The first field study on the impact of light on teenagers’ sleeping habits finds that insufficient daily morning light exposure contributes to teenagers not getting enough sleep.
Disrupting Biological Rhythms
“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,” reports Mariana Figueiro, Ph.D., assistant professor and program director at Rensselaer Polytechnic Institute’s Lighting Research Center (LRC) and lead researcher on the new study.
“These morning-light-deprived teenagers are going to bed later, getting less sleep and possibly under-performing on standardized tests. We are starting to call this the teenage night owl syndrome.”
In the study just published in Neuroendocrinology Letters, Figueiro and LRC Director Mark Rea found that eleven 8th 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 5-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 nighttime,” explains Figueiro. “Our study shows melatonin onset was delayed by about 6 minutes each day the teens were restricted from blue light. Sleep onset typically occurs about 2 hours after melatonin onset."
The problem is that today’s middle and high schools have rigid schedules requiring teenagers to be in school very early in the morning. In addition, the schools are not likely providing adequate electric light or daylight to stimulate this biological or circadian system, which regulates body temperature, alertness, appetite, hormones and sleep patterns.