From bad sleep to city-bound sea turtles,
we all know artificial lighting messes with our circadian world.
Now new research links
it to childhood obesity and even some forms of cancer.
 
Just to refresh: There's night and there's
day -- and life here on Earth evolved to roll
with varying degrees of light exposure. For
us diurnal humans, that meant ruling the sunlit
hours and hitting the hay in the evening.
But then came fire, lanterns, electricity
and now we're constantly lit by nightlights,
street lamps and countless glowing screens.
Hey, modernity is nice, but what's the cost?
New research out of Australia and Israel suggests
some troubling answers.
Researchers from the Queensland University
of Technology studied 3-5 year-olds from six
Brisbane childcare centers. Specifically,
they looked at each child's sleep, activity
and light exposure over a two-week period.
They also noted height, weight and body mass
index. Then they followed up with the children
a year later.
In a paper published in the journal PLOS One,
they found that slimmer children received
the most light exposure in the afternoon -- and
that's both indoor and outdoor lighting. Futhermore,
moderate light exposure EARLY in the day (and
greater exposure overall) correlated to increased
body mass index 12 months later.
It's not that surprising given what we already
know. Artificial light exposure can interfere
with circadian rhythm and alter the expression
of melatonin, impacting sleep as well as hormonal
functions.
Research from Israel's University of Haifa
seems to back this up. In a paper published
in the International Journal of Obesity, they
connect the dots from artificial lighting
at night (particularly white LED light) to
melatonin suppression and a metabolic tendency
for increased body mass. Furthermore, they
point to previous Israeli studies linking
light pollution to increased cases of breast
and prostate cancer -- potentially due to
melatonin's anti-oxidant and anti-cancer properties
that are lost in light-induced suppression.
There's still quite a lot of work to be done
here, but the science presents us daywalkers
with a troubling picture: With our lamps and
our tablets, we've transformed the darkness
-- and potentially opened a previously-unknown
doorway to disease.
So what about you? Are you planning to turn
off a lamp or two this evening? Tell us what
you think about the science here, and for
more weird wonders, be sure to check out now.howstuffworks.com
each and every day.
