We’ve been on the brink of the earliest heatwave since 1981, and it means so many things: rising thermometers, heat strokes, problems performing daily activities… it becomes nearly impossible. That’s why we’ve put together this quick guide to sleeping more and better when the weather is very, very hot, according to science.

Close relationship between sleep and temperature. What we interpret as discomfort and inability to fall asleep has deeper roots in the close relationship between body (core) temperature and sleep. Although we often talk about circadian rhythms in relation to sleep and wakefulness, the truth is that they play a very important role in regulating body temperature, explains Philip Gehrman, professor of psychology at the University of Pennsylvania School of Medicine.

“Our core body temperature is lowest in the morning about two to three hours before our natural waking time and then rises throughout the day, peaking at night about two hours before we start to feel sleepy. Other researchers talk about 30 minutes before bed,” Gehrman explained. but the underlying logic is the same.

This is why when our temperature rises artificially (for example, after a hot shower), our body interprets it as a thermal peak and our sleepiness is triggered. Popular interpretation describes it as ‘relaxation’ but it is mainly due to thermal issue.

So why is it so hard to sleep in this heat?. The question is interesting: if heat induces sleep, it shouldn’t be difficult to sleep with it. But the problem arises when temperatures are consistently too high. In this state, the hormonal mechanisms that regulate circadian rhythms become uncoordinated and the chemical signals we receive are often contradictory. The result is clear: we have trouble sleeping.

Why is this happening? The reason is probably evolutionary. Malcolm von Schantz, a sleep neuroscientist at the University of Surrey, pointed out a few years ago that “as a species we are diurnal animals” and therefore “evolved to sleep at night, when it’s colder and darker.” As is always the case with evolutionary explanations, we do not have absolute certainties.

But the truth is, he’s sleeping. In a well-known experiment, Kazue Okamoto-Mizuno and Koh Mizuno showed that changes in temperature serve as a “biological clock” and play an important role in regulating sleep. To give us an idea of ​​how serious this relationship is, people with insomnia “show that their basal temperature is higher just before going to sleep than people without sleep problems.”

What can we do to improve sleep? In short: it’s harder to fall asleep in a high-temperature environment, and when that’s reached it’s very poor quality (fragmented and not very restful). Diagnosis is clear, missing solutions. In this context, there are three broad things we can do to improve sleep quality: physical, physiological and behavioral measures.

A cool and secluded environment By “physical measures” we mean, first of all, choosing the most isolated room in the house and, if possible, the lower room, as the heat tends to rise to the upper floors. In addition, we must do everything possible to prevent the room from heating up during the day: during hot hours, windows, doors and shutters should be closed and insulated.

However, it is recommended to catch fresh and renewed air inside the house at night and in the first hours of the day. To do this, you have to let the night air into the rooms (yes, it controls the entry of mosquitoes) and ventilate first thing in the morning, keep the windows open long enough and no more.

Using physiology to our advantage. Physiological measures are little tricks that help us “reorganize” our body and function better in the midst of thermal dysregulation. Showers can be beneficial for improving thermal sensation without going any further, but they can also make us sweat less (and sweat is our main biological cooling system). On the other hand, it is not recommended to exercise too close to bedtime, as an increase in body temperature can add more confusion to our hormonal cycles.

One more thing. But, as always, the key to sleeping more and better is in our behavior and traditions. Wearing the right clothes (too much clothing can make it harder to sweat), not drinking alcohol (which can affect the body’s ability to regulate temperature), not eating too much (which increases the amount of blood in the body and therefore, raises the body temperature), or drinking enough water (water is a big deal depending on how we use it). can be an ally) are simple measures that make the body work more efficiently.

Image | Braden Barvic