The light from smart phones and tablets contains much of the blue light that suppresses the sleep hormone melatonin causing sleep to be delayed. The blue light in daylight is both necessary and helpful during the daytime, but the opposite at night.
This study is specifically about teenagers (15-17), and is made in continuation of other similar analyzes. Here it is indicated that the problem is even greater for teenagers than it is for adults.
The body starts to produce the sleep hormone, Melatonine, appr. 2 hours before we are going to sleep. The process is controlled by the surrounding light. In the evening when the daylight disappears (the light turns less blue and eventually disappear) the body starts the process. If you expose yourself to a smartphone for 1 or 2 hours before bedtime, Melatonine production is suppressed with up to 38%. For many, the consequence is that it becomes much harder to fall asleep and that the subsequent sleep quality is lower than it normally is.
Gradually, most smartphones and their operating systems have the ability to turn nightly views (eg Night Shift to iOs or Twilight to Android) either automatically or manually. Thus, the screen changes color to a more reddish shade that does not affect the body in the same way.
In Needlite, we have built in a function that reminds you to turn off the lamps a few hours before the scheduled bedtime, so you can enjoy the daylight during daytime, but also for a good night's sleep.
The information will include from this study:
"The impact of self-luminous displays on evening melatonin levels"
M. Figueiro, MS. Rea; Lighting Research Center, Rensselaer Polytehnic Institute, Troy, NY, USA.
Read the study here