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OPTIMIZE YOUR HEALTH
Lower Your Risk for Dementia
Exercise Saves Brain Cells
By Sue Kim-Saechao, RN, MSN, CRNP, and Jannet Huang,
MD, FRCPC, FACE, ABHM
According to researchers, the brain loses an average of 15% to
25% of its tissue between the ages of 30 and 90, and most of these
losses are in the areas associated with memory, learning, and other
thinking-related processes.
A study published in the Journal
of Gerontology: Medical Sciences, found
the areas of the brain most affected by aging differed significantly
according to the fitness levels of the men and women studied.
In
the study, researchers used magnetic resonance imaging (MRI) to
analyze three-dimensional brain scans of 55 well educated adults
aged 55 to 79 who ranged in fitness from sedentary to competition-ready
athletes. In comparing the brain scans of the physically fit with
those of sedentary adults, they found the most distinct differences
were in these two types of brain tissue—those associated
with memory and learning. It wasn't that fitter people had better
brain densities; it was that exercise decreased the amount of brain-tissue
loss associated with aging.
Here are some ways by which regular exercise saves your brain:
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Improving concentration and attention: Brain imaging
studies show that physically-fit older adults have faster reaction
times—an indication of better concentration—than
their less-fit counterparts.
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Reducing gray matter loss: Physically
fit people show less of a decrease in gray matter in the
cortex than is normally seen with aging, which may suggest
a protective effect of exercise against nerve cell death.
This effect is most pronounced in areas of the brain involved
in executive cognition that typically decline most with aging.
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Promoting neurogenesis: Neurogenesis is the production
of new nerve cells as a result of neuronal cell division. Laboratory
animals that are allowed to voluntarily run on an exercise
wheel show increases in the generation and survival of new
neurons in the hippocampus (the area of the brain involved
in short term memory). This increased neurogenesis is associated
with improved learning.
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Strengthening synapses: In animals, running also
increases the strength of synaptic connections. This occurs
through the same molecular mechanism that is believed to underlie
long-term memory formation.
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Increasing growth factors: Nerve growth factors
(neurotrophins) play vital roles in nourishing and supporting
nerve cells. A growth factor called BDNF (brain-derived neurotrophic
factor) increases significantly in the brains of animals that
run voluntarily. Studies have shown that when people with depression
exercise in addition to taking antidepressants, their BDNF
levels go up and their depression symptoms decrease.
- Enhancing blood
flow: Exercise
also increases the density and size of brain capillaries, which
has the effect of increasing blood flow and oxygen to the brain.
This may in turn help support the survival of new neurons and
facilitate faster "firing" by
neurons.
Sources:
Disclaimer: The
information provided here is for “advice
only”, and not meant to provide specific medical recommendations
or replace the medical advice of your health care practitioner.
—July 2007
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Wellness e-Letter
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