By now, you probably have already read somewhere or been told by someone that it’s not good to be using your phone in your bed. Perhaps you’ve even tried cutting back on your in-bed screen time, but haven’t noticed much difference or found it too hard. After all, your phone is your bedside alarm clock… as well as your ebook reader, and your anti-boredom device, and your social network portal, and your emergency communications system… It’s no wonder that people have such a difficult time unplugging from it, even in bed. So exactly how bad is it? And, do you really need to give it up?
“Blue” light is disruptive to sleep
There’s now wide scientific consensus that the type of light emitted from our digital devices (smartphones, tablets, computers, etc.) is particularly disruptive to our body’s regulation of sleep, and it has to do with light wavelengths and your circadian rhythm. Up until the advent of electricity, humans have relied on the sun’s schedule to sleep and rise, and we now know that our bodies are biologically attuned to sunlight to keep our circadian rhythms aligned with the earth’s day and night cycle. With the invention of electricity and artificial lighting, we have effectively been able to extend the daylight hours, causing disruption to the circadian rhythm.
In fact, research in recent years has found the exact mechanism that gets disrupted – the secretion of melatonin, a sleep-related hormone, gets suppressed with light exposure and causes the onset of sleepiness to become delayed. This effect is most pronounced for light with shorter wavelengths, which means light on the blue end of the spectrum. And that, it turns out, is exactly the type of light emitted by our digital devices: smartphones, tablets, laptops, TVs, and other LCD screens. Thus the brighter the screen and the closer to bedtime your use is, the more likely it is to disrupt your sleep that night as well as your circadian rhythm in the longer term.