Neuroscientists around the globe agree that physical activity is the best medicine to maintain brain health throughout your lifespan. Why is physical activity so good for your brain?
There
are many reasons that exercise is good for your brain. These include:
increased blood flow, which improves cerebrovascular health; the release
of neurotrophic factors like BDNF, which stimulates the growth of new
neurons; and the benefits of glucose and lipid metabolism which bring
nourishment to the brain.
Recently, researchers at the
Beckman Institute at the University of Illinois at Urbana-Champaign
found that physical activity is also associated with improved white
matter integrity. In two separate studies—released within the past
month—researchers found that physical activity improved the white matter
integrity of physically fit children aged 9 to 10 and also in “low fit”
participants aged 60 to 78.
The researchers found that physical activity improves the
microstructures of white matter in the brain. White matter integrity is
linked to faster neural conduction between brain regions and superior cognitive performance.
Multiple
Sclerosis (MS) directly affects the integrity of white matter. In MS
lesions the myelin sheath around the axons gradually deteriorates.
Changes in white matter, known as amyloid plaques, are associated with Alzheimer's disease and other neurodegenerative diseases.
What is the White Matter of Your Brain?
White matter consists mostly of glial cells and myelinated
axons that act as communication lines between various regions of gray
matter in the cerebrum. White matter also allows communication between the cerebrum and lower brain centers including the cerebellum.
When
white matter tissue is freshly cut in a living brain, it actually
appears pinkish because myelin is composed largely of lipid tissue that
is veined with capillaries for vascularization. According to Arthur Kramer,
the director of the Beckman Institute, one reason that exercise might
improve white matter integrity is that physical activity gets the blood
pumping through the brain and improves vascularization of these
capillaries. There is also the possiblilty that physical activity
improves myelination.
White matter carries nerve signals
between the gray matter in one brain region to another brain region.
The more streamlined and compact your white matter is, the faster and
more efficiently your brain functions.
These new studies
show that physical activity appears to make the axons in white matter
more tightly bundled and compact. Exercise appears to improve white
matter integrity which is correlated with more efficient communication
between brain regions from childhood into our golden years.
Aerobic Fitness in Children Linked to White Matter Integrity
The first new study from
the Beckman Institute, “Aerobic Fitness is Associated with Greater
White Matter Integrity in Children,” was published August 2014 in in the
open-access journal Frontiers in Human Neuroscience. In this
study U. of I. kinesiology and community heatlh professor Charles
Hillman, postdoctoral researcher Laura Chaddock-Heyman and their
colleagues found that physically fit children had more fibrous and
compact white matter tracts in the brain than their less fit peers.
In
a press release, University of Illinois researcher Laura
Chaddock-Heyman said, "Previous studies suggest that children with
higher levels of aerobic fitness show greater brain volumes in gray
matter brain regions important for memory and learning. Now for the first time we explored how aerobic fitness relates to white matter in children's brains."
Chaddock
and her colleagues used a technique called diffusion tensor imaging
(DTI) to look at five white matter tracts that play a role in attention
and memory. The findings revealed significant fitness-related
improvements in the integrity of several white matter tracts.
For
this study, the researchers didn't specifically test for cognitive
differences in the children. A wide range of studies over the past
decades have found a link between aerobic fitness levels, improved
cognitive function, and higher academic test scores. "Previous studies
in our lab have reported a relationship between fitness and white matter
integrity in older adults," Kramer said. "Therefore, it appears that
fitness may have beneficial effects on white matter throughout the
lifespan."
Avoiding a Sedentary Lifestyle Benefits White Matter Integrity As You Age
The second new study from
the Beckman Institute, “Physical Activity and Cardiorespiratory Fitness
Are Beneficial for White Matter in Low-Fit Older Adults” was published
September 2014 in the journal PLOS ONE. Postdoctoral researcher
Agnieszka Burzynska conducted the research with Art Kramer and
kinesiology and community health professor Edward McAuley.
In
this study, the researchers found a strong link between the structural
integrity of white matter tracts and an older person's level of daily
activity. Interestingly, it wasn't the extent to which the person
engaged in moderate or vigorous exercise, but simply if someone spent
most of the day being sedentary. Avoiding a sedentary lifestyle can have
dramatic effects on your brain health by maintaining the integrity of
your white matter throughout a lifespan.
Hippocrates was
right when he said, “Walking is man’s best medicine.” Art Kramer has
spent decades researching the brain benefits of physical activity. In a
recent conversation, Kramer said that the best news about the latest
findings is that you don’t have to be running marathons or winning
triathlons to reap the brain benefits of physical activity. I agree.
In
our conversation, Art Kramer and I spoke about the difficulty of
motivating people to break a sweat. He emphasized that the most exciting
aspect of this new study is that it shows that the real enemy is
sedentarism. This study indicates that just a little bit of movement
every day helps preserve the integrity of your brain’s white matter.
Conclusion: Physical Activity Improves Brain Health and Cognitive Function at Any Age
These
results come at a critical time. In a digital age, our society has
become increasingly unfit and sedentary. As the father of a 6-year-old, I
am passionate about public health and education policies that affect children's brain health and overall development.
As
adults we can make daily lifestyle choices that include physical
activity. Unfortunately, most children are subject to policies that tend
to reduce or eliminate opportunities for physical activity during the
school day.
Reducing the time and availability for
children to be physically active during the school day could have
negative impacts on the integrity of white matter tracts, which might
reduce brain efficiency and could lead to lower test scores.
One
of the most interesting findings from recent research is that white
matter microstructure in the corona radiata is linked to mathematics
performance (van Eimeren et al., 2008).
Ironically, in an attempt to prepare children for the Common Core
Standards and No Child Left Behind testing by forcing them to sit still
in a chair we may actually be sabotaging a child's brain from optimizing
white matter integrity.
Laura Chaddock-Heyman and co-authors sum
up the importance of physical activity in the conclusion of their study
when they say, “In fact, our study raises the possibility that greater
white matter integrity, perhaps via greater myelination, is one pathway
by which higher fit children excel in cognitive and academic performance
compared to their less fit peers. Hopefully these findings will
reinforce the importance of aerobic fitness during development and lead
to additional physical activity opportunities in and out of the school environment.”
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