The Effect of a Dynamic LED Light Intervention on Sleep Quality of Adolescent Students

Abstract: Objective: Previous studies have revealed positive effects on subjective alertness, performance and general sleep patterns, with exposure to light conditions adapted to time of day according to the circadian system. This study aimed to investigate the impact of a dynamic LED light intervention on sleep quality of adolescent students. Methodology: Twenty eight seventh-grade subjects were recruited for the intervention study divided into one control group and one intervention group. After ensured baseline comparability of the groups, the intervention group was exposed to a dynamic light regime (ranging from 2700 to 6500 K and 535 to 1050 lux), during two one-week periods. Jawbone activity trackers, Karolinska sleepiness scale (KSS) and sleep logs were used for objective and subjective assessments of sleep quality. Result: Statistically significant effects were observed between groups, during the second study week (Mon-Wed), implicating an increased sleep quality in terms of number of awakenings (p = 0.024, p = 0.064 and p = 0.087) and sleep efficiency (p = 0.050, p = 0.077 and p = 0.052). Self-reported sleepiness showed no significant difference between studied groups. Conclusion: The present study suggests that the dynamic light intervention leads to improved sleep quality in terms of less number of awakenings and increased sleep efficiency. Future research are required for validation of the result.