Our love affair with our devices is so pervasive that there are even memes about looking at our phones in bed. And catching up with everyone on social media can be a tempting way to clock off for the night. But there’s a worrying cost to our 21st-century obsession with staying connected 24/7. There have been many studies verifying the link between exposure to blue light and the suppression of melatonin, a hormone that is crucial for helping us fall asleep.
The body’s inner sundial
Your circadian rhythm is like an internal, biological timetable that affects a range of bodily functions, including wakefulness, hunger, and your body’s self-repair cycle. Evolution has tuned your body to rely on information from the environment to keep this rhythm in sync with optimal times during the day when it is best for you to be alert—on the lookout for risks and opportunities—and when it is time to rest and digest.
During daylight hours, sunlight suppresses the production of melatonin, known as the sleep hormone. In this regard, we are most sensitive to wavelengths of light in the band of 459-480nm (nanometres), which correspond to the blue end of the spectrum. The reason why we feel awake and alert during daytime is because blue wavelengths form a major part of sunlight’s visible spectrum. By default, high-strength LEDs (light-emitting diodes) emit light that falls right within this range, but ‘white’ ones have a yellow filter on the light-emitting semiconductor that tricks our eyes into seeing the light coming from them as white.
This LED technology is used to power much of the artificial lighting in our homes—ranging from downlights to retrofit LED tubes that can be retrofitted as strip lighting—as well as many of the screens in our homes. Many ambient lights that use CFL (compact fluorescent light) fittings also emit daylight-spectrum frequencies, which are great for working spaces such as laundries or kitchens. But a better choice for living areas are CFLs labeled ‘warm white’, which filter out much of the blue end of the spectrum and emit a softer, more candle-colored hue instead.
Get back on schedule
Regardless of where the bluish glow is coming from, the net effect is that it’s stalling our internal timetable, and keeping us wired and alert at a time when we should be growing drowsy and feeling naturally tired. The simplest solution is not to use TVs, laptops, and other devices with backlit screens for two hours before bedtime. But where’s the fun in that? As an alternative, follow these easy tips for reducing the effects of blue light, and you will be more likely to drift off to sleep more swiftly and easily.
- Catch some rays: Neither blue light nor bright light are bad for you; it’s just that exposure to them during the evening will make it harder for you to sleep. One simple way to counteract the effects of blue light in the evening is to spend some time exposed to natural sunlight during the day. The intensity and wavelengths can do you a world of good—even if you just take a half-hour lunch break outside, this will still be a big improvement on spending the entire day in an office filled with artificial lighting. Exposure to sunlight helps produce serotonin, which turns into melatonin at night, which helps us to nod off at night.
- Shift the spectrum: Applications such as f.lux change your screen’s brightness and color output to reduce blue light automatically depending on what time of day it is. The software is available for Mac, Windows, iOS, and Android.
- Get set for sleep: Many devices offer a ‘night mode’ option in the settings, or can be set to automatically adjust the intensity and hue of the light they emit depending on the ambient light they detect.
- Feast your eyes: It may seem a bit kooky, but eyewear designed to block blue light is a highly effective option. An important bonus of goggles is that they also filter out ambient shades of blue, for example from overhead CFLs.
- Screen it out: If the lights in your bedroom already have a ‘warm white’ color temperature, or they’re dimmable, another option is to use a physical filter that can block blue light from your smartphone or laptop.
- Opt for lateral thinking: The screen of a latest-generation device such as a Kindle Paperwhite is not actually backlit. On a tablet or laptop, the light is projected through the screen and enters our eyes at a relatively high intensity, even when the screen is dim. More advanced e-readers use LEDs that are pointed inward at the surface of the screen itself, creating a visible contrast between the light and dark areas.
Play it smart to get the rest you need
If you’re finding it difficult to fall asleep at night, it’s quite possible that blue light is a factor. Reducing its effects is an essential part in helping you drift off into a peaceful slumber, but it won’t fix everything. If you are going to use devices before bedtime, it is preferable to use your devices for activities that calm you down, rather than rev you up. Opt for playing sudoku, looking at nature pins or reading a blog rather than watching trailers for horror movies or getting into political debates on Twitter.
Try these easy tips for yourself and you can enjoy the best of both worlds. If you’re smart about it, you can still wind down with the devices you love, and then slip peacefully out of evening’s harbor when it’s time to set sail for the land of dreams.