updated 10/23/2012 8:45:22 AM ET 2012-10-23T12:45:22

Even with the shift to standard time this Sunday (Nov. 4), the days will continue shortening, making it even tougher to get up. Less light signals the body it's still night. But early morning exposure to an iPad, computer or other backlit device could help ease the seasonal transition, according to a study from the Rensselaer Polytechnic Institute in New York.

In addition to overcoming grogginess, researchers at the Institute's Lighting Research Center found that exposure to morning short-wavelength “blue” light — the shorter wavelengths emitted by most device displays — has the potential to help sleep-deprived adolescents deal with stress.

Nearly 70 percent of school children don't get enough sleep — less than 8 hours on school nights — according to the Centers for Disease Control and Prevention. This type of insufficient sleep has been linked to  depression , behavior problems and poor performance at school. However, most kids likely have access to a solution.

"Backlit tablets and computer screens do provide this type of light, but further research is needed to accurately measure how much light is produced by each product," Mariana Figueiro, the co-lead on the study, told TechNewsDaily. A bright screen setting is better than a dim setting, larger screens are better than small ones and closer to the face is better than farther away to achieve a stronger effect, she said. (That being the case, a lower-priced device such as a possible  iPad mini  might get a screen in front of more weary teens' eyes.)

The biology behind the study was based on what scientists call the cortisol awakening response, or CAR, in which the hormone cortisol spikes 30 to 60 minutes after waking. A high CAR has been associated with better preparedness for stressful and challenging activities.

During the study, 18 adolescents ages 12 to 17 years went to sleep in the Center's lab at 1:30 a.m. and were awakened at 6 a.m. The test was conducted one night a week over about three weeks. Some  kids  were exposed to short-wavelength blue light, while others remained in dim light for 80 minutes after wakening. They all wore a wristband that measured their activity levels and light exposure. Saliva samples were taken every 20 minutes to measure cortisol levels.

Blue light significantly increased cortisol levels compared with dim light exposure. The study found no difference in levels between girls and boys (evenly represented in the study), based on age or even between those who classified themselves as either night owls or early birds.

The takeaway for parents — short of getting kids to bed earlier — is to consider encouraging their teens to log some screen time within an hour of their alarm clocks going off. It could make for a more productive and less stressful day.

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