If you want to improve your sleep, a new report published in the journal Nature on Wednesday advises shutting off your tablet well before bedtime.
 

Night-time exposure to LED rays illuminating from tablets, computers, TVs, and smartphones can disrupt your body's natural rhythms, and raise your risk for not only sleep loss but health problems, the report said. Artificial light can prevent quality sleep by slowing the activity of neurons that induce sleep, activating those for wakefulness, and suppressing the sleep hormone melatonin.

"Technology has effectively decoupled us from the natural 24-hour day to which our bodies evolved, driving us to go to bed later," wrote lead author Dr. Charles Czeisler, of Harvard Medical School. "And we use caffeine in the morning to rise as early as we ever did, putting the squeeze on sleep."

"Many people are still checking email, doing homework or watching TV at midnight, with hardly a clue that it is the middle of the solar night," he added.

Czeisler claims that a decline in the number of hours slept per night brings a host of health risks, including obesity, diabetes, depression, and heart disease, as well as concentration problems in children.

A study from Rensselaer Polytechnic Institute's Lighting Research Center found that looking at a backlit screen, like those on iPads and other tablets, can lead to sleeplessness. The findings were published last September in a recent issue of journal Applied Ergonomics.