Hotter Nights Decrease Sleep Quantity and Quality

Hotter Nights Decrease Sleep Quantity and Quality

Climate change already impacts daily life, from intense wildfires to reservoir-emptying droughts. Now, a new study shows the connection between rising global temperatures from climate change and worsening sleep. Researchers tracked the sleep of people all over the world for two years. They found that poor sleep generally began at temperatures above 77°F (25°C) and got worse when they crawled above 86°F (30°C). Those living in lower-income countries were shown to experience more extreme impacts than their wealthier counterparts, which researchers speculate is due to the difference in air conditioning access. They also found that warming could result in up to 15 days of bad sleep a year by the end of the century.

SciShow: Can’t Sleep? Blame the Climate Crisis, May 20, 2022.

Why This Matters

Sleep is essential to both day-to-day living and long-term health. Over time, sleep deprivation can increase the risk of heart disease, intensify mood disorders, slow learning ability, and much more -- all of which are problems with high personal, societal, and economic costs. Even 15 minutes less of sleep a night can cause a significant impact since those minutes likely come from one of the most restorative sleep phases. In the US, nighttime warming is happening at a faster rate than during the day.

“This moves the effects of climate change out of the catastrophic and existential and shows how it affects us every day,” Jamie Mullins, an environmental economist at the University of Massachusetts at Amherst who was not involved in the research, told National Geographic. “It’s going to cost us all in small ways that really add up.

Reuters: World could see 1.5C of warming in next five years, May 10, 2022.

No Adaptation

The study also found that the human body doesn’t adapt to warmer overnight temperatures. Just a few degrees can be the difference between quality and poor sleep, and living through a series of hot summer nights doesn’t budge those thresholds.

The study underlines that more people will need air conditioning as the planet warms. Because additional units will come onto the grid, the increased demand for power should be yet another incentive to clean up the nation’s and world’s energy systems.

The Lancet: Global launch event | 2021 Lancet Countdown on health and climate change, October 27, 2021.

TED: End fossil fuels to protect human health | Carolyn Orr, March 1, 2022.