The degree of exposure to natural sunlight and hours of night-time rest are decisive factors in many aspects of human health.
Most living beings structure their lives according to biological patterns or rhythms that repeat themselves every solar cycle, approximately every 24 hours. These patterns are known as circadian rhythms, which are responsible for regulating body temperature, metabolic and hormonal activity, as well as sleep and wakefulness.
Since ancient times, these rhythms have constituted the internal clock that regulates natural physiological processes, which are calibrated by external stimuli such as eating routines, hours of exposure to sunlight, and night-time sleep.
This occurs because the brain receives different stimuli during the day and night.
The human circadian rhythm is controlled by the hypothalamus, a region of the brain that receives signals about light and darkness through the retina of the eyes. These signals are transmitted to the pituitary gland, which is responsible for the production of melatonin, whose function is to prepare the body for sleep.
Similarly, when the retina detects sunlight, melatonin production is inhibited and the brain sends information to the adrenal glands, which are responsible for producing cortisol, promoting alertness and wakefulness during the day.
The time of day with the highest concentration of light is midday. This moment is interpreted by the brain as the moment of maximum daytime activation, which gradually decreases until sunset.
But what happens when we live far from natural environments and lifestyles that make us want to maintain an active nightlife, thanks to the existence of artificial light?
When night falls, our brain receives erroneous information, interpreting it as a moment that is not.
Overexposure to artificial light after sunset keeps cortisol production active in the adrenal glands and inhibits the production of melatonin, which is responsible for restorative rest, cell regeneration and the proper functioning of our body’s metabolism. As a result, we may suffer from sleep disorders, metabolic disturbances, mood swings and all the processes that the body must perform to maintain proper health.
To avoid these disturbances in our circadian rhythms, we can take the following into account:
- Establish routines and schedules that allow us to adapt more gradually to the transitions between day and night.
- Avoid the use of electric light during the day as much as possible, always prioritising natural sunlight.
- After sunset, if artificial light is necessary, it is advisable to always use warm-toned lights, such as orange, red, and infrared, which are most similar to the light of a fire or the light emitted by the sun throughout the day, along with the blue light of midday.
- Avoid the use of screens, mobile phones and other artificial light devices, such as fluorescent lights, white light bulbs or excessive lighting in all rooms of the house as much as possible.
Improving the quality of our sleep and, consequently, our health is possible if we take these considerations into account, in addition to establishing schedules and routines that promote proper digestion and assimilation of the nutrients essential for the body’s metabolic and hormonal function.
Balancing light and darkness as a manifestation of overall health is a challenge for many modern human beings.
That is why, in our rural house, in addition to having an excellent south-facing orientation that allows us to enjoy natural light throughout the day, we have warm artificial lighting in all spaces, both indoors and outdoors.
Warm light invites rest and connection with our wildest nature. It allows our body and mind to feel safe, where we can rest and find the peace we so desperately need.