Study Shows How to Use Smartphone at Night without Disrupting Sleep

Ever since you've got that shiny new smartphone or tablet, have you noticed whether you've been getting sufficient sleep? These devices inadvertently affect the quality and duration of a person's sleep. This is because smartphones and tablets have bright light emitting diodes, which interfere with melatonin, a hormone that controls the sleep-wake cycle.

A new Mayo Clinic study, however, offers an alternative way to check mobile devices without hampering one's sleep. The researchers suggest that dimming the brightness settings of the smartphone or tablet and holding the device at a distance of at least 14 inches from the face while using it reduced the risk of the brightness interfering with melatonin and affecting sleep.

"There's a lot of concern about using mobile devices and that prompted me to wonder, are they always a negative factor for sleep?" says co-author Lois Krahn, M.D., a psychiatrist and sleep expert at Mayo Clinic in Scottsdale, Ariz.. "We found that only at the highest setting was the light over a conservative threshold that might affect melatonin levels. If it's at the mid setting or at a low setting it's bright enough to use."

To prove their finding, researchers experimented with two tablets, iPad1 and iPad3 with retinal display, and a smartphone, iPhone 4 in a dark room. They used a sensitive light meter to measure the light that was emitted from the tablets and smartphone. The light that was emitted was measured right from 0 inches to 14 inches away from a user's face.

The researchers noticed that when the brightness setting was lowered and the device was placed just over a foot from the user's face, the risk of the light to suppress melatonin secretion was reduced, and the risk of disrupting sleep was lowered.

The new research was one among Mayo Clinic studies being presented at SLEEP 2013, the Associated Professional Sleep Societies annual meeting in Baltimore.