Rewire Your Brain: Think Your Way to a Better Life

mitochondria
, which are the energy factories of cells, turn the glucose 
into
adenosine triphosphate
(ATP), the principal type of fuel that a 
cell can burn. This conversion process produces free radicals, which 
I discussed in chapter 5 . Normally, the cell produces protective 
enzymes as internal antioxidants that mop up the waste products. 
Metabolic stress occurs when the cells can ’ t produce enough ATP. 
It ’ s as if they run out of gas. This happens because glucose can ’ t get 
into the cell or because there is not enough glucose. Finally,
excito-
toxic stress
(a condition destructive to neurons) occurs when there is 
not enough ATP to keep up with the increased energy demands of 
excessive glutamate activity. 
Fortunately, exercise promotes repair mechanisms that deal with 
the different types of stress. These repair mechanisms promote 
recovery and strengthen the entire body, including the brain. This 
stress - and - recovery process goes beyond strengthening to actually 
rebuilding on multiple levels. 
The names of the most powerful repair molecules look like a virtual 
alphabet soup, but what they do is profound. For example, exercise 
spurs into action the following brain - enhancing hormones: 
•
Insulin - like growth factor (IGF - 1)
•
Vascular endothelial growth factor (VEGF)
•
Fibroblast growth factor (FGF - 2)
IGF - 1 is a hormone released by the muscles when there is a 
need for fueling the cells during a physical activity. It increases 
the production of receptors for insulin. Since glucose is the major 
energy source in the brain, IGF - 1 works with insulin to deliver it to 
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the brain cells and manage glucose levels. It teams up with BDNF, 
which increases in the brain during exercise, and together they acti-
vate neurons to produce more serotonin and glutamate. Although 
chronic stress increases cortisol and lowers IGF - 1, exercise reverses 
that trend. 
Getting fuel to the cells is critical, and exercise is a method by 
which to construct and enhance the blood vessels. VEGF comes 
to the rescue by building more capillaries in the body and the 
brain. VEGF increases the permeability of the blood - brain barrier, 
which allows substances vital to neurogenesis into the brain during 
exercise. 
Finally, FGF - 2 is critical for neurogenesis. It helps tissues to 
grow in the body, and while it is in the brain it aids in LTP (Ratey, 
2008). 
All together, these repair factors prevent the damaging effects 
of chronic stress, keep the stress hormone cortisol in check, and 
increase the regulatory neurotransmitters (serotonin, dopamine, 
and norepinephrine) that keep you calm, positive, and energized. 
Exercise has also been shown to stimulate several genetic processes 
that enhance the health, longevity, and immunological functions of 
the brain. Exercise - stimulated transcription — the genetic process 
of constructing RNA from DNA — aids neuroplasticity, including 
the stimulation of BDNF, which enhances memory and promotes 
neurogenesis in the hippocampus. 
When blood circulation increases during exercise, the BDNF 
that had gathered in reserve pools near the synapses is unleashed. 
During exercise, IGF - 1, VEGF, and FGF - 2 push through the blood -
brain barrier, through the web of capillaries, and through the tightly 
packed cells that screen out intruders such as bacteria. These three 
hormones work with BDNF to increase the molecular processes 
that sharpen cognition and memory. 
Stem cells can divide into neurons or glial cells through a process 
enhanced by exercise. However, exercise alone won ’ t sustain the 
new neurons. Research has shown that exercise plus an enriched 
environment will allow you to keep the new neurons. In other 
words, you need mental exercise in addition to the physical exercise 
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to maintain the new neurons. Perhaps this is why some professional 
athletes are bright and some are less than bright. 
It has been shown that physical exercise, especially if it takes 
place in a new and stimulating environment, is an effective way to 
promote neurogenesis. Learning is critical because the development 
of new neurons takes place in the section of the hippocampus that 
is involved in new learning (memory). Thus, physical exercise and 
learning work together to stimulate neurogenesis. Exercise makes 
new stem cells, and learning prolongs their survival. The best exer-
cise therefore combines a cardiovascular boost and learning a new 
skill. 
Voluntary exercise seems to get the best results, because it is 
marked by the absence of stress and the inclusion of theta brain 
waves, which are present when you pay close attention to some-
thing. Theta waves are not present when you eat or drink or are 
functioning on automatic pilot. Voluntary exercise is not something 
you do mindlessly, out of habit; it is something you decide to do. 
Since your frontal lobe does the deciding, activating this part of 
your brain is a key part of neurogenesis. In other words, you can ’ t 
learn something new unless you make an effort and you are paying 
attention. 
In summary, there is abundant evidence that exercise can help 
you to learn, but the benefi t occurs after exercising, not during. This 
is because during high - intensity exercise, the blood is directed away 
from the PFC to enable the body to deal with the physical chal-
lenge. Because the PFC is the brain ’ s brain — the center of executive 
functions — it is necessary for learning. After you fi nish exercising, 
the blood shifts back to your frontal lobes, and with it you get an 
increased capacity for focus. Thus, as John Ratey suggests, don ’ t 
study for the Law School Admission Test while you ’ re on an ellipti-
cal machine at the gym. Wait to study until after your exercise ses-
sion to get the full benefi t. 
How can exercise be included in a school curriculum to help the 
students boost their learning skills? One example has emerged just 
west of Chicago in the Naperville school system, which initiated an 
exercise program in its curriculum in an effort to boost academic 
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performance and prosocial behaviors. When the eighth - grade class 
took the Trends in International Mathematics and Science Study 
(an international standards test that 230,000 students around the 
world also took), the class fi nished fi rst on the science section and 
sixth on the math section (after Singapore, Korea, Taiwan, Hong 
Kong, and Japan). To put these gains into perspective, note that 
50 percent of students in those Asian countries usually score in the 
top tier, whereas only 7 percent of U.S. students reach that mark. 
Thus, the Naperville students scored signifi cantly above the norm 
for the United States. 
Many factors account for these fi ndings. One could be that only 
6 percent of U.S. high schools offer physical education, or gym class. 
Another factor could be that American children spend an average of 
fi ve hours a day in front of a computer, a TV, or a handheld screen. 
The benefi t of exercise on learning has garnered the attention of 
some state education departments. The California Department 
of Education has shown that students with higher fi tness scores 
also have higher test scores, and it has also shown an overall posi-
tive infl uence on memory, concentration, and behavior in the 
classroom.
Exercise Medicine 
Exercise is good medicine, and a lack of exercise is bad medicine. 
Evidence for the variety of health benefi ts of exercise has been 
accumulating for more than fi fty years. 
Exercise has been shown to lower infl ammatory chemicals. For 
example, in an extensive study that examined the records of 13,748 
people over the age of twenty, it was shown that exercise can lower 
the infl ammation chemical C - reactive protein (CRP). The greater the 
amount of exercise, the lower the level of CRP. Only 8 percent of 
those who engaged in vigorous exercise had elevated CRP, whereas 
21 percent of those who did not exercise had elevated CRP. This 
benefi t can occur at all ages. When eight hundred men and women 
between the ages of seventy and seventy - nine were examined, both 
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moderate and strenuous exercise were associated with lower levels 
of CRP. 
Although a lack of exercise negatively affects stem cells in the 
brain and their differentiation into new neurons, so does excessive 
exercise. In contrast, both moderate and vigorous exercise support 
their development. The lesson here is that the extremes of no exer-
cise or excessive exercise do not promote a healthy brain. Exercise 
moderately and vigorously.