Do you have a smart phone? Tablet? Laptop? Like most of us, you probably have at least two out of three of those devices, and while science keeps telling us that screens are interfering with our lives, a new study suggests it may be even worse than we though.

The Brigham and Women's Hospital in Boston published a study in the Proceedings of the National Academy of Sciences on Monday (December 29) which found that using devices like iPads to read right before bed makes it harder for us to fall asleep.

But not only that, it also impacts your levels of sleepiness and alertness on the following day too.

"We know from previous work that light from screens in the evening alters sleepiness and alertness, and suppresses melatonin levels," Dr. Anne-Marie Chang who was a co-author on the study and is an associate neuroscientist in BWH’s Division of Sleep and Circadian Disorders, told The Huffington Post. "This study shows comprehensive results of a direct comparison between reading with a light-emitting device and reading a printed book and the consequences on sleep."

The two-week study included twelve participants who read from both an iPad and a book for four hours right before bed, alternating which type of reading material the participants began with. iPad readers took longer to fall asleep, but also reported feeling less sleepy and had shorter REM cycles than book readers.

Chang went on to point out how sleep deprivation can be linked to very serious health problems like obesity, diabetes, and even cardiovascular disease. So the solution seems clear: read an actual, printed book before bed instead of using a screen—your health depends on it!

But if you absolutely must use screens before bed, Chang has a few tips.

"The best recommendation (although not the most popular) would be to avoid use of light-emitting screens before bedtime," Dr. Chang said. "For those who must use computers or other light-emitting devices in the evening, software or other technology that filters out the blue light may help."