Natural light’s ability to dictate sleep quality may cause disturbances during seasonal changes, according to a new US investigation on teenagers’ sleep.
The study, at Rennselaer Polytechnic Institute’s Lighting Research Centre in Troy, New York, compared the sleep patterns of teenagers during winter and spring test periods and found marked differences. In the springtime the participants were found to produce melatonin - the sleep-inducing hormone - on average twenty minutes later than in winter, which had the effect of making them fall asleep later and sleep less.
As well as delayed sleep onset and shorter sleep times, the light issue was linked to sleep deprivation side effects such as irritability, weight gain and poor academic performance.
Notably, the researchers found that exposure to natural light through seasonal changes was the most powerful light-related barrier to sleep, greater than artificial and electronic light in the home.
The results of the study support the theory that they body’s internal rhythm and sleep quality is largely dictated by lightness and darkness.
“This is a double-barrelled problem for teenagers and their parents. In addition to the exposure to more evening daylight, many teens also contend with not getting enough morning light to simulate the body’s biological system, which also delay’s teens’ bedtimes,” said researcher Mariana Figueiro, in the Seattle Times. “As a general rule, teenagers should try to increase their morning daylight exposure year-round and decrease evening daylight exposure in spring to help ensure they will get sufficient sleep before going to school.”
The study was published in the journal Chronobiology International.