Under the effects of climate change, increasingly hot weather is affecting sleep quality. Scientists say humans must learn how to adapt, such as by taking cold showers and reducing alcohol or caffeine intake, adding, "If we always use air conditioning to sleep, we'll never be able to adapt."
The human brain is very sensitive to heat; higher temperatures can raise the body's central temperature and activate the stress system. Scientists are increasingly exploring mechanisms that help the body adapt to rising temperatures. Elevated temperatures can affect sleep, leading to health problems.
According to a scientific literature review published in the 2024 edition of the journal Sleep Medicine, climate change and urbanization have led to rising temperatures, threatening human sleep, thereby impacting health, performance, and well-being.
Research published in the 2022 journal One Earth indicates that during the first two decades of the 21st century, people averaged 44 hours less sleep each year compared to the past, which researchers attribute to rising temperatures.
A study by Maina, a researcher from the University of Copenhagen, based on data from over 47,000 people across 68 countries, shows that by 2099, intensified global warming could result in 50 to 58 hours less sleep per person annually.
Maina and the other authors of the report state: "To enhance adaptability and protect the fundamental restorative function of sleep in a hotter world, there is an urgent need for intervention studies and field experiments."
Neurons in the brain that regulate temperature and sleep are highly interconnected. Lowering body temperature is key to improving sleep quality.
Sauve, a researcher at Paris City University, says humans are "more tolerant of higher temperatures than generally believed." Several studies indicate a room temperature of 28 degrees Celsius can still allow for good sleep quality.
Sauve questions the "misconception that a bedroom must be maintained between 18 to 20 degrees Celsius," and suggests that wearing light clothing like t-shirts and shorts, using simple bedding, and ensuring good ventilation can handle slightly higher temperatures. But "if we always use air conditioning to sleep, we'll never adapt."
Additionally, scientists recommend taking a cold shower before bed, but not at a temperature that's too low; also, reducing the intake of stimulating drinks like coffee, and drinking less alcohol. Alcohol may aid sleep but slightly raises body temperature.
Research proves that napping during the hottest part of the day can also mitigate the effects of lack of sleep.
Sauve says that taking a short nap of 30 to 40 minutes before 2 PM can avoid interference with good sleep at night.