Most people think of light as something that only allows for visibility of their direct environment. (Sun)light, for instance, allows you to see what’s going on around you. And at nighttime, the absence of light makes your environment invisible.
Sounds simple, right?
For health, however, there’s more to the story:
In fact, the light in your environment directly affects your health. Sufficient levels of light exposure, in fact, is essential for the human body!
Why?
That statement sounds really abstract so allow me to explain:
For millions of years, sunlight was the main light source in the human environment. Those brightness-providing sun rays actually penetrate the skin's surface. In other words, light can thus directly venture into your body to affect chemical processes therein (1; 2):
Today, many people spend most of their time indoors - artificial light bulbs have become the main source of light exposure for humans.
To understand why that difference matters, let’s dig a bit deeper into what “light” is:
From a physics perspective, light is made up of “wavelengths”. Some of those wavelengths of light - such as infrared - warm the body from within. As a result, you’ll get feelings of a greater sense of well-being, have more energy, and perform better.
When you’re outside, the wavelengths emitted by the sun provide you with that feeling.
If you’re indoors all the time, you won’t get sufficient light exposure, and unfortunately, won’t reap those benefits.