Too Much of a Good Thing

Posted by Inside Trail Racing in Blog, Uncategorized on Feb 4, 2015

Exercise is good for you, but there can be severe consequences in demanding too much from a body designed for moderation.


As more insight and research is conducted in the field of exercise physiology, old ideas are discarded and the public gets to feast over new controversies in data while the verdict is still out. These days the internet is rife with articles describing the relationship between exercise duration and health. The concerning subject being that too much cardiovascular work could result in major health complications or even death. While scientists are consumed with determining guidelines for how much is too much, it is generally accepted that exercise needs to occur on a regular basis for twenty to thirty minutes at a time to receive any health benefits, and that aerobic exercise is safer than anaerobic exercise. As most ultra-runners can attest, skimming by with such brief workouts will not be adequate in pulling them through a hilly 31.5-mile (or longer) race. And as more and more people sign up for marathons and ultras, it might be a good time to find out if ultra-endurance sports are even really good for you. Can something that provides so much pleasure and health benefits really have such a dark side? Are certain individuals, such as those who are over 60-years-old or have a family history of hypertension, more at risk? Should everyone who is interested in ultra-endurance sports have a physical workup completed before they begin training or should they have their genes profiled, as well? What positives can outweigh the risk involved? Should we be cautious in how we interpret the data, and is it possible that the recent findings are manipulated depending on how we want to interpret them? These are questions that may take some time to be able to answer in full and with conclusive evidence, however, the following presents some physiological and psychological ideas to be aware of as one makes the decision to maintain mileage.

Before all of you die-hard ultra-runners turn away, let’s examine some of the greatest benefits to being on the feet for hours. We have to remember that we are not just humans but we are the human animal. Like other animals, we are born with bodies that, through the pressures of environment and time, adapted to cope with the context in which we live. It is obvious that exercise is good for you: it decreases your risk for metabolic and cardiovascular diseases, increases strength and endurance, boosts energy levels (when coupled with adequate recovery), supports and enhances neurogenesis (generating new neurons), replaces bad moods with better ones. Regardless of supermarkets and desk jobs, we are still biologically bipedal hunters with a strong cardiovascular system and moderately sized muscles made for wandering and running long distance. We evolved high order problem solving skills, patience, emotional regulation, and the ability to outrun even a horse in a marathon because being totally impulsive and sprinting just didn’t coincide with our divergence from other apes. We are equipped to move over differing terrain for hours as long as we have enough sugar in our blood to fuel the journey. Our insulin production, glycogen storage and mobilization are markers for how we have this amazing, unrivaled capacity for endurance. As a social species with general corporeal fragility when compared to a lion or rhinoceros, humans rely on both each other and tools; humans have developed the need for psychological synergy as protection and guaranteed genetic replication. Exercise, when done with others, creates a pillar of support by feeling connected to and accepted by friends. Those who frequently participate in athletics have more extroversion, optimism, and healthy coping mechanisms than those who don’t, and it can satisfy the need for achievement even when a competition doesn’t exist. When a sport is important to us and has intrinsic meaning, we feel happier doing it and sullen when it isn’t available.

Finisher at the incredibly arduous Hardrock 100-Mile Endurance Run.

Finisher at the incredibly arduous Hardrock 100-Mile Endurance Run.

Now to burst your bubble: Research currently indicates that maximum cardiovascular gains are only obtained at the moderate range of both intensity and duration; the benefits of exercise are lost, and risk heart problems increases, with too much high intensity and/or prolonged efforts. Studies in Germany and Sweden followed over 1,000 participants with stable coronary heart disease for ten years and assessed the frequency and level of their activity efforts. The study group consisted mostly of individuals over the age of 60 and who were instructed to exercise regularly as part of their rehabilitation program. They were divided into groups with differing activity guidelines with three of them exercising at low to high frequency and one sedentary group. Those who were physically inactive were twice as likely to suffer a heart attack of stroke than those who were active, but what they also found was that those individuals who did the most exercise were more than twice as likely to die of a heart attack or stroke. The study in Sweden assessed 44,000 men between the ages of 45 and 79 and tracked their heart health for 12 years to discover if any irregular heart rhythm (atrial fibrillation) developed, which has been determined to be a stroke risk factor. Their results concluded that men who participated in intense exercise for more than 5 hours per week were 19% more likely to develop atrial fibrillation by the age of 60, while those who spent less time exercising had no increase in risk. To be sure, those who did 5 or more hours of mild to moderate intensity exercise were 13% less likely to develop any irregularities than those who were sedentary.

