The Power of Light and our Internal Clock

The Power of Light and our Internal Clock

Last update: 13 February, 2018

Light has always been associated with positive emotions. In the summer, when the days are longer and there is more light, it seems that our joy abounds. There are no better unforgettable moments than those spent on wonderful sunny days by the sea, on a picnic in the mountains or enjoying the sun on a small terrace. The power of light shouldn’t be underestimated.

Spring and summer, with their light, are periods of expansion, of venturing and experimenting. They are a counterpoint to autumn and winter, with their rain and shorter days, and which encourage us to return to the shelter of our homes.

Our body, which is part of nature, perceives changes in the environment and, through physiological mechanisms such as the secretion of hormones, makes us feel either more or less energetic, depending on the cycle or season we find ourselves in.

In the same way that our moods and energy fluctuate with the seasons, they also do so with shorter cycles, such as night and day.

The power of light and natural cycles

The hypothalamus is a small region that is located in the deepest part of the brain, the so-called reptilian brain. It is an essential structure that is responsible for regulating the basic processes of life, such as body temperature, food and fluid intake or libido, as well as regulating emotions. We feel hungry or full, anxiety or calm…depending on the hormones that this part of the brain secretes.

Human brain

As with everything that has to do with the brain, it is a very complex structure. However, one thing we do know with certainty is that one of the factors that decisively influences the function of the hypothalamus is the light it receives from the outside world.

The brain has evolved from the hand of nature, and the most “natural” thing is that during the day, when the brain receives plenty of sunlight, it understands that it is time to be active. Conversely, at night, when we are surrounded by darkness, it is time for rest and renewal. These days, however, these periods are no longer fixed. With artificial light, we can be awake until the wee hours of the morning.

This alteration of the natural cycles upsets our internal clock and affects our health.

Not respecting natural cycles affects health

Our body and our internal clock are designed to respect the cycles of light. During the day, we need to be exposed sunlight to maintain optimal energy levels. Artificial light is not a substitute for sunlight. That is why in many cases fatigue overpowers us, and we feel that we need a coffee to be able to get everything done.

Where the air and the sun come in, the doctor does not enter. (Popular saying)

In the long run, a deficit of direct sunlight increases the risk of suffering from depression. That is why in winter, when the days are shorter and we leave work when it’s already getting dark, it is much more common for people to suffer from depression. In addition to this, the sun is the most important source of vitamin D, which is essential for calcium in the bones. The power of light can touch our bodies in so many ways.

The power of light can beat tiredness

How we wake up is important

Another of the most amazing examples of the power of light over our organism has to do with the way we wake up. We usually set the alarm clock for a specific time in the morning, and that alarm interrupts our sleep very abruptly. We turn on the light in the room, going from the darkness of the night to the light of day in a matter of seconds.

In nature, dawn is something that happens progressively, and our brain is programmed to wake up in that way. With the gradual increase in natural light, the brain wakes up and gradually leaves the world of dreams. Not respecting our bodies in this way is the reason that we can’t get out from under the covers. It’s so difficult to get started in the morning!

Apart from the obvious sleepiness we have when we get up, this way of waking up causes us to carry this fatigue with us throughout the day. It causes us great stress, because the natural sleep processes, so necessary for a good rest and renewal haven’t worked correctly.

Regulate the internal clock

There are some things we can do to regulate our internal clock:

  • Try to adjust your schedules as much as possible to the natural cycles by listening to your body. Some people are more active during the morning and others in the afternoons, but staying up until the early hours of the morning is not usually a good thing for anyone.
Alarm clock
  • During the day, try to spend as much time as possible in the natural light of the sun. This is very complicated in our busy modern lives, but try to get direct sunlight for at least half an hour a day. Again, the power of light is essential.
  • Try to make the environment around you as dark as possible in the hours before you go to sleep. Turn on as few lights as possible and if you can avoid computer or mobile screens, then please do.
  • Try not to wake up abruptly. As it is almost impossible to wake up with the natural light of dawn, since this does not fit into our schedules, a good solution to this is a “gradual dawn” clock. This is an alarm clock that progressively illuminates the room until the time we have to wake up, imitating what would be a real sunrise.

If you feel stressed or down and do not know why, if you feel that you lack energy or are tired from the moment you wake up, review your time routines and try to fit with the cycles of the day and night of nature as much as possible. You’ll soon notice a difference.


This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.