When the days get shorter are we sadder? What science says

With the transition tosolar timewhich occurred between Saturday 25 and Sunday 26 October, the hands of the clocks have moved back an hourreducing the hours of evening light in our days, which will progressively shorten until winter solstice. This change may affect the our mood, making us feel more tired and down in the dumps, while at high latitudes the arrival of polar nightin which the sun does not fully rise for months, can cause real episodes of seasonal depression. If on the one hand, in fact, the cold and the early evening change change ours lifestyleson the other hand the reduced availability of light affects the production of key molecules for our well-being and mood, such as melatonin And serotonin. All these mechanisms together could explain the decline in our mood in wintera frequent phenomenon especially in Nordic countries and which according to some evolutionary theories could have represented a winning strategy for our ancestors who lived thousands of years ago.

Does sunlight affect our mood? The case of the Finnish Kaamosmasennus

Have you ever felt a little down in the dumps or more burdened at times of the year when it does dark early? If the answer is yes, you are not alone at all. For many of us, in fact, the progressive shortening of the days until the winter solstice is often accompanied by a drop in mood and gives a feeling of greater tiredness. And, as if that wasn’t enough, the passage from summer time to standard time at the end of October it “steals” an additional hour of evening light from us, making the days even shorter.

Yet, we Italianslike the inhabitants of the southernmost countries of Europe, we can consider ourselves lucky. In Finlandfor example, occurs between the end of November and January kaamosthe so-called “polar night“, during which the sun never goes above the horizon and the days oscillate between twilight and total darkness. Precisely in this period, many Finns experience a real form of seasonal depression characterized by a general decrease in mood and an increase in the feeling of tiredness. A condition so widespread that it has taken the name of kaamosmasennus (literally “winter depression”), which many studies link precisely with the poor exposure to sunlight.

Italians prefer days with more hours of evening light

In ItalyFortunately, we don’t have to deal with anything comparable to the Finnish kaamos. Yet, even here the days are yes they shorten drastically with the arrival of autumn and winter. To give a concrete example, in Naples in June the sun sets around 8.30pm, giving us more than 15 hours of light; at the end of December, however, the sky begins to darken around 4.30pm, giving us just over 9 hours of sunshine.

But Italians prefer them long summer days or those crepuscular typical of winter? According to a survey conducted in 2019 from the YouGov platform, on the occasion of the European Parliament’s proposal to abolish the time changeon a sample of 1007 interviewees 69% declared himself in favor ofpermanent adoption of summer timewith the aim of having available more hours of evening light in winter. A change, according to 62% of those interviewed, also motivated from the expectation of an improvement in mood resulting from the lengthening of the days.

Is there any scientific basis or is it just suggestion?

Definitely have it available more hours of light during the day allows us to spend more time outdoorscarry out physical activity and maintain a more active social lifeall activities known to “recharge” our mood and general well-being.

However, sunlight can have a much more direct influence on our bodies, influencing our neurobiology. In the retina, scattered among the cells that allow us to see shapes and colors, there are cells that act as actual “light sensors”. They are called intrinsically photosensitive retinal ganglion cells and they work in a similar way to those lamps that turn on automatically as soon as they detect a dark situation in the environment.

When dusk fallsin fact, these cells send a signal that warns the brain of the arrival of darknesswhich in response stimulates the production of melatoninthe hormone that promotes sleep. And since the days are shorter in winter, the Melatonin secretion starts earlier and lasts longerhelping to make us heard more sleepy. At the same time, light, through the cells themselves, influences the natural production cycle of serotoninthe famous “good mood molecule”. Not surprisingly, some studies have observed anomalous variations in the levels of these molecules in people who suffer from seasonal depressiona more common disorder during the cold months and with fewer hours of sunshine, and often treated effectively through light therapy.

If we are more tired in winter it is all the “fault” of evolution

Having reached this point, a question arises spontaneously: why does our biology seem to “hinder” us in cold seasonswhen the availability of ambient light is less? The answer, as often happens, must be sought in our past.

Our lifestyles have changed radically in the last two centuries, but our organism has evolved for millions of years adapting to environmental conditions very different from what we experience today. And before the invention of light bulbs, cities and heating systems, the arrival of winter and the shortening of the days they meant exposing oneself to predators and invisible nocturnal dangers, facing severe famine and freezing temperatures, all situations capable of seriously putting one’s life at risk.

But the biology might have found a solution”: make us slow down and feel more sad and apathetic during the coldest and darkest periods of the year. A strategy that might seem inappropriate today, but which for thousands of years may have defended us from the dangers of the harshest periods of the year, saving energy to face the challenges coming with the long, bright days of spring.