Light deficiencies in the morning delay adolescents falling asleep and may contribute to sleep deprivation, according to a study reported in Neuroendocrinology Letters.
Researchers at the Rensselaer Polytechnic Institute’s Lighting Research Center (LRC) in Troy, New York, conducted a study on a group of 11 XNUMX-year-olds from Chapel Hill, North Carolina high school. In the morning they put on glasses that stopped the light with short wavelengths (ie blue).
After 5 days of experience, young people began to fall asleep half an hour later than at the beginning.
According to Dr. Mariana Figueiro, the lead researcher, eliminating blue light in the morning delays the release of melatonin, a hormone that tells the body when it’s night. We usually fall asleep 2 hours after we start producing this hormone. The latest research shows that on each day in which access to blue light was blocked in the early hours, melatonin began to release about 6 minutes later.
According to the researcher, the observations of her team suggest that the lack of daylight in the morning may disrupt biological rhythms. The problem is that rigid timetables in middle and high schools require young people to come to school early in the morning. These students often do not come into contact with the light in the morning because they arrive at school before or during sunrise, regrets Dr Figueiro.
This prevents them from receiving the right amount of light needed to tune their biological clock to the natural 24-hour cycle of light changes on Earth. The biological clock regulates all life processes and functions of our body – body temperature, activity, appetite, hormone secretion, sleep.
As a consequence, students fall asleep later and do not get enough sleep, and may therefore have lower academic performance. The term teen owl syndrome has even come into use recently, comments Dr Figueiro.
Additionally, schools are often not well lit to stimulate the biological clock in adolescents. Our biological clock reacts to light differently from our sense of sight. It is much more sensitive to blue light. Therefore, even seemingly good classroom lighting, which allows reading and learning, may not be enough to activate our clock – explains the specialist.
Dr Figueiro hopes that thanks to her team’s research, school authorities will start planning classroom lighting more consciously, increasing access to daylight, for example by using skylights in the ceiling.
This work is also important for people who work shifts (day / night) and for those with Alzheimer’s (the most severe type of dementia) who go to bed very irregularly. Studies have shown that the lack of synchronization between the daily day / night cycle and our activity and night rest increases the risk of heart disease, diabetes, seasonal depression and some cancers over time. Earlier research by Dr. Figueiro has shown that skilful light therapy can regulate sleep in Alzheimer’s patients. (PAP)