to regulate bedroom temperatures to help themselves fall asleep more quickly. Patel reports, "The ideal bedroom temperature for people to fall asleep is relatively cold — between 63 to 69 degrees. A drop in our core body temperature is essential for us falling and staying asleep because it simulates drowsiness. . . . Obradovich and his colleagues found unusually warm temperatures had the largest effect on people’s bedtime duration by delaying sleep onset. Short sleep durations were the worst during the summertime and among the elderly, probably because they have more difficulty regulating their body temperature. . . . . Lower income countries are also heavily affected, which Obradovich hypothesizes could be because of a lack of air-conditioning. But he plans to investigate further."