Sunlight is the largest source of blue light on the earth. However, electronic screens, such as televisions, smartphones, computers, all emit artificial blue lights. Blue light is a part of the visible light spectrum that has the shortest wavelength. Among all types of visible light, blue light is considered to have a close relationship with the changes of the circadian rhythm.
Statistics have shown that nine out of ten Americans reach for an electronic device shortly before bedtime for replying to messages, browsing videos, reading e-books, etc. All these can be an invitation for insomnia. Blue lights from electronic devices may boost your alertness and mental sharpness, which lead to low sleep quality.
How does blue light affect sleep?
The circadian rhythm was formed in the process of human evolution. It helps our bodies realize and keep a routine of the best time to carry out essential daily functions. Back in the days when we still need fire to illuminate, light is already the most important factor in forming circadian rhythms. Our ancestors rely on sunrise and sunset to know when to eat, hunt and rest. However, with the development of science and technology, people are exposed to an increasing amount of light during their whole day, blue light in particular.
Melatonin is no stranger to people with insomnia. When you have difficulty sleeping and visit the doctors for help, they always prescribe some melatonin-containing drugs. In fact, blue light is the evil that suppresses the release of melatonin in our body, which is a hormone that makes us feel drowsy. The level of melatonin naturally starts to rise about two hours before we fall asleep, and it reminds us that it’s time to sleep. Melatonin will remain at its highest level while we’re sleeping.
Human brains cannot distinguish between blue lights from the sun and blue lights from electronic devices. Therefore, blue light at night will trick our brains into thinking it is still daytime. Excessive exposure to blue lights disrupts circadian rhythms and leaves us feeling alert instead of tired. The interruption of the natural production of melatonin also inhibits the normal functioning of the human body’s sleep-promoting mechanism.
Ways to manage blue lights
The simplest and most effective way to reduce your exposure to blue light is to turn off your electronics before bedtime. Other ways include:
Dim the brightness on your devices: Shift your screens over to night mode or dark mode. This small change can help reduce blue light exposure.
Install blue light filtering apps: These applications filter a lot of blue light from reaching your eyes.
Give priority to red light bulbs: Try some lamps that do not emit blue light. Red or orange lamps are good choices because they are the colors that least affect your circadian rhythm.
Improve your sleeping environment: If there are light sources in your bedroom that you can’t dim or turn off, an eye mask will help you block them out.