Insufficient exposure to morning light may be instrumental in depriving teenagers of enough sleep, a new study says.
“As teenagers spend more time indoors, they miss out on essential morning light needed to stimulate the body’s 24-hour biological system, which regulates the sleep/wake cycle,” says Mariana Figueiro, assistant professor at Rensselaer Polytechnic Institute’s Lighting Research Centre (LRC), who led the study.
“These morning-light-deprived teenagers are going to bed later, getting less sleep and possibly under-performing on standardised tests. We are starting to call this the teenage night owl syndrome,” says Figueiro.
Figueiro and LRC director Mark Rea found that 11 eighth grade students who wore special glasses to prevent short-wavelength (blue) morning light from reaching their eyes experienced a 30-minute delay in sleep onset by the end of the five-day study.
“If you remove blue light in the morning, it delays the onset of melatonin, the hormone that indicates to the body when it’s night time,” explains Figueiro, according to an LRC release.
“Our study shows melatonin onset was delayed by about six minutes each day the teens were restricted from blue light. Sleep onset typically occurs about two hours after melatonin onset,” she says. The findings were published in Neuroendocrinology Letters.