Does Exercise Change Your Brain?
September 18, 2015
Story at-a-glance
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Brain scans of a world-record holding athlete, who started
exercise in her late 70s and continued into her 90s, reveals
clues about the effects of late-life exercise
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The white matter of her brain, which connects neurons and
transmits messages in the brain, had fewer abnormalities
than that of her less-active peers
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Her brain’s memory center, or hippocampus, was also larger
and she outperformed typical adults aged 90 to 95 years on
tests of speed and memory
By Dr. Mercola
Olga Kotelko held more than 30 track-and-field world records in
her age category, which is particularly noteworthy because she began
athletic training at the age of 77 and continued into her 90s.
Ms. Kotelko passed away in 2014 at the age of 95, but not before
she allowed researchers to scan her brain for clues about the
effects of late-life
exercise. Notably, the white matter of her brain, which connects
neurons and transmits messages in the brain, had fewer abnormalities
than that of her less-active peers.
Her brain’s memory center, or hippocampus, was also larger and
she outperformed typical adults aged 90 to 95 years on tests of
speed and memory.1
Although the researchers didn’t have a scan of Ms. Kotelko’s
brain before she started exercising, they couldn’t say for
sure whether exercise was responsible for her notable brain
differences – but it did appear as though her brain was younger than
her age.2
Staying Physically Active As You Age May Boost Cognitive Function
The same researchers who conducted the above-mentioned study
carried out additional research on older adults ages 60 to 80. They
measured brain activity, physical activity, and aerobic capacity.
Those who were the most physically active had better brain
oxygenation and better patterns of brain activity, particularly in
the hippocampus and in connecting different brain regions together.
Such patterns are associated with improved cognitive function.3
What is perhaps most intriguing about the findings is they
occurred among older adults who were physically active but not
athletes. The study participants did not exercise formally but
rather got their activity in via walking, gardening, and simply
moving about each day – and those who moved the most had significant
brain advantages compared to their more sedentary peers.
Yet another study published regarding brain health and exercise
in older adults (ages 70 to 89) found no significant differences
among those who exercised for two years or attended health classes.4
However, their cognitive performance remained steady and did not
decline, which means exercise may have had a beneficial effect after
all (and so may have the stimulating effects of attending a health
class).
Exercise May Lower Your Risk of Dementia
Your brain is capable of rejuvenating and regenerating itself
throughout your life. It was once believed that once neurons die,
there’s nothing you can do about it. Hence deterioration and
progressive memory decline was considered a more or less inevitable
part of aging. Fortunately, that’s simply not true, especially if
you exercise.
According to John J. Ratey, a psychiatrist who wrote the book
Spark: The Revolutionary New Science of Exercise and the Brain,
there’s overwhelming evidence that exercise produces large cognitive
gains and helps fight dementia.
Research shows that those who exercise have a greater volume of
gray matter in the hippocampal region of their brains. According to
the authors:5
“After controlling for age, gender, and total brain
volume, total minutes of weekly exercise correlated
significantly with volume of the right hippocampus. Findings
highlight the relationship between regular physical exercise and
brain structure during early to middle adulthood.”
During exercise nerve cells release proteins known as
neurotrophic factors. One in particular, called brain-derived
neurotrophic factor (BDNF), triggers numerous other chemicals that
promote neural health and directly benefits cognitive functions,
including learning.
A 2010 study on primates published in Neuroscience also
revealed that regular exercise not only improved blood flow to the
brain but also helped the monkeys learn new tasks twice as quickly
as non-exercising monkeys.6
This is a benefit the researchers believe would hold true for
people as well. In a separate one year-long study, individuals who
engaged in exercise were actually growing and
expanding the brain's memory center one to two percent per year,
where typically that center would have continued to decline in size.
‘One of the Most Promising Non-Pharmaceutical Treatments to Improve
Brain Health’
Exercise initially stimulates the production of a protein called
FNDC5, which in turn triggers the production of BDNF. As mentioned,
in your brain BDNF not only preserves existing brain cells,7
it also activates brain stem cells to convert into new neurons, and
effectively makes your brain grow larger.
Research confirming this includes a study by Kirk Erickson, PhD,
in which seniors aged 60 to 80 who walked 30 to 45 minutes, three
days per week for one year, increased the volume of their
hippocampus by two percent.8
Erickson told WebMD:9
"Generally in this age range, people are losing one to
three percent per year of hippocampal volume. The changes in the
size of the hippocampus were correlated with changes in the
blood levels of the brain-derived neurotrophic factor (BDNF)."
Erickson also found that higher fitness levels were associated
with a larger prefrontal cortex. He called exercise "one of the
most promising non-pharmaceutical treatments to improve brain
health."
Similarly, a team at the University of Edinburgh followed more than
600 people, starting at age 70, who kept detailed logs of their
daily physical, mental, and social habits.
