Light from self-luminous electronic gadgets `can inhibit sleep`

Updated: Aug 29, 2012, 11:12 AM IST

London: Using mobile phones and tablets with a backlit display for just two hours before bed can cause sleep problems, researchers say.

IN the new study, researchers from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute believe the displays cause melatonin suppression.

Melatonin is the chemical that controls our body clock – it is a “timing messenger”, signalling night-time information throughout the body.

Since they believe teens are particularly susceptible to the problem, they made them wear special goggles to monitor the effects in the new study.

“Our study shows that a two-hour exposure to light from self-luminous electronic displays can suppress melatonin by about 22 percent,” the Daily Mail quoted Mariana Figueiro as saying.

Melatonin is a hormone produced by the pineal gland at night and under conditions of darkness and exposure to light at night, especially short-wavelength light, can slow or even cease melatonin production, interrupting sleep.

Suppression of melatonin by light at night resulting in circadian disruption has been implicated in sleep disturbances, increased risk for diabetes and obesity, as well as increased risk for more serious diseases, such as breast cancer if it occurs for many consecutive years, such as in nightshift workers.

“Stimulating the human circadian system to this level may affect sleep in those using the devices prior to bedtime,” Figueiro said.

The research team tested the effects of self-luminous tablets on melatonin suppression.

In order to simulate typical usage of these devices, 13 individuals used self-luminous tablets to read, play games, and watch movies.

The actual melatonin suppression value after 60 minutes was very similar to those estimated for spending an hour in sunlight and was not deemed significant.

However, after a two-hour exposure there was significant suppression.

“Technology developments have led to bigger and brighter televisions, computer screens, and cell phones,” Brittany Wood said.

“To produce white light, these electronic devices must emit light at short wavelengths, which makes them potential sources for suppressing or delaying the onset of melatonin in the evening, reducing sleep duration and disrupting sleep.

“This is particularly worrisome in populations such as young adults and adolescents, who already tend to be night owls,” she added.