What does it take to sleep soundly? Surely we will think of the most obvious factors: silence, darkness, a certain inner peace, a firm and adaptable mattress, or the right pillow for our way of sleeping. Many times we forget about the temperature, until summer arrives and it becomes a problem.
Dreams, what they are for, and how they benefit you
Body temperature is one of the determining factors for inducing sleep, and follows a very well studied daily cycle. When the time to sleep approaches, our metabolism, that is, the amount of energy we consume just by being alive, slows down. This supposes a loss of heat and a small drop in our internal temperature of a degree or so.
It’s as if our body’s thermostat is set to a lower temperature during sleep, and our body does its best to maintain it. If it’s cold, we shiver in our sleep to generate heat. If it’s hot, we sweat to cool down. Here comes the concept of Thermal comfort and neutral temperature, which is what allows us to sleep without our body having to work to regulate its internal temperature. This corresponds to an ambient temperature of around 19ºC, and a temperature in the microclimate formed between the body, the bed and the sheets of around 30ºC.
The use of blankets and other types of coverage helps the body to maintain its ideal temperature when it is cold. On the contrary, previous studies have shown that regulation is much more difficult when it is too hot.
I can’t sleep in this heat
Excessive heat produces not only sweating. Unconsciously, the body seeks to expose more skin surface to the air to cool itself, and this causes us to sleep on our sides or toss and turn throughout the night. This causes REM sleep to decrease, during which dreams occur, and which is essential for emotional regulation. It also increases the number of times we wake up. If the temperature of the room rises above 28ºC, the body receives the signal that it is time to get up. That’s why it’s so hard to fall asleep in the heat.
Air conditioning is the most obvious solution for many people, but energy costs and energy poverty make this option difficult to access, not to mention the environmental impact. There are other alternatives that help lower body temperature and reduce the use of air conditioning. Since the most important factor is the immediate environment around the body, it makes sense to look at the mattress that we keep in contact with all night.
The so-called cold mattresses use materials of high thermal conductivity, that is, the heat of the body is transferred more quickly to the mattress, producing a sensation of freshness. This is achieved through breathable fibers and phase change materials that meld with body heat, absorbing even more heat in the process.
Some manufacturers have mattress covers to place on the bed that use ducts through which hot or cold air circulates, for winter or summer, which allows regulate the temperature at will. Some models have two zones with different temperatures for people who sleep together.
The cheapest alternative consists of cooling mattresses, mats of different sizes that are placed under the sheets and that have a network of tubes in their structure through which water circulates. The mat connects to an energy-efficient bedside evaporator that cools the water. According to the manufacturers, these devices allow to reduce body temperature between 3 and 7º, something that can mean the difference between sleeping well or not sleeping a wink.
What is all this based on?