Blue light is a range of light in the visible light spectrum. It contains the highest amount of energy between 400 to 495 nm. Although it can be considered environmentally friendly, it can impact our sleep and can potentially cause illnesses or diseases. The sun used to be the only source of light until people created alternative sources of light during the night time. People used to spend their evenings in darkness. Now evenings are illuminated, and we have access to all the lumens. This brought up the need for blue light glasses.
During the night, light throws our body’s biological clock (circadian rhythm) out of whack. The circadian rhythm is affected by lightness and darkness. When it’s dark at night, our eyes will send a signal to our brain that it’s already time to feel tired. In return, our bran will send a signal to our body to release melatonin. When our body releases melatonin, it feels tired. Overexposure to blue light affects the circadian rhythm. This causes people to have problems with sleeping at night. But that’s not the only dilemma we’re facing. Research shows that blue light can contribute to diabetes, cancer, obesity, and heart disease.
What is blue light?
All colors have different effects. Blue wavelengths are beneficial to our body during the day. That’s because they boost our reaction times, attention, and mood. However, this is the most disruptive at night. You may not be aware of this but we are easily exposed to blue light regardless of the time. That’s because of the proliferation of electronic gadgets like smartphones, tablets, TVs, and other devices. These devices increase our exposure to blue light wavelengths, especially after sunset.
Light and Circadian Rhythm
Everyone has different circadian rhythms. At the same time, the average length for it is 24 and a quarter hours. People who usually stay up late have longer circadian rhythms. Those who sleep early fall short of 24 hours. This is because daylight is what keeps an individual’s internal clock to be aligned with the environment.
Is nighttime blue light exposure bad?
There have been a lot of studies that proved a connection between blue light exposure at night to some illnesses and diseases. Studies show that people who work at night and are exposed to blue light are at risk of diseases like diabetes, cancer, heart disease, and even obesity. There isn’t a direct proof that nighttime exposure to blue light can cause such conditions. In addition to that, it doesn’t give us a clear link as to why blue light is bad for us at night. But one thing is for sure. Being exposed to blue light can suppress the secretion of melatonin. Melatonin is a hormone which influences the circadian rhythm. The lower the melatonin level is, the more there is a risk for an individual to have cancer.
A study from Harvard University explained the possible connection of blue light to obesity and diabetes. The researchers put 10 individuals on a schedule who gradually shifted the timing of their circadian rhythm. Because of this, their blood sugar levels have increased. This threw them into the pre-diabetic state. Their leptin levels went down, too. (Leptin is a hormone which makes people feel full after a meal)
Dim light can also interfere with melatonin secretion and a person’s circadian rhythm. Even a low level of brightness that is exceeded by most table lamps can impact a person’s sleep. That explains why there are so many people who don’t get enough sleep with the lights on.
What are the effects of blue light?
Light of any kind can suppress the secretion of melatonin. But blue light can do so, too, and it’s even more powerful. Researchers in Harvard conducted an experiment to compare the effects of being exposed to blue and green light for 6.5 hours. The experiment showed that blue light was able to suppress about twice as long as the green light. It also shifted the circadian rhythms by twice as much as the green light.
Researchers at the University of Toronto also made an experiment to compare the levels of melatonin. This involved people who are exposed to bright indoor light wearing blue light glasses and people who are exposed to regular dim light without the glasses. The levels of hormones were the same in both groups. The experiment has proven that blue light is a suppressor of melatonin secretion. The experiment also suggested that night shift workers can protect themselves if they wore blue light glasses.
Why do we need blue light glasses?
If the blue light level does have dangerous effects on our health, then our quest for energy-efficient lighting is at odds with our personal health. Most of the light bulbs we are using today are energy-efficient. At the same, they produce more blue light compared to the incandescent light bulbs that we grew up with.
We cannot change the physics on how fluorescent lights are made, but we can change the coatings inside. We can change it in such a way that it can produce lesser blue light. LED lights are more energy-efficient than fluorescent lights but they produce more amount of blue light. Even ordinary incandescent lights produce blue light, although they produce less than most fluorescent light bulbs do.
How do we protect ourselves from blue light at night?
Here are some tips that we can use in order to protect ourselves from the harmful blue light levels.
- Use dim red lights. During the night, it is better to use dim red lights. Red light has the lowest power to affect circadian rhythm and to suppress melatonin.
- For people working on a night shift, make sure to use or install an app that can filter blue or green light. You can also use blue light glasses to protect your eyes.
- For people who are using their phone or other electronic gadgets at night, make sure to enable blue light filter. Newer smartphones have this feature so make sure to use it.
- Be sure to avoid looking at bright screens two or three hours before going to bed.
- Be exposed to bright light during the daytime. This will boost alertness and mood during daylight. It will also boost the ability to sleep during night time.