Benefits of Sun and Daylight: Beyond Vitamin D

We saw the importance of limiting artificial light at night, and how it will improve your overall health if you let darkness rule. Today we are talking about the counterpart, which would be to be exposed to natural light during the day.

Our species evolved outdoors, and we still need natural light to synchronize our ancestral biological clock. In this article, you will understand the benefits of natural light and of exposing your skin to the sun in moderation.

THE SUN AS MEDICINE

At the beginning of the 20th century, the tools of medicine were scarce, and they had to take advantage of those offered by nature, the sun being one of them.

Many hospitals and sanatoriums took their beds outside because they knew that the sun offered to heal. In a world without antibiotics, the sun was one of the few known strategies against diseases such as tuberculosis. Today we know that sunlight strengthens our innate immunity, helping to combat the bacteria that cause tuberculosis (study, study).

With the advance of conventional medicine, we forget about natural light, but it is still fundamental. Patients in rooms with windows suffer less mortality and recover before their illness (study, study, study). After surgery, patients in sunny rooms report less pain and require less pain medication (study).

But as we saw in the previous article, our relationship with the natural cycles of light and darkness changed radically in a short time. We are exposed to less light during the day and less darkness during the night, which can cause us to lose our biological clock.

We are exposed to a lot of artificial light at night and little natural light during the day.

BENEFITS OF NATURAL LIGHT

Many benefits of natural light are obtained through the eyes, but we also need to expose the skin. Ultraviolet radiation regulates the production of multiple molecules and hormones on contact with the skin, which could be considered as one more endocrine organ (revision, revision).

1. BETTER CIRCADIAN RHYTHM AND REST

Throughout our history, the beginning of the day was marked by the sun, not the alarm clock. The morning light synchronizes our circadian rhythm, optimizing the functioning of our entire physiology (detail).

To perform this synchronization we need early exposure to intensities above 1,000 lux of brightness (detail). Even on a cloudy day, this value is easily achieved through natural light, but most offices have lower levels (detail).

At present, we spend less than an hour a day exposed to lights above 1,000 lux (studio), especially in winter (studio).

Early exposure to natural light adjusts our circadian rhythm. Source: Wild Health

In addition, exposure to bright lights during the day mitigates the negative impact of artificial light at night (study, study, study), improving nighttime sleep (study).

2. IMPROVED COGNITIVE PERFORMANCE AND PRODUCTIVITY

Natural light was the ancestral sign that marked our period of activity. It, therefore, activates our brain and keeps us alert (study).

Animal studies show how light improves the brain: rats exposed to 1,000 lux during the day produce more BDNF (involved in brain plasticity and neurogenesis) and present larger seahorses (study), improving their performance in different cognitive tests. Ultraviolet rays enhance the effect when they contact the skin by regulating the synthesis of the neurotransmitter glutamate (study).

Passing to humans, children with windows in their classrooms perform better than those in poorly lit classrooms (study, detail).

Workers whose jobs are closer to windows report improved well-being and better nighttime sleep, sleeping 46 more minutes (study). Not only that, they also get more physical activity: light promotes movement (study).

Daylight during the day makes us sleep better at night and increases our desire to move. Source:

Although it is ideal to use sunlight, artificial light rich in the blue spectrum also improves work performance (study). In hospitals, brighter lights reduce medical errors (detail).

In controlled trials, one hour of exposure to blue light produces improvements equivalent to a good dose of caffeine (study).

3. LESS DEPRESSION

Throughout our history, short, dark days were associated with harsh winters, and evolutionarily it made sense to develop a slight depression, which saved energy by inducing a kind of hibernation (detail, detail).

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