Despite being good for the environment, blue light can interfere with your sleep and even lead to health problems. People used to spend their nights in (relative) darkness because the sun was the main source of lighting until the invention of artificial lighting. Even if nights are now bright in a large portion of the planet, we essentially take for granted the simple access to all those lumens.
However, there could be a cost to all that light. The circadian rhythm, the body’s biological clock, is disrupted by light at night. Sleep is compromised. Even worse, studies indicate that it could be a factor in the development of diabetes, obesity, heart disease, and cancer.
Some studies suggest a link between exposure to light at night, such as working the night shift, to diabetes, heart disease, and obesity. That’s not proof that nighttime light exposure causes these conditions; nor is it clear why it could be bad for us.
What is blue light?
Different hues of light have different effects. It appears that blue wavelengths, which are good for you during the day because they improve mood, attentiveness, and response speeds, are most disruptive at night. Furthermore, our exposure to blue wavelengths is rising due to the widespread use of energy-efficient lights and gadgets with displays, particularly after dusk.
How light is related to sleep?
Although each person’s circadian rhythm varies somewhat, it typically lasts for 24 and a half hours. Individuals that stay up late tend to have slightly longer circadian rhythms, whereas early birds have rhythms that are less than 24 hours long. In 1981, Harvard Medical School’s Dr. Charles Czeisler demonstrated that exposure to sunshine maintains an individual’s internal clock in sync with their surroundings.
How nighttime light exposure is affecting us?
One hormone that affects circadian rhythms, melatonin, is secreted less when exposed to light. A person’s melatonin production and circadian rhythm can be disrupted by even low light levels. There’s an impact even at eight lux, which is nearly twice as bright as a night light and brighter than most table lights. One of the main causes of the widespread lack of sleep is nighttime light, and studies have connected insufficient sleep to a higher risk of depression, diabetes, and cardiovascular issues.
How blue light affecting sleep?
Any type of light can inhibit melatonin release, but blue light has a stronger effect at night. The effects of 6.5 hours of exposure to blue light were compared to those of exposure to green light of similar brightness by Harvard researchers and their colleagues. The blue light caused a two-fold increase in circadian rhythm shift (3 hours vs. 1.5 hours) and suppressed melatonin for almost twice as long as the green light.
Researchers at the University of Toronto conducted a study on blue light in which they compared the melatonin levels of individuals wearing blue-light-blocking goggles who were subjected to bright indoor light to those who were exposed to typical dull light without goggles. The theory that blue light is a strong melatonin suppressor is supported by the fact that the hormone levels were almost the same in the two groups. It also implies that if shift workers and night owls used blue light-blocking glasses, they would be able to defend themselves. Not only can cheap sunglasses with orange-tinted lenses restrict blue light, but they also block other colours, thus wearing them indoors at night is not recommended.
In the event that blue light has negative health consequences, environmental considerations and the pursuit of energy-efficient lighting may conflict with individual health. Compared to the outdated incandescent lightbulbs of our childhood, those LED and curlicue compact fluorescent lightbulbs are far more energy-efficient. However, they also frequently emit more blue light.
Fluorescent lights’ mechanics cannot be altered, however the coatings within the bulbs may be adjusted to generate a warmer, less blue light. Compared to fluorescent lights, LED lights are more energy-efficient, but they also emit some blue light. The majority of fluorescent lightbulbs generate more blue light than regular incandescent lights, but not quite as much as Cleveland’s Richard Hansler, a light researcher at John Carroll University.
