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About 95 percent of Americans use an electronic device within one hour of going to sleep, according to a National Sleep Foundation poll. Furthermore, nearly all adults (89 percent) and the majority of children (75 percent) have at least one electronic device, such as a television, tablet, or smartphone, in their bedrooms.1

This has a major implication on the quality of your sleep, in ways you might not even imagine. Certainly, such devices can keep you awake by making noises, but they also interfere with your sleep-wake cycle, or circadian rhythm, in far more insidious, and damaging, ways.

Light from Electronic Gadgets Interferes with Your Sleep

The quality of your sleep has a lot to do with light, both outdoor and indoor lighting, because it serves as the major synchronizer of your master clock. This master clock is a group of cells in your brain called the suprachiasmatic nuclei (SCN).

As a group, these nuclei synchronize to the light-dark cycle of your environment when light enters your eye. You also have other biological clocks throughout your body, and those clocks subsequently synchronize to your master clock.

In the non-artificial light environment of our historical past, people experienced greater light exposure only during the day between when the sun rose and when it set. Now with the advent of the light bulb, artificial light, high-definition televisions, and any number of lighted electronic gadgets, we’re exposed to a lot more light over a 24-hour period, and a lot less darkness.

This creates a very novel situation for your internal time keeping and the biological pace setting mechanisms of your body; in other words, your circadian rhythms. As reported by the National Sleep Foundation:2

“There is robust scientific data documenting the role of light in promoting wakefulness. Photoreceptors in the retina sense light and dark, signaling our brain about the status of the outside world and aligning our circadian rhythms (centered in a small region of the hypothalamus called the suprachiasmatic nucleus) to the external day-night cycle.

This signaling of light and dark helps us to be alert in the morning and be able to fall asleep at the appropriate time at night. The power of light as an alerting agent is easily conceptualized when we think of the sun, but may be more difficult to appreciate when considering the light emitted from a tablet or smartphone.”