Blue Lights

You tend to hear all kinds of crazy stories (and believe them) when you are young!  When I was growing up in Indianapolis, we used to hear about a haunted house known as "The House of Blue Lights".  The house was the former residence of an eccentric local millionaire and philanthropist named Skiles Edwards Test, who died in 1964.  The story goes, at least the way that I heard it, Test kept the house decorated with blue Christmas lights all year round.  That doesn't seem too eccentric, but I also heard that he kept his deceased wife in a glass coffin inside the house, also surrounded by blue lights.  While the former story was mostly true, the latter was definitely not.  Incidentally, the house at the northeast side of Indianapolis had nothing to do with the popular boogie-woogie blues song that was released by, among others, Chuck Miller, Chuck Berry, and George Thorogood. 

Well, it was exactly the story of "The House of Blue Lights" that came to mind when I read a recently published article in The New York Times.  Journalist Caroline Hopkins Legaspi wrote an interesting article that summarizes a lot of research on the effects of blue light on sleep (see "Why do screens keep you up? It may not be the blue light.").  Smart phones primarily use blue light for their displays, and there are all kinds of studies out there suggesting that using your smart phone before going to bed is the absolute worst thing that you can do, primarily because of the adverse effects of blue light on circadian rhythm.  Blue light has a shorter wavelength and higher energy than other colors, which allows for better visibility, particularly with bright ambient light.  Blue light is naturally emitted by the sun and plays a role in regulating our body's natural sleep-wake cycle (the technical term for which is called our circadian rhythm).  Blue light helps us feel alert and awake during the day, though too much blue light at night has been reported to inhibit the release of melatonin, which is a hormone that helps us sleep.

Caroline Hopkins Legaspi suggested that the relationship between blue light and sleep is not as straightforward as we think .  She reported research by Lauren E. Hartstein, an assistant professor of psychiatry at the University of Arizona that suggests that the content of what's on the screen before bedtime is probably more important than the type of light used by the smart phone.  Some of us are perhaps more sensitive to blue light than others, while others just don't seem to be affected by blue light.  Finally, Dr. Hartstein questions whether it is appropriate to generalize findings from sleep studies performed in a laboratory versus what actually happens when those same individuals are at home.

So, what can we conclude from the available research?  First, scrolling through social media or playing video games before bedtime probably aren't helpful for our circadian rhythms.  Second, many of us just can't seem to "calm our brains" at night, and reading a book (not a suspense or murder mystery) or watching a television show (again, not a murder mystery) could actually help in these situations.  Third, if you aren't having any trouble falling asleep, even if you are checking things on your smart phone, the smart phone is probably not causing any problems.  As Dr. Hartstein says, "If you are able to fall asleep quickly, you sleep well throughout the night, and you feel rested the next day, then that's great.  You don't need to constantly adjust your behaviors."  In other words, if you want to bask in the glow of blue light, just like ole Skiles Edwards Test did, it's probably okay to do so.  Just don't put your dead wife in a glass coffin, and definitely don't listen to haunted house stories before bedtime!