Sunday, May 15, 2011

Blue Light and the Circadian Clock

Researchers at the Rensselaer Polytechnic Institute's Lighting Research Center (LRC) in Troy, New York are proving that exposure to blue light is tied to the day/night sleep cycles of our circadian rhythms.

Mariana Figueiro, PhD., who heads the LRC’s light and health program explains:

“Within the mechanism that affects the circadian system are two color opponent channels. One of those is the blue vs. yellow (BY) channel, which seems to participate in converting light into neural signals to the part of the brain that generates and regulates circadian rhythms.”

A person attuned to the changing colors of outdoor light will notice that just after the orange-colored sun sets, the world is bathed in blue light from the twilight sky. So perhaps it’s not surprising that our body rhythms are tuned by this color.

In one LRC study, patients with Alzheimer’s disease experienced more hours of sleep per night after being exposed to blue LED lights than they did after being exposed to red lights.

“Blue sky is ideal for stimulating the circadian system because it’s the right color and intensity, and it’s ‘on’ at the correct time for the right duration—the entire day,” said LRC director Mark Rea, Ph.D.,

Presumably, since non-human animals also have the BY channel, they would respond to the same signals. 
Science Daily article about waking up teens with colored light
RPI Lighting Research Center article
Painting is called "Bonfire" by Isaac Levitan


eric said...

semi off topic, but last night while walking around my condo complex i noticed the flickering lights in all the windows of people watching tv.

i never really noticed it before but 80 to 90 percent of the light was blue.

when i got home that night i tried to see if the majority of color coming on the tv screen was blue, it didnt appear to be but from what i viewed outside from all the window lights 80 to 90 percent of the color coming across a tv screen is blue? not sure what to make of this?

phiq said...

@eric - maybe that's why people fall asleep in front of the TV a lot... ;-P

jbgibson said...

There are cool (and warm :) ) applications (f.lux, redshift) that tune your screen's light more blue or more red by time of day. They're intended to keep one from unintentionally telling your body's clock "day! day!" when you use a computer after dark.

Which makes me wonder if changing over to compact fluorescents instead of incandescent bulbs could be exacerbating many folks' insomnia...