stressA Very Brief Lesson in Stress

Even without studies to provide us with numbers, there is the basic fact that the sympathetic nervous system—which is designed to become active in times of stress to facilitate easy escape from danger—eventually breaks down tissues and suppresses important hormones if turned on too often. During prolonged physical activity or high intensity work, the “feed and breed” parasympathetic nervous system state is suspended. We shift from being relaxed, digesting, copulating, pondering people to alert, anxious, attention-sharpened freaks. Testosterone, estrogen, luteinizing and follicle-stimulating hormones, which are necessary for reproductive and metabolic health, are suppressed because they are a cost the body cannot afford during stressful situations. Steroid hormones, such as adrenaline, noradrenaline, and cortisol are churned out by the adrenal glands, which have been stimulated to release them by other hormones with fancy names (adrenocorticotropic hormone (ACTH) and corticotropin-releasing hormone (CRH) if you just need to know) produced in the pituitary and hypothalamus glands within the brain. The stress response is an adaptive mechanism that is necessary when immediate trauma or danger exists, but we evolved an intelligence that allows quaint conception of doom to successfully turn on the adrenaline, along with athletic extremism, which accomplishes the same feat. To escape a predator, your body needs to put its energy into fleeing the scene or fighting back. That big breakfast you ate doesn’t feel so nice if you have to dig deep to make it to a safe zone, and maintaining an erection or releasing an egg would really be ridiculous when you may perish within minutes, not even living long enough to make any babies. So the brain blocks the release of reproductive/vegetative digesting hormones and everybody feels asexual and loses their appetites. Once the stressor retreats or we start thinking about something pleasurable, the system is no longer inhibited and we become normal animals subconsciously guided by the need to procreate. Good. The body recovers.

The mind is a machine that takes in information to build a representation of the world. Our fears can be largely fabricated triggering the stress response and the negative consequences of it, however, as mentioned above, exercising for multiple hours per day induces the same problems. Adrenal fatigue, reproductive inhibition, and loss of muscle and bone mass are a direct result of demanding too much from the body. Pushing past the discomfort of a hard workout is beneficial when those efforts alternate with adequate recovery and the workout is restricted by short to moderate duration. When you’ve been running for hours, your body’s systems are depleted, chugging along out of survival because some crazy person decided they found they can not only stay up for 24 hours without sleep, but that can actually run for 24 hours without sleep, too! Forcing the body to keep going when it wants to stop is not without consequence. It takes you into that stress response system because your body functions really do begin to suffer and you need to survive. There are many young talented athletes who have had to abandon their careers early because of heart attacks or kidney failure caused by Rhabdomyolysis (the breakdown of skeletal muscle tissue entering the bloodstream, whereupon certain proteins that are harmful to the kidneys induce electrolyte disturbances, abnormal heart rate, and overall weakness). Are these salient cases or a trend we will be seeing more of as there is more interest and participation in ultra-endurance sports? It is my opinion that the human body is capable of long-distance, long-duration exercise, but that the increase in ultra events completed over the year by athletes of all ages hasn’t been studied enough. The benefits of exercise are well established, meanwhile, the repurchasing of too much exercise is still unknown. There is a risk to any sport played, but there are also measures to take to buffer oneself from those risks. I recommend enforcing many days of rest or active recovery after long or intense activity; eating more protein (whey or animal protein is best) to combat muscle damage and taking an iron supplement; getting monthly or biannual physical checkups; limiting the number of ultra events attempted per year; keeping children out of ultra-endurance sports. A child should not undergo any kind of stress that will suspend hormone production or disturb the development of the endocrine and cardiovascular systems, to name a few.

Volunteers at a Bay Area trail racing event encourage each runner to keep going even when they think they can’t.

Volunteers at a Bay Area trail racing event encourage each runner to keep going even when they think they can’t.

Back to the Ultra Utopia

One of the most encouraging elements of ultra-endurance sports is the community and care of those involved. The support and optimism offered and received is unlike any other sport, and though ultra-running is not a team sport, the cheers and appreciation for fellow runners creates a definite club in which one can feel limitless—part of something positive, far-reaching, and fulfilling. Whether or not it is physiologically the healthiest activity, the psychological health it can provide is profound. For some, it has refashioned their lives completely, ending addictions to sugar, alcohol, or nicotine; alleviating grief or isolation; contributing to a greater sense of self or identity. In my 8 years time working with endurance athletes, I have seen people become who they want to be, and even more beautiful, I’ve seen them altruistically motivate and help others become who they want to be, as well. The value we place on what we do, the intrinsic meaning, the extrinsic approach, has serious implications in both performance and well-being. Not everything we do is good for us, but sometimes it isn’t a cost-benefit analysis, it is just simply something that makes us feel whole, connected, and confident, facets of the social edifice of life that has just as much importance as eating healthy, not smoking, and getting a moderate amount of exercise.

Written by Tanya Stahler

3 Responses

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  3. Annita Carra says:

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