If you're not getting enough sleep, your cell phone may be the reason.
Researchers from Sweden and the U.S. say people who use their phones before bed have a harder time falling into a deep sleep and staying there.
They believe the radiation may interfere with the brain's normal rhythms.
Scientists are especially concerned for children and teens that are more likely to use their phones late at night the London Independent reports
One industry group says the results are inconclusive, but some experts recommend using a land line for late night calls.