Does Light Affect Mood?
Exposure to light in moderation, especially natural sunlight, can have an uplifting effect on mood, while excessive darkness can have the opposite effect. This is mainly due to the way light affects serotonin levels, sleep cycles, vitamin D levels, endorphin production, and other chemical processes, and how these all relate to happiness, depression, and other moods.
Some of the effects of light are direct chemical reactions, such as the skin’s ability synthesize Vitamin D from sunlight. Some effects are just the brain picking up on light and darkness via the senses. For instance, when it comes to sleep cycles it doesn’t matter much if it’s light from your tablet, phone, or computer or the sun.
This Khan Academy video gives you an introduction to light. Understanding what light is can help understand how it affects our mood.
TIP: Speaking of light from computers and phones, it is a myth that reading in dim light can damage your eyesight.
Different Types of Light Affect Moods Differently
It’s important to note that the sun produces three types of Ultraviolet Radiation (UVR) (1. UVA, 2. UVB, and 3. UVC) that all have different effects. Beyond that, the exact ratio of the colors in the spectrum of sunlight is different than most light produced artificially. Each light type (including each color and the three UV types) has its own wavelength, health risks, and health benefits. Below we discuss the different ways light can affect mood in detail.
A video talking about Serotonin, Dopamine, and your brain. Sunlight affects all three.
FACT: The form of depression most often associated with variations in sunlight is Seasonal Affective Disorder (SAD). Given what studies have shown about the effects of light on happiness, it makes sense that variations in light and dark balance would make people “SAD”.
Where Does the Information Come From?
We aren’t the only website to take a deeper look at the affects of light on mood. It’s important to understand that most of what everyone is saying is the same. That is because most of the information comes from the same set of peer-reviewed studies on light and mood. The US National Library of Medicine and National Institutes of Health’s: Benefits of Sunlight: A Bright Spot for Human Health is a great place to look for research. Other studies include The impact of light and colour on psychological mood: a cross-cultural study of indoor work environments and more, see references below for more peer-reviewed studies on light and mood.
Science is very clear that light has a wide range of important health benefits and risks. Generally the more moderation and balance, the more benefits and fewer risks. Also, outside of specifically designed lights, sunlight is more powerful in regards to risks and benefits.
Does All Light Affect Mood, or Just Sunlight?
All light sends signals to the brain and that can affect how our body behaves. For instance serotonin and melatonin levels that affect happiness and sleep aren’t affected by sunlight as much as they are by light in general. On the other side of the coin, other benefits like the increased production of Vitamin D or endorphins have to do with specific types of ultraviolet radiation (UVR) the sun gives off UVA, UVB, or UVC.
Even something as simple as staring at your phone before bed can throw of serotonin and melatonin levels and affect circadian rhythms (your “biological clock”, your body naturally adjusts sleep patterns on an ongoing basis due to outside input of mainly light and darkness).
Is Sunlight the Same as Artificial Light?
It’s important to understand that all light is “radiation”, all light is electromagnetic waves, and all light is photons (light is both a wave and a particle). So on one level, a photon is a photon. Yet, natural sunlight is a “full spectrum” light with specific ratios of reds, yellows, and blues that all combine together to make up white sunlight. Artificial light, on the other hand, tends to contain only certain parts of the spectrum.
Light is a fickle thing. Blue light can have adverse health effects, it represses melatonin more than red and green for example. Sunlight is just as specific, the plants and animals of the earth have evolved hand-in-hand with sunlight. Plants even have specific cells (chloroplasts) that turn light into energy.
A video talking photosynthesis. Plants evolved to turn sunlight into energy, just like we do with calories in food. There are two forms of life flora and fauna, plants are flora and we are fauna. Light is important for both as you can imagine, right up there with food and water.
In theory artificial light can replace sunlight, in practice, there is no replacement for sunlight.
Is Too Much Light a Bad Thing?
When it comes to light, especially sunlight, balance is the key. Prolonged exposure to the sun’s radiation is shown to have a number of negative health risks while sunlight in moderation is shown to have nearly as many health benefits.
One can also get too much unnatural light, and that can affect mood (especially in regard to serotonin / melatonin levels). Artificial light can also increase health risks, for example, tanning in a tanning bed can cause the same skin cancer the sun can.
Does When I Get Light Matter?
Not only do different colors of light have different effects, but the timing at which we get the light can have different effects too. Light at nighttime seems to have its own set of negative health benefits. A number of studies have shown working at night with exposure to light increases the risk of cancer and other health risks like diabetes.
Can the Darkness Affect Mood?
Just like a balance of light affects mood, a balance of darkness affects mood. This is due primarily to sleep cycles and serotonin melatonin production.
The Main Reason’s Light Affects Mood
Light and especially the sun do a lot to affect our bodies. Below are the three reasons light affects mood:
Serotonin levels increase with exposure to light
The brain produces more serotonin in the light and more melatonin in the dark. Serotonin is one of the main hormones responsible for natural happiness. These pineal hormones affect our natural sleep cycles (circadian rhythms). Normally serotonin is only converted to melatonin in darkness. When we spend too much time in the dark we lack serotonin have too much melatonin. This imbalance makes us less happy and affects sleep cycles.
People with more serotonin are happier (it’s like the natural mood enhancing drug). Also, people with better sleep schedules tend to be happier too (as sleep also affects happiness).
Sunlight boosts production of Vitamin D
Unlike other essential vitamins, which must be obtained from food, vitamin D can be synthesized in the skin through exposure to UVB radiation in the sun. Low vitamin D levels may affect mood negatively according to studies, and certainly the health risks of not getting enough vitamin D won’t help lift one’s mood.
FACT: “The best-known benefit of sunlight is its ability to boost the body’s vitamin D supply; most cases of vitamin D deficiency are due to lack of outdoor sun exposure. At least 1,000 different genes governing virtually every tissue in the body are now thought to be regulated by 1,25-dihydroxyvitamin D3(1,25[OH]D), the active form of the vitamin, including several involved in calcium metabolism and neuromuscular and immune system functioning.”
Sunlight increases endorphins
Sunlight doesn’t just increase serotonin levels, it also increases blood levels of endorphins (nature’s opiate). Melanocytes in human skin express a fully functioning endorphin receptor system and the cutaneous pigmentary system is an important stress-response element of the skin.
Other Health Benefits and Risks Related to Light?
The health risks of the sun are mainly cancer from UVA radiation (which is 95 – 97% of the radiation that reaches earth). UVA penetrates the skin and acts as a mutagen causing skin cancer.
Other risks include:
- Sunburn from UVB, which also causes DNA damage and leads to cancer.
- UVR-aggravated diseases and viruses
- Those related to sleep, including the study mentioned above which equated light at night with cancer.
Other benefits include:
- UVA and UVB radiation can have direct immunosuppressive effects. (Neuropeptide substance P, Calcitonin gene-related peptide (CGRP).)
- Sun helps the skin release α-MSH, which can help repair genes and limit oxidative DNA damage.
Generally, the risks involving light revolve around damage to DNA, sleep risks, and cancer. The benefits of light revolve around mood, sleep, and immune suppression.