For this study researchers first monitored the sleep of 19 healthy study subjects aged 20-29 for one week using a special device that accurately detects when individuals fall asleep and wake up. Study subjects also kept a sleep diary and recorded information about the quality of their sleep.
For the second part of the study, the participants were brought into the sleep lab. From 9 pm to 11 pm (the normal period of melatonin release) they were exposed to computer screens that emitted either blue or red wavelengths of light. There were notable differences in sleep quality and duration relative to the blue versus red light exposures. After the blue light, the study subject’s sleep duration diminished by about 16 minutes. Melatonin release was also significantly reduced. Most striking, however, was the increase in sleep disruption after exposure to the blue light. After the blue light exposure, study subjects experienced 6.7 to 7.6 unnoticed awakenings during the night. This contrasted with 4.5 after the red light. Not surprisingly, the study subjects felt more tired and were in a worse mood over the course of the day after exposure to the blue light.
Forty percent of Americans report unrestful or inadequate sleep. My hunch is that technology is playing a much bigger role in our epidemic of poor sleep than is recognized. Fortunately, filters are now readily available for most devices that screen out the blue light. Use them!
Join me this Friday, September 29th, for an awesome web-class: