[tabi] exercise may protect against vision loss
- From: "Chip and Allie Orange" <acorange@xxxxxxxxxxx>
- To: <tabi@xxxxxxxxxxxxx>
- Date: Thu, 5 Jun 2014 12:31:42 -0400
Below is an article I received in a health-related news letter:
http://www.bottomlinepublications.com/content/article/diet-a-exercise/aerobi
c-exercise-protects-eyes-from-macular-degeneration-and-other-retina-problems
Aerobic Exercise Protects Eyes from Macular Degeneration and Other Retina
Problems
Even for people with healthy eyes, protecting eyesight should be a primary
concern. That's because as we age, we are increasingly vulnerable to
degenerative eye diseases such as age-related macular degeneration (AMD).
These
diseases can strike anyone...are very tough to treat...and can lead to
severely
impaired vision, or even blindness, sometimes with horrifying speed.
Good news: A recent study suggests a simple (and even enjoyable) way to help
protect against AMD and other retinal problems. It's something that your eye
doctor probably won't think to mention...but it might do your eyes a world
of
good by directly benefiting your retinas.
This new study used healthy mice. Some of the mice were given treadmills and
trained to exercise for one hour, five days each week, at a moderate pace.
For
comparison's sake, other mice had identical living conditions-except that
their
treadmills did not move, so they were mostly inactive. After two weeks, the
mice
were intentionally exposed to a bright light for four hours. The light
exposure
was intended to damage the light-sensing photoreceptors of the retina in a
way
that's similar to the retinal neuron degeneration that occurs in humans who
have
AMD or a less common condition called retinitis pigmentosa.
Next, the mice were put back on the same exercise program (or lack thereof)
for
two more weeks. Halfway through and at the end of that time period, the
researchers did some tests. What they discovered...
After being exposed to the damaging bright light, the mice that had
exercised
showed two times greater retinal function, based on measurements of
electrical
activity of the retina, compared with the inactive mice.
Examination of the retinas showed that, even though numerous photoreceptors
had
indeed been damaged by the bright light exposure, the mice that exercised
had
more than twice as many healthy photoreceptors as the inactive mice.
The fact that the test results remained consistent two weeks after the
exposure
to the damaging light suggests that exercise's beneficial effects have some
power to persist...and may help slow the progression of vision-destroying
degenerative retinal diseases.
EXERCISE'S EYE BENEFITS EXPLAINED
What could account for such dramatic vision benefits from exercise? Part of
the
answer may come from another portion of the experiment that involved
measuring
the levels of brain-derived neurotrophic factor (BDNF), a protein involved
in
nerve growth. In a different set of mice, some exercised for nine days and
the
others did not. Then researchers tested BDNF levels in the retinas, brains
and
blood of the mice-and found that, in all three areas, the active mice had
significantly higher levels of BDNF than the inactive mice.
There's no known cure for AMD...and the treatments that can help slow its
progress are anxiety-provoking and uncomfortable, involving injections of
drugs
directly into the eyes. Compared to that, aerobic exercise seems like a
pleasurable walk in the park-quite literally!
Get motivated, get moving: This study makes a strong case that aerobic
exercise
directly benefits the retina and plays a significant role in protecting
photoreceptors. Of course, an animal study can't prove that what's good for
mouse eyes also is good for human eyes, particularly after just two weeks of
regular aerobic exercise...but it certainly could be true. Besides, we do
know
beyond a shadow of a doubt that aerobic exercise is highly beneficial to
people's bodies and brains. If you care about protecting your eyesight (and
who
doesn't?), let this study serve as yet one more excellent reason to add some
aerobic exercise to your day-to-day routine (with your primary-care
physician's
OK)-whether or not your eye doctor thinks to recommend it.
Sources: Machelle T. Pardue, PhD, associate professor, and Jeffrey H.
Boatright,
PhD, professor, department of ophthalmology, Emory University School of
Medicine, and the Atlanta VA Center for Visual and Neurocognitive
Rehabilitation, both in Atlanta. Their study was published in The Journal of
Neuroscience.
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