It is no accident that hell is a hot place. The cold hurts, it’s sharp, it can kill you; but the heat, the real heat, is a kind of torture many times worse than any other we could have imagined.
At least, I am not able to imagine many more desperate punishments than being condemned to sleep every night to many more degrees than reasonable. The same is because it is 3:27 in the morning, 20 minutes ago I woke up drenched in sweat and since then I have been looking for what science says about how to sleep in summer when we don’t have air conditioning.
Can you sleep cool without air conditioning or a fan?
v And I admit that I am deeply disappointed. This is one of those issues that shows us that science does not address the real social priorities: there are many researchers trying to send humans to Mars, cure diseases or stop climate change. But what about sleeping in the summer? Is nobody going to investigate how to sleep in summer?
Perhaps I am exaggerating a bit, but the truth is that there is little research on this topic. Nevertheless, we can use what we know about “evidence-based sleep”to draw some conclusions, using books such as ‘Clinical guide on sleep disorders in children and adolescents’.
And the first conclusion is that, although researchers have not agreed on the ideal temperature for sleeping (some suggest that it is about 18.3ºC, but there is no consensus), they have agreed on a fundamental idea: sleeping in the heat is objectively a bad idea.
Why do we sleep badly when it’s hot?
There are researchers like Malcolm von Schantz, a sleep neuroscientist at the University of Surrey, who believes the reason is evolutionary: “As a species, we are diurnal animals.” Namely, “we have evolved to sleep at nightwhen it’s colder and darker”. Therefore, temperature changes tell us that something is not working well: they serve as a ‘natural clock’ and we wake up, as Kazue Okamoto-Mizuno and Koh Mizuno also pointed out in their study.
Whatever the reason, it is true that during sleep our temperature changes between wakefulness and sleep. In fact, “thermal regulation is a significant factor” in sleep regulationexplained Professor Cameron Van Den Heuvel of the University of Adelaide. “About an hour to 30 minutes before bedtime, the body begins to lose body heat. This increases feelings of tiredness in normal healthy adults.”
People with insomnia, without going any further, “show that they have a higher basal temperature just before sleeping than people who do not have sleep problems.” The ambient heat does not help this thermal reduction and it seems more than proven that when the temperature is very high, it is more difficult to fall asleep and, when it is achieved, this is of very poor quality (fragmented and with few dreams).
Alternatives to air conditioning: how to cool the house naturally
By trawling through the scientific literature, advice for sleeping can be organized around two main themes: advice for replacing the air conditioner (that is, for cool or prevent the space where we sleep from heating up) and tips for using our own physiology to help us fall asleep.
The first move is to do everything possible to prevent the room from heating up during the day and introduce it into our usual practice. Experts recommend choosing the most isolated room in the place and, if possible, the lowest as well (the heat tends to rise to the upper floors).
Once selected, it must be isolated by closing windows, doors and shutters during the day. When night falls, the outside temperature usually drops: it is time to open them and create a small current that will cool the entire house. A fan can also help us, especially if it is programmable and we can activate an automatic shutdown when we calculate that we will be asleep.
In addition to that, choose light bedding (the natural fibers absorb sweat better than synthetic ones) and summer pajamas (or no pajamas at all). With the heat, sleep becomes fragmentary and it is better that we are as cool as possible. And in addition to natural fibers and the lowering of blinds.
How to sleep well when it’s very hot: take advantage of our physiology in a smart way
As we said, water can be a great ally depending on how we use it. This is where using our physiology wisely comes in: a shower can help improve wind chill, but it can also make us feel colder and sweat less. This is a problem because, remember, sweat, like the tongue in dogs, is our main biological cooling system.
Cold or hot? In this case, it is a matter of preference: the two options seem reasonable, and although in principle the cold shower seems more interesting, there are experts who are inclined to recommend a hot shower on a warm night. The hot shower increases the humidity of the environment and the more humidity there is in the environment, the more difficult it will be for our sweat to evaporate – and that evaporation reduces our temperature. Therefore, it is not a bad idea to use dehumidifiers.
It is also recommended not exercising too close to bedtime, due to the increase in body temperature that it produces. Thus, exercise during the day or earlier than sleep is indeed helpful because it contributes to tiredness since it does not fall asleep, but in time so that we can relax after that shower (whether it is hot or not).
The last idea related to water is sleep – slightly – wet. This is a “remedy” that dates back to the time of the Egyptians who used moistened mats or rugs to fall asleep on the banks of the Nile. It’s not crazy, although I recognize that it takes a bit of practice. It is not easy to sleep comfortably if you are wet.
A hygienic dream: eating, sleeping and sunbathing
The rest of the ideas that we can find are tips for sleep hygiene in general: Stay hydrated (sweating causes us to lose a lot of water and electrolytes), not having copious dinners (sleep is bad enough without having to digest) and take care of your skin (burns don’t help you sleep). It is also advisable to avoid alcohol before sleeping. Alcohol is a natural dehydrating agent and therefore contributes to the problem
You already know that in this house we are very fond of siestas and for good reason. But the fact is that a nap is also a good idea: not because it helps us to sleep cooler, but because helps us get back to sleep. If later at night it becomes difficult to sleep, that’s what we have spare.
Prepare for the heat
Beyond four simple tips and a couple of tricks to trick our body, what seems clear in the scientific literature is that there are no big secrets or magic recipes: when it’s hot, we sleep badly.
And, from what the experts point out, it’s going to be very hot in the future, with the impact that that will have on the quality of sleep for all of us. It’s not a bad time, then, for thoroughly investigate other alternatives: Let’s hope someone does.
A previous version of this theme was published in 2017.
Image | Joyce Romero
George is Digismak’s reported cum editor with 13 years of experience in Journalism