What you might not be aware of, is the emitting of bright blue light that your smartphone does in order for you to be able to read in daylight everything that is on the screen. But, this light cannot be adjust or turned off any hour you want; it emits all the time as well as your laptop, television and other devices around you. The issue may be that this light, which imitates the brilliance of the sun, confuses your brain under considering it is daytime, although it is quite dark in the night. As a result your brain no longer produces melatonin, a hormone which influences sleeping, and can prevent you from falling asleep. The experts advise to shut down every screen near you two hours preceding lying down you bed.