Night colour
| credits: File copy
| credits: File copy
When
it comes to some of the health hazards of light at night, a new study
suggests that the colour of the light can make a big difference.
In a study involving hamsters,
researchers found that blue light had the worst effects on mood-related
measures, followed closely by white light.
But hamsters exposed to red light at
night had significantly less evidence of depressive-like symptoms and
changes in the brain linked to depression, compared to those that
experienced blue or white light.
The only hamsters that fared better than those exposed to red light were those that had total darkness at night.
The findings may have important
implications for humans, particularly those whose work on night shifts
makes them susceptible to mood disorders, said Randy Nelson, co-author
of the study and professor of neuroscience and psychology at The Ohio
State University.
“Our findings suggest that if we could
use red light when appropriate for night-shift workers, it may not have
some of the negative effects on their health that white light does,”
Nelson said.
The study appears in the Aug. 7, 2013, issue of The Journal of Neuroscience.
The research examined the role of
specialized photosensitive cells in the retina — called ipRGCs — that
don’t have a major role in vision, but detect light and send messages to
a part of the brain that helps regulate the body’s circadian clock.
This is the body’s master clock that helps determine when people feel
sleepy and awake.
Other research suggests these
light-sensitive cells also send messages to parts of the brain that play
a role in mood and emotion.
“Light at night may result in parts of
the brain regulating mood receiving signals during times of the day when
they shouldn’t,” said co-author Tracy Bedrosian, a former graduate
student at Ohio State who is now a postdoctoral researcher at the Salk
Institute. “This may be why light at night seems to be linked to
depression in some people.”
Source: Science Daily.
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