It’s late. As usual, you are playing your favorite online game on your smartphone. You play for an hour. Two hours. Three. You do not feel sleepy. The game is too exciting to stop. Or is it? According to some researchers at University of Houston, the bigger culprit to blame could be the bright blue glow emitting from your phone tricking the brain into thinking it is daytime.
“We believed that blocking blue light would improve sleep quality and duration.” ~Lisa Ostrin, lead researcher and an assistant professor at College of Optometry, University of Houston
In their research, the melatonin (hormone released by the pineal gland in the brain to signal that it’s time to sleep) level of study participants recorded a 58% jump just by putting on a pair of cheap orange sunglasses before bedtime while still going on their normal bedtime routine. Furthermore, from changing the visual hue from blue to orange (think sunset), the group reported drifting off earlier and more easily, even to the extend of staying asleep longer. Now, that is certainly good news for a nation where reportedly one in three are sleep deprived.
The study was completed in early 2016 and its findings published in June in Ophthalmic & Physiological Optics, the national medical journal of the college of optometrists.
Twenty-one volunteer participants, aged between 18 and 40, pledged they would wear the tinted glasses for two weeks a few hours before going to bed. Most importantly, they would continue their usual routines of reading phones or tablets, watching television or working on computers while wearing the glasses.
To help understand their sleeping patterns better, the participants also wore specialised smart watches to bed to monitor sleep duration and patterns. Although similar studies have been conducted in sleep labs, Ostrin wanted hers to replicate the way people live as closely as possible. Each night and again in the morning the participants underwent saliva swabs to measure melatonin levels.
One of the participants, Krista Beach, a 38-year-old post-doctoral student said, “I’ve had poor sleep quality since I was a teenager.” By wearing the glasses, she said she was able to fall asleep earlier. In the end she found herself getting sleepier earlier, which meant she slept more.
Knowing the link between blue-wavelength light and sleep disruption, Ostrin wanted to objectively quantify it. One of the answers lies in the recent discovery of a third sensory element in the eyes called intrinsically photosensitive retinal ganglion cells. The third sensor signals light changes. It is the job of those sensors to send a message to the brain to start or stop the pineal gland. They have also been found to be the most sensitive to blue light.
Although most personal device screens may appear white, they are usually illuminated with blue LED lights, which were found to be more energy efficient and easier to see. This breakthrough that helps people work better and longer also worsened their sleep according to Ostrin. Therefore, the next time you need to sleep early but can’t, do not resort to screen time. Instead, the traditional method of drinking a cup of warm milk would do the trick.