How the study was conducted at Rensselaer (via Rensselaer Polytechnic Institute)
The daily life of many humans today involves looking at screen after screen throughout the day and night. At the same time, disorders like depression and insomnia are on the rise. In a study from 2010, researchers at Ohio State University found that dim lights at night cause dramatic changes to the hippocampus of mice, which leads to depression-like symptoms.
Now, researchers from the Lighting Research Center (LRC) at the Rensselaer Polytechnic Institute in New York, have found that prolonged exposure to backlit screens can have significant effects on levels of melatonin, a hormone which helps regulate sleep.
Brittany Wood, research specialist from the LRC, and her team, conducted a study where they asked 13 subjects to use backlit screens for extended periods of time. At some points, the subjects were told to wear orange-tinted goggles and goggles with embedded 470-nm blue LEDs. Both orange and blue light are already known to affect melatonin levels. All the participants also wore a device called a dimesimeter, which continuously records circadian (our natural 24 hr cycle) light and activity, to record personal light exposure.
The study’s results show that 60 minutes of exposure, to just the backlit screen, does not have a significant effect on melatonin. However, after 120 minutes, melatonin levels decreased by 22%. The team also found that the type of task being performed varies the photopic illuminance levels at a range of 5 lux to 50 lux, so task management, especially at night, is important. Until screen manufacturers can resolve this issue with their products, the LRC recommends turning off, or at least dimming the displays at night. They say “circadian-friendly” electronics could alleviate seasonal affective disorder and sleep disorders by decreasing and increasing melatonin levels at appropriate times during the day.
As we stare at our glowing rectangles endlessly, keep it in mind. Moderation still is the best policy. I'm one to talk, well over two hours of reading at night - on the phone.
This reminds me of how I watched the Olympics live this past summer, in the early morning....