How Light Temperature Can Affect Your Mood And Stress Levels
In the natural world, there are three sources of light:
- The sun,
- The night sky (moon and stars) and
But for the last 100 years, humans have been using artificial light. Now, you cannot go anywhere without seeing a light bulb.
Many people don’t know that artificial light is unhealthy. We grow up thinking it is perfectly safe. But studies have shown that artificial light impacts our cognitive processes. Light (including light bulbs, computer screens, and smart phones) has a significant impact on our brains.
In this post, we will look at how different color temperatures impact on us.
Firstly, we will explain how scientists measure light. We will define an important concept called “color temperature” and explain the impact that it has on our mood and stress levels.
Secondly, we will look at how artificial light impacts the human brain at night. We will describe the impact this has on our health. We will also recommend best practices that minimize the risk.
What is color temperature?
Did you know that not all light is the same? Light can differ depending on the light source. Light comes in a variety of colors and temperatures.
If you look at a campfire, for example, you will notice a warm, orange glow emanating from the flames. But if you look at a bright spotlight, you will see a blue glow. This is because different sources of light emit different color temperatures.
Scientists have a rigorous method for measuring the color temperature of a light source, and when we talk about color temperature, we are referring to these scientific classifications.
What is Kelvin?
We measure height in centimeters or feet. We measure weight in pounds or kilograms. Similarly, we measure light in Kelvin. This is the scientific measurement unit that classifies the color temperature of a light source.
Kelvin measures a spectrum of light ranging from 1000k – 10000k.
How many types of color temperatures are there?
In terms of lighting, the three main types of color temperature are:
- Warm orange light (2000k) such as a small flame. This is the dimmest light that we use.
- Neutral white (3000k-4500k) such as the light bulbs in your kitchen. This is normal light.
- Cool blue light (6000k) such as sunlight or strong outdoor LED lighting. This is bright, intense light.
Does light affect our circadian rhythms?
Circadian rhythms govern important biological processes in the human body. The most obvious circadian rhythm is our sleep/wake cycle.
Our bodies are wired biologically to release hormones at different times. For example, when the sun sets, our brains release melatonin, which is the hormone that induces sleep. Our circadian rhythms control this process.
But our circadian rhythms affect more than just our sleep cycle. They also govern our hunger response, body temperature, and hormonal secretion.
Furthermore, light is the signal our brains use to control circadian rhythms. For example, morning sunlight will trigger a different cognitive response than a sunset in the late afternoon.
Therefore, light and color temperature have a direct impact on our body’s biological rhythms.
How does warm orange color temperature affect our mood and stress levels?
Think about sitting in a candle lit room. What type of effect would that have on your mood?
Firstly, warm orange colors (2000k – 3000k) cause relaxation. The brain perceives the dim light as a signal for either sunrise or sunset. These are both calm and peaceful times of the day.
Secondly, warm orange colors reduce stress because the brain sees dim light as a sign of inactivity or leisure.
This is one reason why restaurants often dim the lighting. It creates a more leisurely atmosphere that is conducive to eating and socializing.
But the downside to warm orange light is fatigue. The lights tend to cause drowsiness or low energy levels. So, they are not appropriate in all situations.
How neutral white color temperature affects our mood and stress levels?
Neutral white color temperatures (3000k – 4500k) are perfect for work. They mimic a typical mid-morning level of light.
Situated between warm orange and cool blue, neutral white lights avoid both extremes. They don’t make us too tired or relaxed, but they don’t hype people up either.
They are good for maintaining a stable mind state and calm emotional outlook, which is why they’re good for offices.
How cool blue color temperature affects our mood and stress levels?
Cool blue light is bright and intense. It signals clearly to the brain that it is time for work. It makes people alert and energetic. It is good for task specific lighting. Think of bright spotlights that illuminate an outdoor sporting event.
But cool blue light has some undesirable effects too. It causes the brain to release hormones such as cortisol (the hormone that causes stress).
As a result, it is important to avoid too much cool blue light. It can also cause migraines and other health problems in sensitive people.
How color temperature affects the human brain at night?
