Dimly Lit Teens

Abstract

Video games and texting are not the only reasons teenagers don't go to bed when they should. Lack of exposure to outdoor light is messing with their bodily rhythms and keeping them from getting sleepy when they should, according to research from the Rensselaer Polytechnic Institute (RPI) in Troy, New York. A team led by Mariana Figueiro of RPI's Lighting Research Center conducted an experiment at a well-lit school in Chapel Hill, North Carolina, which has skylights that allow students maximal exposure to daylight. For 5 days, 11 eighth-graders wore orange glasses that blocked shortwavelength blue light, the kind that lab experiments have shown is important for setting the circadian clock. Researchers found that at the end of the week, the onset of sleep-inducing melatonin in the children was delayed by a half-hour. “The amount of light we get indoors is below threshold for activation of the circadian system,” says Figueiro, whose report appeared last week in Neuroendocrinology Letters . This contributes to the fact that “some kids can't fall asleep before 2 or 3 a.m.” ![Figure][1] CREDIT: PHOTOS.COM Brown University sleep expert Mary Carskadon says the experiment lacked controls. But she agrees with Figueiro that the shortage of outdoor light in most schools—compounded by the indoor-oriented existence of the modern teen—may be contributing substantially to below-par school performance. [1]: pending:yes