TROY, N.Y., July 27 (UPI) — Long daylight hours in spring influence the sleeping patterns of teens, researchers at Rensselaer Polytechnic Institute in Troy, N.Y., said.
“Biologically, this increased exposure to early evening light in the spring delays the onset of nocturnal melatonin, a hormone that indicates to the body when it’s nighttime,” Mariana Figueiro of the RPI Lighting Research Center says in a statement. “This extended exposure adds to the difficulties teens have falling asleep at a reasonable hour.”
This, coupled with getting up early to go to school, may lead to teen sleep deprivation and mood changes, an increase risk in obesity and perhaps under-performance in school, Figueiro says.
The study of 16 eighth-grade students in upstate New York experienced a delay in melatonin onset by an average of 20 minutes measured in one day in spring relative to one day in winter. Daylight is rich in short-wavelength — blue — light, which maximally stimulates the biological clock.
“As a general rule, teenagers should increase morning daylight exposure year round and decrease evening daylight exposure in the spring to help ensure they will get sufficient sleep before going to school,” Figueiro says.
The findings are published in Chronobiology International.
Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.