Marathons and Our Bodies

Facts and Musings to Consider Before Deciding to Run a Marathon

by by Mara Renz Smith

illustration by by Robert Sandler

The idea that there are health benefits to pushing our bodies past their limits is pure myth. Our bodies, organic gifts, are not mechanical structures that can be easily tuned and replaced. Once-injured scar tissue can linger for a lifetime and although surgical repairs abound, we do not yet live in the age of the bionic man. Science has shown that extreme forms of exercise, such as running marathons are not actually healthy. Subjecting your body to extreme pain and overuse, suppresses the immune and antioxidant system, and increases inflammatory response, as well as scarring and fibrosis of the heart. In the body’s desperate attempts to keep the heart beating at the greedy levels we want it to. Why do we ask so much of our body?

The first couple miles of a marathon, for an experienced runner, might feel like a joyride. The energy from stored sugars easily slips from muscles into comfortable strides. Breath deep, the body slowly warms to flushed glow. Heaving flesh floods with blood in broad tides. The antioxidant system increases its work, combing the body of free radicals. The body now purified. Cleansed.

The creation of energy from material flesh. Slow steady burn of acid. Stream of easy energy from stored sugar fades to a trickle. The brain starts to slow. The consumption of the body. First fat. Stores slowly drain. Body reeling for energy starts burning muscle, cannibalistic, breaking down hamstring, bicep, and heart, without discrimination.

Body in paradox. Exhaustion sets in. The body asks for rest. Conquer the self, tame the body. The heart starts to scar, to protect it's fabric with thick fibers, toughening against trauma inflicted by the will. Antioxidant defenses now suppressed. Factory output of free radicals at maximum, they rome the body unrestricted. DNA mutated, left unfixed. Inflammation, wild fire flaring with each desperate pump of the heart.

The body forgets as it struggles to meet the demands of the spirit. The brain now starved, sputtering. Push past pain regardless. Push to be strong. Push to be determined. To feel immortal.

Cross the finish line to the next stage: recovery. Bits of torn heart float in a daze through blood thick with acid. Body filled with free radicals. The effects of a wartime economy: immune and antioxidant defense reeled down to minimum.

Maybe there will be euphoria, a deep sense of triumph over the self. Proof of strength. Determination. Pedal down hard, stepping out with smiles, ignoring the steam pouring from the hood.

Maybe the heart won't find its fabric scarred and hardened. Maybe DNA escapes the electron air raid of the free radicals without consequence. Maybe the body will work just as well as it did yesterday. Maybe. This is the body on extreme exercise. Welcome to the world of the marathon.

I underwent my first orthopedic surgery on my ankle by the time I was 16 and a second mirrored procedure at 18. I was confined to bed rest. Twenty extra pounds of muscles, red tissue that had been alive with blood and health, withered into white lipidy soup. By the time they took the cast off, from the knee down, there was nothing but a shriveled up piece of bone with some slabs of skin wasted to weird wobbly flesh that refused to react to any effort of will. Five years later and some mornings you can still hear the chorus of my various treated and untreated injuries accumulated from four years of athletic training, a combination of ankles, hips and knees, that pop, crack, and groaning with every step.

Is the ability to ignore our body's warning messages really a sign of personal strength? Why do we feel compelled to prove strength of will over flesh? A mastery over the body led to my own self-inflicted mutilation. I wish someone had been there to tell me: if it hurts that bad, for god's sake, stop running. Pushing through pain means pushing through your own flesh: ripped tendons, ligaments, and muscles.

The benefits of living an active lifestyle are plentiful. Getting up and using your body for what it was made to do, to move throughout the world, is what will keep it healthy. This keeps the body agile, strong, this simple movement protects the brain and nervous system by promoting the filtering effects of our antioxidant system, which removes free radicals from our system, protecting our DNA, leaving us with a healthy body and a healthy mind. The movement of the body protects the psyche, helping stave off depression, anxiety, and stress. Exercise helps delay the onset of dementia and the process of aging. It keeps our bones healthy and dense, our muscles springy and layered, our heart strong and efficient. But these benefits only exist if we can keep that up. You have to be active throughout your whole life to receive the benefits of exercise. It must be sustainable.

The body is a resource of mobility, of health. The reckless, self-inflicted punishment on the body reduces the ability to exercise later in life. Joint injuries are common in extreme endurance exercise. With each joint injury comes an increased risk of developing osteoarthritis, the joint's worn down cartilage and excessive scar tissue preventing the normal cushioning of bone and limiting your potential to maintain an active lifestyle.

Under normal conditions of life, the body produces supercharged ions that are incredibly reactive, eager to shed their charge. These are called free radicals and are the normal byproducts of a cell's energy use. Their tendency to "give up" electrons leads to chemical reactions that can include reactions with DNA that produce kinks in the double helix that prevent genes from being read correctly or whole deletions of genes that change the composition of the protein that a gene makes. The body has machinery to correct these mutations, to maintain our DNA. The body also keeps a force on the offensive, the antioxidant system, a unit of molecular machines designed to eliminate free radicals before they can damage DNA.

There is a clear difference between the heart healthy benefits of the regular exercise schedule that is recommended for training for a marathon, and the actual race day itself. Under extreme conditions produced by running a marathon, the level of free radical exposure is abnormally high and the body can't keep up with the amount of antioxidant defense and DNA repair necessary to maintain our genetic health. Running a marathon at a Olympian two-hour pace requires a 15-fold increase in the body's energy metabolism. Even at a layman's four-hour pace the body must maintain an extended 10-fold increase in metabolism, and thus must deal with a 10-fold increase in free radical byproducts. Instead of increasing levels of antioxidant defense to those needed to neutralize the free radical produced, the antioxidant defense system is suppressed as the body focuses all of its energy on survival, on keeping the heart beating. This increase in free radicals combined with the body's reduced ability to protect its DNA increases the risk of developing changes in DNA that are associated with diseases such as cancer and sporadic forms of neurodegenerative disease like ALS, Parkinson’s Disease, and Alzheimer’s, as well as an increased rate of aging.

In addition to risking DNA damage, running a marathon can also negatively impact heart health. Blood levels of heart protein are elevated post marathon, similarly to someone who has just sustained a heart attack. Although this increase in heart protein levels has not been clearly linked to heart damage, recent evidence has unveiled an increased incidence of heart muscle scaring in older athletes who appear to be in great health. There has also been evidence of an increased rate of "fibrosis" in aged marathon runners, a build up of collagen fibers along the heart muscle. This enlarges the heart, causing it to become stiffer and putting the runner at a greater risk of developing abnormal heart rhythms. In a study, mice that were subject to an exhaustive workout schedule simulating marathon-like conditions had significant scaring and fibrosis of the heart compared to more leisurely exercised mice. The link between heart health and exercise isn’t linear, so the increased mileage gained from marathon running does not give a person additional protection. Rather, increasing your workout schedule to an exhaustive one can have a negative health impact.

Marathon running has become increasingly popular in the United States over the past several decades. In 1976 only 25,000 Americans ran a marathon, while in 2010, participation increased to over 500,000. Many people assume that pushing the body to it's limit is the epitome of good health. With increasing numbers of people participating in marathons for perceived health benefits, it is vital to make the recent discoveries in science easily accessible, so that potential marathon participants have a chance to consider the potential risk. The human body is a beautiful product of 500,000 years of evolutionary engineering. Our bodies not only reward us with mobility, but they also protect our mind and spirit, and deserve to be protected in turn.

MARA RENZ SMITH B '13 cautions you.