Three years later, their brains were imaged for age-related
changes, such as brain shrinkage and damage to the white matter,
which is considered the "wiring" of your brain's communication
system.
Not surprisingly, seniors who engaged in the most physical
exercise showed the least amount of brain shrinkage.10
Two additional mechanisms by which exercise protects and boosts your
brain health include the following:
- Reducing plaque formation: By altering the
way damaging proteins reside inside your brain, exercise may
help slow the development of Alzheimer's disease. In one animal
study, significantly fewer damaging plaques and fewer bits of
beta-amyloid peptides, associated with Alzheimer's, were found
in mice that exercised.11
- Decreasing BMP and boosting Noggin:
Bone-morphogenetic protein (BMP) slows down the creation of new
neurons, thereby reducing neurogenesis. If you have high levels
of BMP, your brain grows slower and less nimble.
Exercise reduces the impact of BMP so your adult stem cells can
continue performing their vital functions of keeping your brain
agile. In animal research, mice with access to running wheels
reduced the BMP in their brains by half in just one week.12,13
In addition, they also had a notable increase in another brain
protein called Noggin, which acts as a BMP antagonist. So exercise
not only reduces the detrimental effects of BMP, it simultaneously
boosts the more beneficial Noggin as well. This complex interplay
between BMP and Noggin appears to be yet another powerful factor
that helps ensure the proliferation and youthfulness of your
neurons.
Exercise Benefits Your Brain Health at Any Age
Although much research is focused on how exercise may benefit an
aging brain, exercise offers brain health benefits at
virtually any age, and this includes children. A review of 14
studies demonstrated that the more physically active schoolchildren
are, the better they do academically.14
According to the authors:
“There is… a growing body of literature suggesting that
physical activity has beneficial effects on several mental
health outcomes, including health-related quality of life and
better mood states.
In addition... there is a strong belief that regular
participation in physical activity is linked to enhancement of
brain function and cognition, thereby positively influencing
academic performance. There are several hypothesized mechanisms
for why exercise is beneficial for cognition, including:
(1) Increased blood and oxygen flow to the brain
(2) Increased levels of norepinephrine and endorphins
resulting in a reduction of stress and an improvement of
mood
(3) Increased growth factors that help to create new
nerve cells and support synaptic plasticity”
The increased blood flow that results from exercise also benefits
your brain, allowing it to almost immediately function better. As a
result, you tend to feel more focused after a workout, which can
improve your productivity at work and at home. Not to mention,
exercise has undeniable effects on your mood, with anxiety reduction
key among them. A study by Princeton University researchers revealed
that exercising creates new, excitable neurons along with new
neurons designed to release the GABA neurotransmitter, which
inhibits excessive neuronal firing, helping to induce a natural
state of calm.15
Commonly prescribed anti-anxiety drugs like Ativan, Xanax, and
Valium actually exert a calming effect in this same manner, by
boosting the action of GABA. The mood-boosting benefits of exercise
occur both immediately after a workout and continue on in the long
term.
In addition to the creation of new neurons, including those that
release the calming neurotransmitter GABA, exercise boosts levels of
potent brain chemicals like serotonin, dopamine, and norepinephrine,
which may help buffer some of the effects of stress. Exercise is
also one of the most effective prevention and treatment strategies
for
depression.
Even Exercise You Did in Your 20s May Boost Your Brain Function in
Middle Age
If there were still any question whether exercise can change your
brain for the better, consider a study by researchers at the
University of Minnesota. They examined data collected over a 25-year
period from 2,700 US adults, concluding that those who had greater
cardiorespiratory fitness in their teens and 20s scored better on
cognitive tests in their mid-40s and 50s.16
For each additional minute spent on the treadmill during the
initial test, he or she was able to accurately recall 0.12 more
words at follow-up 25 years later. Those who were fitter in their
early adulthood also scored better on tests designed to assess
reaction speed and the mental agility needed to answer trick
questions.
The impact of fitness was deemed to be independent of other
dementia-related risk factors such as
diabetes, high cholesterol, and
smoking. The good news is that if you were fit in your 20s, it’s
likely to have lasting benefits. But if you weren’t, you may feel
slightly defeated… don’t. Among those who weren’t the most
fit in their 20s, but who improved their fitness level in the
decades that followed, their scores on the cognitive tests were
higher than those whose fitness levels remained the same or got
worse. So it’s truly never too late to start exercising. Even if
you’ve never exercised a minute in your life, you can start today
and immediately begin to experience the benefits.
Remember, those who exercise the most tend to have the least
amount of
brain shrinkage over time. Not only that, but exercise actually
causes your brain to grow in size. So get moving and
keep moving for best results. To get the most out of your
workouts, I recommend a comprehensive program that includes
high-intensity interval exercise, strength training (especially
super slow workouts), stretching, and core work, along with
walking about 10,000 steps a day.
© Copyright 1997-2015 Dr. Joseph Mercola. All Rights Reserved.
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