What is blue light? Taking you back to grade school, a rainbow shows the different colors that make up white light, ranging from red at one end all the way to violet at the other. Red has a longer wavelength and is less easily scattered whereas blue has a shorter one and is more easily scattered. That’s why the sky generally appears blue.
Ok, but what does it do? Blue light is awesome during the daytime because it can boost attention, mood and reaction times. It’s not so great at bedtime. Prior to electronic screens, humans essentially evolved to be dependent on the sun for this type of stimulation, and it’s why for however long humans have been around, people tend to be more focused during the day and sleep at night. Now, with the advent of tablets and cell phones, some people can’t even get out of bed until they get their electronic fix and the blue light that wakes them up.
Um, is that a problem? It may not be the end of the world to play on your phone a minute or two before getting up, but not being able to sleep at night due to screen time definitely isn’t a good thing. Blue light decreases melatonin levels, which are responsible for your circadian rhythm, meaning that falling asleep can be harder. In some cases much harder. Given that just over 2/3 of the U.S. has trouble sleeping at least one night a week, it’s not unreasonable to think that there may be a correlation, especially as this is nearly an identical number to those in the U.S. with a smart phone. Those sleep struggles can lead to obesity, heart disease, decreased libido, inhibited immune system, and even contribute to some types of cancer.
Yeah, but I’m not getting rid of my smart phone, so what can I do? In an ideal world, stopping screen time for at least a few hours before bed is a good idea. In a practical world, screen settings with warm light or blue light-filtering glasses/screen protectors may provide some benefit. While some studies suggest these measures can help prevent some of the melatonin decrease associated with sleep disturbances, the data is mixed, so it’s unclear if these measures really make things better or just make us feel better about trying to do something. The bottom line is that light is good during the day, and sleep is good at night 😊