The Science of The Sun: How Light Affects Our Mental Health

We, as humans, revolve our lives around the cycle of the sun. We have done this pretty much since the creation/development of our species. To this day, humans consider the time when the sun goes down to be night time, and time to power down.

It is a time for our body to sleep and rejuvenate for the next day.


This stems all the way back to our first ancestors and cavemen who would return to their camps at night for protection from the elements and animals.

When the sun starts peeking through our windows at 5-6 in the morning, we know that the day is fast approaching and soon we will have to roll out of bed and attack the day.

When there is an overcast week, most people get the bad weather blues. But it’s actually not the weather’s fault at all- it is the lack of sunshine that encourages your mopey and drained feelings.

This feeling can also overcome individuals in the winter months and is scientifically termed “Seasonal Affective Disorder.” 

Why is light important?

Light is necessary for the survival of life on Earth because almost all energy used by life is derived from the sun. Plants and algae use light energy in photosynthesis, which provides usable chemical energy for heterotrophic organisms. Plus, without light, the Earth would be completely cold and dark since even the moon gets its glow from reflecting the sun.

Association Between Darkness and Depression:shutterstock_370182893

The association between darkness and depression is well established. A study published in the Proceedings of the National Academy of Sciences discovered (for the first time) the profound changes that light deficiencies cause in the brain.

Neuroscientists at the University of Pennsylvania subjected rats to utter darkness for a period of six weeks.

During this time, the animals not only exhibited depressive behavior, but also suffered damage in specific brain regions. The brain regions which were targeted are known to be under active in humans during depression.

The Effects:

The researchers observed neurons that produce norepinephrine, dopamine and serotonin—common neurotransmitters involved in emotion, pleasure and cognition—in the process of dying. This neuronal death, is often accompanied by shutterstock_15088066compromised synaptic connections, which may be the underlying factor of the darkness-related blues of seasonal affective disorder.

Researchers speculate that the dark-induced effects stem from a disruption of the body’s clock.

Researchers believe that when the circadian system is not receiving normal light, it in turn might lead to changes in brain systems that regulate mood.


Treating the rats with an antidepressant significantly improved brain damage and depressive behaviors. This study is particularly relevant to seasonal affective disorder, but scientists say that it could be related to depression overall.

Basically, if you find yourself feeling blue, flip on a light or go outside and bask in the warmth of the sun. Your mentality will improve and you can say “bye-bye” to your depressive symptoms.

Written by: The Hearty Soul


Leave a Reply

Your email address will not be published.