Many people read to help them fall asleep. However, technology has caused a change in how reading at bedtime affects sleep. People who used to read hard copy print books are now reading from tablets. Reading on electronic devices before bedtime can affect circadian rhythm, making it more difficult to fall sleep and becoming alert in the mornings. It has long been known that watching TV, working on a computer, and other activities involving artificial light in the evening can disrupt sleep patterns.
The type of light that adversely affects sleep is “blue light,” the type of light that many backlit devices emit. It is a powerful suppressor of the release of melatonin, the hormone that helps bring on sleep. Having this type of light shine directly in your eyes when reading from an electronic device can have an adverse effect on your sleep. Studies funded by NIH (National Institutes of Health) have shown that reading from an electronic device increased the time it took participants to fall asleep by 10 minutes. Participants had less rapid-eye movement, and blood tests of melatonin indicated their circadian rhythms were delayed as much as an hour. Participants also reported that it took longer to become fully alert in the mornings if they read from a tablet the night before.
If you are having sleep difficulties, consider putting down your tablet at bed time and open a book instead! It just might make a difference for you.