María López slept perfectly but, a year ago, she began to suffer chronic insomnia, a silent epidemic that has multiplied in recent years. If in the year 2000 6% of Spaniards suffered from this disorder, in 2018 14% suffered from it and in the pandemic it temporarily shot up to 57%. The problem is that the torrid nights caused by the current heat wave They especially affect insomniacs. “A month ago I had started to improve but I have relapsed. Last night I woke up at two and I didn’t sleep a wink again,” explains María. When I stay up all night I get psychosis that the heat is going to prevent me from sleeping well again and I’m afraid of going back to the starting square, I’m desperate”.
And it is not the only one. Temperatures above 25ºC at bedtime affect anyone regardless of age and previous problems. Barcelona has already had two torrid nights and a large number of residents, from adults to children, have difficulties resting. “Tonight I felt how my eyelids were sweating,” says Montse, 50. “I haven’t slept a wink, I have gotten up more than five timesI have even read a book that I found in the living room. I didn’t stop sweating and in the end I was able to rest a little one meter from the fan,” says Xavier, a 17-year-old from Barcelona.
Why doesn’t the heat stop sleeping?
But what exactly does it cause in our brain And in our body the heat that prevents us from sleeping well? High temperatures, from 22 or 23ºC and depending on whether there is more or less humidity, cause various processes. On one hand, the neurons which are in the hypothalamus and control sleep and wakefulness “are guided by light and body temperature and, if this is higher, it costs more to sleep& rdquor ;, he explains Diego Redolar-Ripollneuropsychologist and professor at the Open University of Catalonia (UOC).
The nervious system
Likewise, “with high temperatures certain parts of the nervous system to try to avoid overheating of the body and that indicates to our brain that we are awake & rdquor ;, he adds and gives as an example the sweat as a mechanism to lower the temperature.
Finally, a third factor would be that heat “can be a stressful agent and therefore release substances that prevent sleep, such as cortisoland activate the sympathetic nervous system & rdquor ;.
“The temperature is fundamental and we need it to drop so that the hormones that allow us to sleep are secreted”
Ainhoa Álvarez, expert from the Spanish Sleep Society
“Temperature is essential in the 24-hour circadian rhythm and we need the temperature to drop so that the hormones that allow us to sleep are secreted, such as melatonin& rdquor ;, summarizes in turn Ainhoa Alvarezcoordinator of the insomnia working group of the Spanish Sleep Society.
All these processes are triggered in most people during tropical nights, but the most vulnerable are those who already suffer from chronic insomnia, especially if it is linked to anxiety. “Anxiety activates the sympathetic nervous system and the heat adds fuel to the fire,” Redolar exemplifies.
consultations and drugs
For all this, the queries to specialists or drug intake to sleep increase during heat waves. High temperatures do not cause chronic insomnia, that is, prolonged over time, but this usually disappears when the values drop, but it does cause insomniac people relapse. “We see many relapses in the consultations,” confirms Dr. Álvarez.
Less than a third of people with sleep problems consult with specialists
And an added problem is that less than a third of people with problems to sleepthey seek help professional, according to calculations by the Spanish Society of Neurology. The rest he medicates on his own with milder drugs and of doubtful efficiency, such as syrups or pills with melatonin, and other stronger ones that create dependency, such as tranquilizers and sleeping pills. In fact, Spain is the leader in consumption of anxiolytics and hypnotics. In the last decade the sale of medicines to fall asleep has increased by 21%.
The consequences
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The problem is that sleep is a physiological process of vital importance for the integral health of the human being. Scientific evidence indicates that not resting well for a long time has cognitive effects, in short-term memory and in the speed of information processing, while causing headaches, more fatigue and lack of energy. It also causes a greater appetite for fats and carbohydrates and, therefore, diet worsens Some studies also indicate that it affects the immune system and, in the long term, becomes a risk factor when it comes to developing degenerative diseases.
Despite this, insomnia is a growing disorder in Spain and in most Western countries, due to the current lifestyle, hyperproductive and hyperconnected. More and more is being sought, but since there is no time to reconcile everything, specialists point out, worries are often taken to bed and hinder good quality sleep.