Our body is biologically adapted to the 24-hour day/night cycle. For hundreds of millions of years, the color temperature of light signaled the time of day. The mammalian brain used these signals to control circadian rhythms and other biological functions.
But then Thomas Edison invented the light bulb. By 1925, half of the American homes had electrical power. So, it has been about 100 years since artificial light became predominant.
Unfortunately, artificial light confuses your brain. If you illuminate a room after dark, the brain thinks it is daytime, and it releases daytime hormones such as cortisol. Artificial light also inhibits the release of nighttime hormones like melatonin.
The three main negative consequences of artificial light are
- Sleep disruption,
- Neurotransmitter upsets, and
- Seasonal Affective Disorder (SAD).
The effects of sleep disruption
The reason why it is bad to look at screens before bedtime is because artificial light inhibits the production of melatonin, the hormone responsible for sleep. This leads to problems such as insomnia or sleep disruption.
Since good sleep is necessary for both physical and mental health, you can imagine the catastrophic health impact that screens are having on modern people. Sleep disruption causes depression, anxiety, and mood swings.
What are the effects of neurotransmitter upsets?
Those who suffer from regular circadian disruption (such as nightshift workers) will eventually damage their neurotransmitters.
Neurotransmitters like dopamine and serotonin are responsible for our feelings of happiness and well-being. As a result, people with damaged neurotransmitters stand a higher chance of developing depressive mood disorders.
Moreover, even dim lights like a night lamp have negative effects on the brain. Artificial light is unhealthy.
What are the effects of Seasonal Affective Disorder?
Disrupted circadian rhythms also cause seasonal affective disorder (SAD). SAD is a major cause of depression and anxiety in cold countries such as Canada where the sun sets early during winter.
Some of the symptoms include:
- Low energy levels
- Changes in appetite
- Weight gain
- Suicidal thoughts
SAD does not arise only in dark, cold weather. Any exposure to abnormal artificial lights can trigger a form of SAD. It poses a serious public health risk.
What is Light therapy?
Light therapy helps correct some of the disorders associated with artificial light. It is especially helpful in treating Seasonal Affective Disorder.
The treatment involves exposure to intense white or blue light for short periods of time. It is a way to compensate for lost sunlight.
But light therapy can also help correct our circadian rhythms. The exact treatment will depend on the individual, but the basics are the same for everyone.
If artificial light disrupted your circadian rhythms (for example, due to working night shifts), a light therapist can use intense lights to restore and correct your biological clock.
The goal is to ensure the correct biological process is taking place at the correct time of day.
What are best practices for offices?
The best thing a business owner can do is limit work activity to daylight hours. If employees work late into the night, the artificial lighting will disturb their circadian rhythms.
In addition, it is possible to follow the natural day/night schedule in your office. For example, early morning lights should be dim. As the day progresses, the lighting should intensify. And midday should be the peak where you use your brightest lights.
But as the afternoon wears down, you should dim the lights again, signaling to your employee’s brains that the workday is coming to an end. This will help them to relax and unwind after a difficult day. And it will also help their psychological sense of well-being.
What should you do at home?
Although it is difficult, the best thing to do is to limit the usage of artificial lights! In the modern world, this is unthinkable. Lighting has become as natural as the sun, moon, and stars. But even if you do not eliminate artificial lights completely, it is possible to limit their usage.
It might sound silly, but maybe it is time to break out the candles. At the very least, make sure to shut off all screens, dim the lights, and relax before bedtime. Do not work on your computer late into the night because it will affect your circadian rhythms.
If you have children, try to eliminate all forms of night light. Studies show that children are twice as likely to suffer from suppressed melatonin due to artificial lighting.
Light affects our brain. Our brain affects our psychological well-being. Therefore, a smart approach to lighting both the home and office is urgent.
There is a growing body of scientific work demonstrating the negative health impact of artificial light. As the world becomes more dependent on technology, the issue of light pollution will become more important.
The crux of the issue is this: the human body has not adapted to artificial light. It still operates according to the ancient 24-hour lunar/solar cycle. But the modern world doesn’t take this biological fact into consideration. People work night shifts. Artificial light floods both the workplace and the home. Even our streets are brightly lit.
But the good news is that a few best practices and some simple preventative steps could eliminate most of the risk.