What better way to end the evening than scrolling through the same three apps you’ve spent all day staring at?
If you’re familiar with this nighttime ritual, you might be aware of the night mode functions available on smartphones that turn your screen from a colder blue-tinged light to a warmer yellow hue. The idea is that the blue light appears similar to daylight and inhibits the production of melatonin, the hormone associated with control of the sleep–wake cycle. Yellow-orange light, on the other hand, mimics the color of sundown and doesn't have as much of an inhibitory effect on melatonin production, promoting a healthier night's sleep.
But does this night mode feature actually work? It doesn’t appear so, according to new research.
Contrary to previous studies, recent research argues that the nighttime functions of smartphone screens have very little influence on sleep quality. If you sleep a healthy amount, however, abstaining from smartphone scrolling before bed might help.
As reported in the journal Sleep Health earlier this month, scientists at Brigham Young University and Cincinnati Children's Hospital Medical Center gathered 167 college students and asked them to spend at least eight hours in bed while wearing an accelerometer on their wrist to monitor their sleep activity.
The researchers split the sample into two separate groups: those who averaged about seven hours of sleep (closer to the recommended amount), and others that slept less than six hours each night (generally considered to be too little sleep). Participants were then randomly assigned to one of three conditions for the hour before bedtime for seven consecutive nights: iPhone use with Night Shift enabled; iPhone use with Night Shift disabled; and no phone use.
For those that got around seven hours of sleep – which is closer to the recommended eight to nine hours a night – there was a slight improvement of sleep quality if they did not use their phone before bed compared to those with normal phone use as well as using Night Shift.
"Night Shift is not superior to using your phone without Night Shift or even using no phone at all," Professor Chad Jensen, study author and psychologist from Brigham Young University, said in a statement.
For the six-hour group, who generally get less sleep, there were no differences in sleep quality based on whether the participants used Night Shift or not.
"This suggests that when you are super tired you fall asleep no matter what you did just before bed," explained Jensen. "The sleep pressure is so high there is really no effect of what happens before bedtime."
According to the researchers, it’s largely irrelevant whether your phone is beaming out harsh blue light or softer yellow light. It appears that the psychological requirement of messaging and engaging with content on social media is actually the thing that keeps your brain buzzing and can potentially affect sleep quality.
In other words, if you want to get a better night's sleep, it's not a bad idea to totally stop using your smartphone in the hours before you hit the sack.