The problem with artificial light
All artificial light, including LEDs, fluorescent bulbs and incandescent bulbs, can interrupt normal sleep patterns. The body's biological clock works in rhythms that are set by the amount of light and dark the body is exposed to. This is called the circadian rhythm. Circadian rhythms control the timing of many physiological processes. They determine sleeping and feeding patterns, as well as brain activity, hormone production and cell regeneration.
Other studies have found that blue wavelengths suppress delta brainwaves, which induce sleep, and boost alpha wavelengths, which create alertness. To get better sleep, it would be best to stop using artificial light altogether, but that isn't possible in modern times.
"To prevent sleeping problems, avoid any exposure to blue light 30 to 60 minutes prior to bed. That means, no TV, tablets, computers or smart phones," said Dr. Robert Oexman, director of the Sleep to Live Institute. "Ideally, you want your environment to be dimly lit so your body can start naturally producing melatonin."