This is both a short and an unoriginal post regarding sleep quality in the technological era. Many people have trouble falling asleep and staying asleep and part of the problem is the way we use technology.
I'm going to get a bit technical here, but not too much so.
(source: http://thebrightnessblog.com)
Above is an image of a color temperature scale. In layman's terms, think the "Warm" / "Cold" filter on Instagram. These are going to affect the mood of the shot. Human beings are biologically designed to be awake during the day time and asleep at night. As such there are mechanisms to regulate this. Melatonin is a sleep inducing hormone, but blue light inhibit's its release. Technology has been disruptive in many areas including human sleep.
"The light from our devices is “short-wavelength-enriched,” meaning it has a higher concentration of blue light than natural
light—and blue light affects levels of the sleep-inducing hormone melatonin more than any other wavelength."
There are several apps to help this process, which I just started using. There are a suite of apps, but they all basically alter the color temperature of the light on your device from blue (artificial) to a yellow (natural). F.lux is a great app for the Mac and Twilight works excellently on my Android.
However, there are others out there. For f.lux, just Google it and you'll be taken to the website and Twilight is just a Google Play Store search away. Both are free and both work well.
Happy Sleeping!