Bigger Brains, Better Genes - Exercise Benefits

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Bigger Brains, Better Genes

Sweat Your Way to a Bigger Brain

Believe it or not, those are among the benefits of exercising more

and eating healthier.

http://www.msnbc.msn.com/id/20746682/site/newsweek/

WEB-EXCLUSIVE COMMENTARY

By Dean Ornish, M.D.

Special to Newsweek

" Go pump some neurons! Expand your craniums! "

—Robin , in " Mrs. Doubtfire "

You don't need to read this column to know that exercise is good for

you. You probably already know that regular, moderate exercise is

one of the best things you can do for your health and well-being.

What you may not know is that new research is showing that exercise

beneficially affects your genes, helps reverse the aging process at

a cellular level, gives you more energy, makes you smarter, and may

even help you grow so many new brain cells (a process called

neurogenesis) that your brain actually gets bigger.

Really.

So does improving your nutrition. A diet high in sugar and saturated

fat diminishes neurogenesis, whereas other foods increase it,

including chocolate (in moderate amounts), tea and blackberries,

which contain a substance called epicatechin that improves memory.

Small amounts of alcohol increase neurogenesis, whereas larger

amounts decrease it. Chronic emotional stress decreases

neurogenesis, but stress management techniques increase it. Drugs

such as nicotine, opiates and cocaine decrease neurogenesis, whereas

a study published in the Journal of Clinical Investigation in 1995

showed that cannabinoids (found in marijuana) increase it, at least

in rats. (Uh, what were we just talking about?)

Use It or Lose It

Until about nine years ago it was thought that you were born with a

certain number of neurons, and they tended to decrease in number as

you got older. The best you could hope to do was to slow the rate at

which you lost brain cells.

Fortunately, it's not true. Researchers at the Salk Institute for

Biological Studies and at Columbia University showed that older

adults continue to generate new neurons at virtually any age.

Earlier this year these researchers found that in addition to

growing new neurons, exercise doubled blood flow to the brain. A

study published last year by researchers at the University of

Illinois reported that just walking for three hours per week for

only three months caused so many new neurons to grow that it

actually increased the size of people's brains.

Best of all, the region of the brain that grew the most was the

hippocampus, the part most involved with memory and cognition. After

only three months, those who exercised had brain volumes typical of

people who were three years younger! Also, the new neurons tend to

find their way to well-established existing connections and replace

ones that are damaged or nonfunctioning. Those who showed the most

improvement in fitness also showed the greatest enhancement in

memory. The authors concluded, " These results suggest that

cardiovascular fitness is associated with the sparing of brain

tissue in aging humans. Furthermore, these results suggest a strong

biological basis for the role of aerobic fitness in maintaining and

enhancing central nervous system health and cognitive functioning in

older adults. "

Regular, moderate exercise (along with healthier eating and stress

management techniques) also reduces inflammation throughout your

body, including in your brain, and reduces the incidence of tiny

strokes that can impair your ability to think clearly. Exercise also

helps boost your sense of well-being. Levels of beneficial

neurotransmitters such as dopamine, serotonin and norepinephrine are

higher in those who exercise—the same ones elevated by many

antidepressants. These, in turn, may help reduce depression, elevate

mood and help you focus better.

Exercise Makes You More Intelligent

Other studies have shown that older adults who exercise regularly

have better memory, are better at going from one mental task to

another, and can focus and concentrate better than those who are

sedentary. In other words, exercise makes older people more

intelligent.

Exercise makes younger people smarter too. Kids who exercise have

fewer problems with attention-deficit disorder and learn faster.

Studies have shown that physical education in schools improves

academic performance as well as physical fitness. For example, a

study by the California Department of Education of 322,000 seventh-

grade students found that the most fit scored in the 66th percentile

on their SATs, whereas the least fit scored in the 28th percentile.

Studies at the University of Illinois also found that those who were

more fit had better standardized test scores.

Exercising Your Genes

Your genes are not your fate. The choices you make each day in your

diet and lifestyle have a direct influence on how your genetic

predisposition is expressed—for better and for worse. You're only as

old as your genes, but how your genes are expressed may be modified

by exercise, diet and lifestyle choices much more than had

previously been believed—and more quickly. For example, Finnish

scientists reported in a study published in July that increased

moderate to vigorous physical activity modified two genes involved

in type 2 diabetes and reduced the risk of developing the disease,

independent of changes in weight or diet.

Another recent study compared mitochondria in muscle biopsies of

older and younger men and women. Your mitochondria are the " energy

generators " of your body's cells. One of the reasons many people

feel less energetic as they get older is that their mitochondria

work less efficiently with age. The investigators found that in

those who were mostly sedentary, mitochondrial function declined

markedly with age and was affected by more than 300 genes. Then the

investigators put these older men and women through a six-month

exercise program that involved strength training for one hour only

two days per week using the types of weight machines found in most

gyms. Resistance exercise for each session consisted of three sets

of 10 repetitions for each of: leg press, chest press, leg

extension, leg flexion, shoulder press, lat pull-down, seated row,

calf raise, abdominal crunch and back extension, and 10 repetitions

for arm flexion and arm extension.

After only six months, the subjects' strength improved by 50

percent, and they reported feeling much more energetic. Many of the

300 genes that had declined with age began to now act more like

those in younger people. In fact, the investigators found that

exercise affected age-associated gene expression more than in

younger people, meaning that exercise is especially beneficial as

people get older.

These high-tech studies illustrate what a powerful difference low-

tech interventions such as changes in exercise, nutrition and stress

management techniques can play in our lives. People often believe

that advances in medicine have to be a new drug, a new laser or a

surgical intervention to be powerful—something really high-tech and

expensive. They often have a hard time believing that the simple

choices that we make in our lives each day—how much we exercise,

what we eat and how we respond to stress—may make such a powerful

difference in our health, our well-being, and even in our brains.

But they often do.

How to remember to exercise in a way that's sustainable? Do what you

enjoy, make it fun and do it regularly. If you grow new neurons,

then you won't forget!