What is Blue Light?
The human eye can take in light, or electromagnetic waves with wavelengths from 400-750 nanometers. Blue light has a wavelength from 380nm to 500nm, so it is some of the shortest wavelength and high energy light we see. We often intake blue light from screens, whether it be your smartphone or laptop or TV.
New BYU Study
Recently, BYU published a study on the effects of blue light for sleeping. It experimented with Apple’s iOS feature known as Night Shift which uses warmer tones as opposed to blue light after sunset. It is advertised as helping with users sleeping better when using the phone with Night Shift at night. In order to test these claims, BYU professor Chad Jensen compared the sleep of individuals with accelerometers. These participants were grouped into three different categories: those who used their phone at night with the Night Shift feature, those who used their phone at night without the feature, and those who did not use their phone at night.
The study included 167 emerging adults whose ages ranged from 18 to 24 and have daily cell phone usage. They were prompted to spend at least eight hours in bed each night and their cell phone use was also monitored through an app.
In the results of the study, Jensen concluded that “there were no differences across the three groups … Night Shift is not superior to using your phone without Night Shift or even using no phone at all.” The study was based on multiple metrics, including the sleep duration, quality, wake after sleep onset, and the amount of time it took to fall asleep initially. One interesting conclusion is that the individuals who did not use a phone at all before going to bed experienced superior sleep quality compared to the other individuals. In conclusion, the Night Shift feature on your phone will help make your screen darker, but it alone will not help you with falling or staying asleep.