With the arrival of colder, rainy and darker days, social networks are filled with images of cozy and warm interiors: a couch, a blanket, a brewing tea, a movie or a book. Why go out if you don’t have to? This stay at home helps to understand the figure that is always repeated when we talk about the spaces in which we spend our days: between 85% and 90% of our time is spent indoors. The European Commission said this in 2003 about the EU population, and also published a study in nature 2001, according to which Americans spend 87% of their time in closed buildings and 6% in closed vehicles.
The number of hours we spend between the four walls changes depending on the season: in the summer we are outside more if we can and it is not sweltering, and in the winter we are more inclined to take shelter in closed spaces, although, according to a survey carried out in 2021 by the company OnePoll, it all depends on that too which is our favorite station. However, unless we’re working outdoors, chances are we’ll spend an average of 85-90% of that time indoors. What are we missing if we can’t spend more time outside?
“Light is the synchronizer of the circadian system,” explains María José Martínez Madrid, MD from the University of Murcia and coordinator of the chronobiology working group of the Spanish Sleep Society (SES). Recommendations for good sleep hygiene usually focus on not getting too much light at night, but exposure to it during the day is just as important. “You have to get natural light during the day, at least two hours, although it’s harder than it seems. But if light is not received during the day, then no melatonin is synthesized at night. It is a mechanism that needs that contrast, daylight and darkness at night. If we don’t get light during the day, we will be sleepier and less active, and we will sleep worse at night,” he points out.
Although artificial light keeps us awake at night, the light we get during the day must be natural, if possible received directly and not through a window. “When we get light from the computer, even all day, it is scarce. Although it is blue light, it is a light that does not have the intensity we need nor does it have the full spectrum of light,” he explains.
Time spent outdoors is also associated with better visual health, which is also supported by a lot of scientific opinion. One of the latest studies, from this year, concluded that, although the intensity of indoor light did not affect the development of myopia in children (the classic “if you read in the dark, you will damage your vision” myth is enough), time spent outdoors did: increasing this time protects children without myopia from myopia. This study did not find the same result for children who were already myopic (that it slowed the increase in their myopia), but others did.
Ophthalmologist Rosario Gómez de Liaño, head of the strabismus department at the San Carlos Clinical Hospital, president of the International Strabological Society and full professor at the Complutense University of Madrid, explains that these benefits of living abroad come in different ways. “It is known, for example, that they are ultraviolet, which can affect various mechanisms”, he points out.
Eye care recommendations for computer work always recommend taking breaks to look into the distance, so it’s tempting to attribute the benefits of being outdoors to the fact that we’re more likely to have eyes that look beyond a few inches. However, Gómez de Liaño insists that light is the most important thing. “It was seen, for example, that if a child reads at home or outside the home, it is completely different. It wasn’t the fact of playing and watching from afar, it was the fact of light,” he emphasizes.
The importance of mental health
A few months ago, a video appeared with a girl excessively grumpily walking along a path full of snow, in rhythm musiquilla animated with the text “taking a stupid walk through my stupid mental health”. Going for a walk, breathing fresh air, is one of the tips that is often repeated like the hand of a saint when we have a bad day.
“When we go out into the street, we realize that there is another world. And because of this, we see that inside the house we don’t feel as good as we could feel if we went out more”, explains Juan Ignacio Aragonés, professor of social psychology at the Complutense University of Madrid and member of the Psicamb Environmental Psychology Association. . Additionally, there are more opportunities for social interaction, which can also increase that well-being. However, he clarifies that he is not saying this with data in hand, but from “common sense”.
The data proves him right. According to a study published last year by the EUl Journal of affective disorders, the average time more than 400,000 British participants spent abroad each day was 2.5 hours. Each additional hour was associated with lower odds of depression and antidepressant use, lower frequency of anhedonia and low mood, lower neuroticism, and higher self-perceived happiness.
Although all this may mean that you go out more because you feel better, and not the other way around, reasons are being sought to prove that this stupid walk can help our stupid mental health. Various investigations have focused on three. First of all, exposure to natural light, which, among other things, regulates melatonin, serotonin and cortisol cycles. Changes in these circadian cycles are linked to depression, so helping to regulate one could help keep the other at bay.
There is also a relationship between the time we spend outside and physical activity: outside the home we tend to be more active (even if it’s a walk), which also helps us feel better. Finally, the positive effect of spending time in natural spaces is well-studied: according to a 2019 study, two hours a week in natural spaces is associated with better health and better overall well-being. If our going out goes through a park or a trip to the forest, the benefits are greater.
But what if you spend that time outdoors in an urban, polluted and ultimately stressful environment? That’s the criticism leveled by a study published in 2016 in the journal American Journal of Preventive Medicine: “Study results support the idea that increasing time spent outdoors can result in mental health benefits. However, this study questions whether this benefit is equal across different groups, particularly given differences in occupational experiences and neighborhood environmental characteristics.
In the same vein, Dr. Rosario Gómez de Liaño refers to recent research that links pollution to an increase in myopia. These, he insists, are aspects that are still being studied and “not all studies or all journals are the same”, so some of these things “will remain and others will not”, but this is something that must also be taken into account.
In other words, going out into the street in a semi-pedestrian district, with parks and green areas, is not the same as in one occupied by traffic and asphalt. If the environment is friendly, the health benefits are multiplied.
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