Something New Under The Sun: DNA & Exercise

February 10th, 2014 By Steven Knope, MD

“There is nothing new under the sun” is an idiom that dates back to biblical times. In some ways, it still feels true today. This is because much of human nature has not changed over time. If we pick up a newspaper we see that politicians are still lying, poverty is still with us and people are still being murdered every day – usually at the hands of someone they knew. On the positive side, we still see acts of heroism.

Last week, a 62-year-old neurosurgeon got stuck driving in a rare Alabama snow storm to operate on a critically-ill patient with a traumatic head injury. So he got out of his car and walked 6 miles to the hospital, where he saved the patient’s life. The neurosurgeon, Dr. Zenko Hrynkim, said that if the patient did not have surgery he would have died, “and that’s not going to happen on my shift.” So how does one person find the moral and physical strength at age 62 to walk 6 miles in a snow storm to save a life, while another backs over her boyfriend with a truck because he would not drive her to McDonald’s for Chicken McNuggets? (Also a recent headline.)

Nature vs. Nurture

When we see such contrasts in physical and mental capabilities, we inevitably find ourselves in a discussion about “nature vs. nurture.” Is it primarily their genes or their upbringing that cause people to behave the way that they do? This circular argument gets us no where, because we can’t really know the answer and because most of us just believe that it is a combination of both.

DNAHowever, what if we could work to change our DNA? What if we could activate beneficial genes and turn off undesirable genes ourselves, without genetic engineering or advanced medical technology? What if you could begin to change your very nature at the level of your DNA starting tomorrow? Wouldn’t that be something new under the sun? Well, it turns out that this is actually possible. To understand how this works we’ll need to dip our toe into the pool of science.

The Scientific Method

We have one very powerful tool for problem solving that our ancestors did not have. It is called the scientific method. Science may not seem new to you, but in the course of human history it most certainly is. It was as recent as 1860 that Luis Pasteur discovered the germ theory. Before this, people did not know that bacteria caused disease. Applied medical science was still in its infancy in the mid 20th century. DNA was not even part of our lexicon until the 1950s, when Watson and Crick unraveled the double helix.

The scientific method in not as complex as most people think. The scientific method is nothing more than a way to keep human beings honest. It is a way to remove bias from our thinking – a method to test seemingly logical hypotheses – to find the truth.

Where am I going with all this?

One of the greatest scientific discoveries over the past 60 years is that exercise is good for us. Exercise is an extraordinarily powerful agent in preventing and even treating many diseases. Exercise does far more than produce bigger and better-defined muscles. Exercise produces beneficial effects in virtually every organ in the body. Many of you are now living a deliberately active lifestyle, which was not part of life for your parents or your grandparents. If your ancestors were active people, it was due to the fact that they did physical labor to survive, not because they took up jogging to lose a few pounds.

Science has dramatically changed our understanding of exercise. Before the scientific method, exercise was considered dangerous for all but young children. Without this tool called the scientific method, doctors were ignorant about the effects of exercise on the body. When Dr. Kenneth Cooper, the Father of Aerobics, started doing cardiac stress testing in the 1950s he was called a heretic. He was brought before the Texas Medical Board and forced to explain himself. Doctors argued that if people over the age of 40 started exercising there would be dead joggers lining the streets.

Here’s the Big News

New experiments over the past year have shown that exercise literally changes our DNA. Read this sentence again. We now know that exercise, especially intense exercise, turns on and turns off certain genes in our DNA, thus altering who we are at the genetic level.

So this question of nature vs. nurture may soon lose relevance. If our very DNA can be changed by a behavior – such as exercise – then this notion that we are a slave to our genetic endowment must be reexamined. This is how science works. As new information becomes available, our models for understanding the world change.

When DNA was first discovered, we believed that it was an unalterable template for our lives. At the same time, based upon the available evidence, we believed that we were born with a fixed number of brain cells and that we could not form new brain cells in adulthood. Neither of these things turned about to be true. Behaviors like exercise have been shown to activate specific genes that change the structure and function of our existing cells. Exercise can also cause new brain cells to form. It turns out that there are stem cells in the brain that can produce new cells, provided that you apply the right stimulus. Studies in mice have shown that exercise can trigger the formation of brain cells in the hippocampus, an area critical for memory.

The Mechanism of Change

How can exercise change our DNA? One of the chemical methods that the body uses to alter our DNA is something called DNA methylation. Methylation is a process by which a carbon molecule with some hydrogen molecules (a methyl group) tags a gene to either turn it on or turn it off. Scientists can now take samples of the DNA from a person, have them exercise, and then measure the changes that occur in their DNA as a result. And the number of these changes is impressive. Furthermore, it has been postulated that some of these changes in our DNA are long-lasting and may even be passed on to our offspring.

“Athletes are not normal!”

A few years ago, I called a well-known cardiologist about a mutual patient. The patient was in his 70s, had always been athletic, and now had an abnormal stress test. However, his stress test did not become abnormal until he exercised at a high level, something that he had done all of his life. When I spoke to the cardiologist, a large and unfit man, he asked, “Why did you exercise him so hard?” I responded, “That is what he does when he exercises every day. If I had not allowed him to do what he normally does, you wouldn’t have seen these changes in his EKG.” In an exasperated tone he said, “Athletes are just not normal!” He was clearly irritated and considered such behavior bizarre.

And we are now learning why athletes are abnormal. They appear abnormal on the outside because they are abnormal on the inside. I would argue that these “abnormalities” are desirable. You don’t have to be an elite athlete or kill yourself to become more desirably abnormal. All you have to do is start moving your body with a plan and with a purpose. And if you do so, and if you keep doing it, you will change yourself from the inside out. Changing your DNA for the better will make you a happier and healthier person than you are now. The alternative, of course, is to remain “normal” – like the overweight, sedentary cardiologist. However, I wouldn’t bet money on that guy reaching the hospital to save a patient in a snow storm…

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