Researchers: E-readers negatively impact sleep

CHICAGO (WLS) -- E-readers have become increasingly popular in recent years, but a recent study may keep users awake at night.

New research released Monday shows that reading tablets may be disrupting your sleep.

Harvard researchers studied 12 volunteers for two weeks in a controlled setting to compare how e-readers affected sleep cycles compared to traditional paper books.

Researchers found that when subjects used an e-reader for a few hours before bed, they had more trouble getting to sleep and more sleepiness in the morning. Blood tests even revealed they had lower levels of the hormone melatonin, which helps regulate sleep and wake cycles.

The researchers think the short-wavelength blueish light from e-readers may be to blame. Blue-wave light from the sun signals our bodies to wake up.