May 07, 2021 17:00:00

It turns out that the night mode of the smartphone does not contribute to improving the quality of sleep at all

It is known that

the quality of sleep deteriorates when using a digital terminal at night, and the screens such as 'Night Shift ' installed in iOS and 'Night Mode ' installed in Android are changed to warm colors. It has been thought that the ability to change can be used to reduce the deterioration of sleep quality. However, a study of 167 subjects found that Night Shift on iOS had no effect on sleep.

Does iPhone night shift mitigate negative effects of smartphone use on sleep outcomes in emerging adults? --ScienceDirect
https://www.sciencedirect.com/science/article/abs/pii/S2352721821000607

Is Night Shift really helping you sleep better?
https://news.byu.edu/intellect/is-night-shift-really-helping-you-sleep-better

Night Shift is a function added in 'iOS 9.3' released in March 2016, and you can automatically change the screen display color to warm colors at the specified time. In the latest version of iOS 14.5.1 at the time of writing, the Night Shift settings screen said, 'It may help you sleep well at night.'

A research team at Brigham Young University asked 167 subjects aged 18 to 24 years to 'group without an iPhone before bedtime' and 'iPhone with Night Shift disabled before bedtime' to see the effect of Night Shift on sleep. Divided into 3 groups, 'Group to use' and 'Group to use iPhone with Night Shift enabled before going to bed', and attached an accelerometer to the subject's arm, 'Sleep time', 'Sleep quality', 'Awakening during sleep', 'Sleep onset' I investigated 'the time it took'.

As a result of the survey, no significant difference was confirmed in the sleep of the three groups. Therefore, the research team divided the subjects into 'a group that slept an average of 7 hours or more' and 'a group that slept an average of 6 hours or less' and analyzed them. As a result, although there was no significant difference in the 'group that slept on average 6 hours or less', the iPhone in the 'group that slept on average 7 hours or more' regardless of whether Night Shift was enabled or disabled. It turns out that the sleep quality of the group with the iPhone is worse than that of the group without the iPhone.

From these results, the research team believes that 'not only the blue light reduced by Night Shift, but also the psychological effects of operations such as scrolling the screen and displaying / posting text also affect sleep.'

'If you're very tired, your sleep pressure will be so high that you can fall asleep regardless of what you did just before you went to bed,' said Chad Jensen, a member of the research team. I will.