Does Exercise Change Your Brain?

Exercise Affects Brain Health

Story at-a-glance -

  • 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
  • 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

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.

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