The effects of different bedroom light environments in the evening on adolescents

Different indoor light environments can affect both the physiology and psychology of people, such as circadian rhythm, sleep quality, human performance, emotion and cognition. Recently, this topic has become an attractive and valuable subject for human health. Many studies focus on the light on sleep quality, whereas the research of whether the light environment in the evening affecting human performance the following day is limited. Besides, the previous works generally conduct on adults as their participants, however, little is known about how light impacts adolescents. In this study, we concern about the effects of different correlated color temperature (CCT) light environments in the bedroom on adolescents. We compared the sleep quality, next-morning sleepiness, and fatigue recovery of exposure to the traditional fluorescent lamp (high CCT, 6000 K) with a novel light-emitting diode (low CCT, 2000 K) light for 1 h before bedtime. Twelve male adolescents (age: 12.8 ± 1.7) were randomly allocated in two different CCT light environment groups to complete a 10-day light intervention. The results of the Pittsburgh Sleep Quality Index (PSQI), serum melatonin and proteinuria indicated that the subjects who were exposed to the low CCT light directly before sleeping had better sleep quality (p < 0.05), reduced next-morning sleepiness (p < 0.05), and slightly decreased fatigue, compared to those in the high CCT light group. These findings illustrate that exposure to the low CCT light environment before bedtime is probably more appropriate than the high CCT light environment for adolescents.