The National Sleep Foundation tested the sleep patterns of about 1,500 adults. Ninety-five percent surveyed reported using some type of electronic device within one hour of bedtime several nights a week.
Devices include televisions, computers, video games or cell phones.
Researchers say the gadgets emit light, which can suppress the sleep promoting hormone melatonin, making it harder to fall asleep.
The study suggests active technologies are worse for sleep because of the psychological effect of being stimulated right before bedtime.