The Brain On ExerciseBy Charles Sorrese

Why Exercise? While it may be popular

today to exercise for looks, there may be more important reasons for lacing up our gym shoes.

Studies indicate that the effects of exercise can greatly improve and change the way our brains function. This can be useful for common health problems that we face today.

But first, it may be good to look at how exercise and the brain have a long history.

Exercise and our Ancestors

To survive, our hunter gatherer ancestors had to be on the move all the time and learn to find and store food. They exercised all the time.

The relationship between finding food, physical activity, and learning is hardwired into the brain’s circuitry. (Ratey, 2008, p. 3).

Today, 74% of adults in the United States do not meet the recommendation of at least 30 minutes of moderate-intensity physical activity on most days of the week. (Hillman, 2008, p. 58).

Why is this a problem?

Stress By definition, stress is a threat to the body’s equilibrium.

On one end of the spectrum is normal every day acute stress. It is a state of mild alertness. This type of stress isn’t a problem because it comes and then it goes. (Ratey, 2008, p.61)

On the other end of the spectrum is chronic stress. This kind can lead to full blown mental disorders such as anxiety, depression, high blood pressure, and heart problems. It can even tear at the architecture of the brain. (Ratey, 2008, p. 63)

Stress continued..

In the brain, when neurons fire, it is a form of stress. Learning something new, or moving our muscles are creating stress in the brain, to a small degree.

The emotional feeling of stress is actually the product of the underlying stress of the neurons firing in our heads.

To the brain, all stress is the same, but the difference comes down to how much stress there is. (Ratey, 2008)

http://www.youtube.com/watch?v=OHl7BewJ0yU (What too much stress can do to the brain)

Stress continued… Fortunately, we typically have a

measure of control over stress. We can choose how we respond to it.

However, the problem with chronic stress is that it keeps the brain locked in the same patterns for an extended period of time that can be difficult to break out of.

Reacting passively to this can actually damage the neurons. This is where active steps to take control can be necessary. (Ratey, 2008, p. 65)

This is where exercise can come in handy.

Stress continued...

When we exercise, neurons get broken down and built up again just like muscles.

Stressing the neurons during exercise actually makes them stronger to face future challenges.

In this sense, exercise makes the neurons more able to deal with stress, the same way it makes muscles able to handle heavier loads of weight. (Ratey, 2008, p. 69)

Exercise also wards off stress that comes as a result of the fight or flight response.

Stress continued… The purpose of the fight or flight response to stress is to mobilize us to act. If we were to be attacked by a bear, we would naturally feel a need to run or fight.

Fortunately, we don’t always have to face bears today. But the instinct is still there, and can be activated during other stressful situations.

Physical activity is a natural response to fight or flight, and can prevent the negative consequences of stress, which is why exercise makes sense.(Ratey, 2008, p. 70)

When we mobilize (exercise) in response to stress, we’re doing what humans evolved to do over the past several million years.

Stress continued…

During fight or flight, the Hypothalamus releases Norepinephrine, which arouses attention, and Dopamine, which sharpens and focuses it. (Ratey, 2008, p. 72)

A detailed animation can be seen here: http://www.youtube.com/watch?v=V08dWz5XNBA&feature=related

This is great if we are getting ready to run or fight. But if one brain structure (fight or flight) is active, it must come at the expense of another.

As the fight or flight response is going, the thinking (executive) parts of our brain are being robbed of energy.

This can explain why it is difficult to think under stress. (Ratey, 2008, p. 70)

Learning

Exercise is also connected to learning. But what does learning have to do with exercise?

If we still have the biology of our ancestors, it would make sense that our ability to learn is still tied in with physical activity.

If it helped our ancestors learn to find and store food, can exercise make our brain learn better today?

Learning continued…

To see what exercise can do to the brains of mice, scientists divided rats into four groups.

The first three groups were mice that ran for two, four, or seven nights.

The final group was a control that had no running wheel, and did not exercise.

Scientists found out that the mice that exercised grew new neurons. The further they ran, the more neurons they grew. They were also able to learn faster and navigate mazes more quickly. (Ratey, 2008, p. 44)

Learning continued…

Neural growth in mice brains happen in the Hippocampus. (Ratey, 2008, p. 43)

Aerobic activity improves learning and promotes the development of new neuronal architecture.” (Hillman, 2008, p. 63)

BDNF (brain derived neurotophic factor) is known as “miracle grow” for neurons.

Physical exercise increases hippocampal brain-derived neurotrophic factor (BDNF). (Chen, 2007, p. 118)

An increase in cell proliferation in the hippocampus is one of the most consistently observed effects of exercise treatment”(Hillman, 2008, p. 62)

BDNF

Learning continued…

Students in Naperville, IL that go for a run before class are more prepared to learn. Their senses are heightened, their focus and mood are improved. (Ratey, 2008, p. 35)

According to this study, the students who ran before their classes did better on tests than their peers who did not run.

Exercise has been demonstrated to enhance the secretion of a number of important neurotransmitters. (Chenn, 2007, p. 118)

Going for a run is like taking a little bit of Prozac and Ritalin at the same time because it elevates and balances the brain’s neurotransmitters to increase focus and mood. (Ratey, 2008, p.38)

Learning continued…

These neurotransmitters consist of Dopamine and Serotonin, which in combination, calm the mind and increase good feelings.

(Ratey, 2008, p. 38)

This can explain why the students have an easier time paying attention in class after a run.

They feel calm and happy, from the effects of exercise, or more so, from dopamine and serotonin.

According to Chen (2007), “antidepressant induced increases in BDNF expression”(p. 118)

This is an indicator why exercise can also act as an anti- depressant.

Conclusions 30 minutes a day of moderate-

intense aerobics has shown improvement in attention, as well as improving ability to learn through the growth of new neurons in the Hippocampus. (Hillman, 2008, p. 58)

The new neurons that come from exercise are designed for learning. If we grow them, but don’t fill them with knowledge, then the learning aspect won’t count as much. (Ratey, 2008, p. 51)

Nevertheless, lacing up our gym shoes is a good way to fight stress the way our ancestors did a millions of years ago.

Annotated Bibliography

John J. Ratey (2008). SPARK: The Revolutionary New Science Of Exercise And The Brain. New York: Little, Brown and Company

This book describes studies done on rodents and humans during and after exercise. The results suggest solid evidence for exercise changing the brain and improving learning abilities, as well as dealing with stress.

Chen, M., & Russo-Neustadt, A. (2007). Running exercise- and antidepressant-induced increases in growth and survival-associated signaling molecules are IGF-dependent. Growth Factors, 25(2), 118-131. doi:10.1080/08977190701602329.

This article suggests that regular aerobic exercise increases the brains ability to grow new neurons. It states evidence that BDNF increases in the Hippocampus during aerobic exercise which sparks the growth of new neurons. It also states the similarities between exercise and anti-depressants.

Annotated continued…

Hillman, C., Erickson, K., & Kramer, A. (2008). Be smart, exercise your heart: exercise effects on brain and cognition. Nature Reviews Neuroscience, 9(1), 58-65. doi:10.1038/nrn2298.

This article suggests how much exercise is needed for us to have an enhanced sense of cognition. It recommends 30 minutes of aerobics at least 3 days a week at moderate- high intensity.