Does one hour of bright or short-wavelength filtered tablet screenlight have a meaningful effect on adolescents %26apos; pre-bedtime alertness, sleep, and daytime functioning?

作者：Heath Melanie; Sutherland Cate; Bartel Kate; Gradisar Michael^*; Williamson Paul; Lovato Nicole; Micic Gorica

来源：Chronobiology International, 2014, 31(4): 496-505.

DOI：10.3109/07420528.2013.872121

• Adolescents
• alertness
• chronotype
• light
• REM sleep
• sleep
• technology

Electronic media use is prevalent among adolescent populations, as is the frequency of sleeplessness. One mechanism proposed for technology affecting adolescents%26apos; sleep is the alerting effects from bright screens. Two explanations are provided. First, screens emit significant amounts of short-wavelength light (i.e. blue), which produces acute alertness and alters sleep timing. Second, later chronotypes are hypothesised to be hypersensitive to evening light. This study analysed the pre-sleep alertness (GO/NOGO task speed, accuracy; subjective sleepiness), sleep (sleep diary, polysomnography), and morning functioning of 16 healthy adolescents (M=17.4 +/- 1.9yrs, 56% f) who used a bright tablet screen (80 lux), dim screen (1 lux) and a filtered short-wavelength screen (f.lux; 50 lux) for 1 hr before their usual bedtime in a within-subjects protocol. Chronotype was analysed as a continuous between-subjects factor; however, no significant interactions occurred. Significant effects occurred between bright and dim screens for GO/NOGO speed and accuracy. However, the magnitude of these differences was small (e. g. GO/NOGO speed=23 ms, accuracy 13%), suggesting minimal clinical significance. No significant effects were found for sleep onset latency, slow-rolling eye movements, or the number of SWS and REM minutes in the first two sleep cycles. Future independent studies are needed to test short (1 hr) vs longer (%26gt;2 hrs) screen usage to provide evidence for safe-to-harmful levels of screenlight exposure before adolescents%26apos; usual bedtime.

• 出版日期2014