Body by Science

McGraw-Hill

Contents

Chapter One

Strange as it may sound, fitness is a state that lacks a precise definition. Most of us use the term without really knowing what it is we're talking about. The fitness industry offers no definitions, nor does the medical industry.

A similar problem arises when one attempts to obtain a valid definition of health. In preparing to write this book, we looked extensively into the scientific literature, including many medical textbooks, to seek out a definition. We were surprised to discover that the terms health and fitness—while bandied about liberally within the fields of medicine, health care, and physical training—have never been given a universally agreed-upon definition. When examining his textbook from medical school, The Pathologic Basis of Disease, Doug discovered that while this book had no difficulty defining pathology, it never once presented a definition of health.

The balance of catabolism and anabolism

People routinely refer to health and fitness as if the two concepts were cojoined. The popular assumption is that as one's level of physical fitness rises, the level of health rises along with it. Unfortunately, no direct scientific link between these two conditions exists. The human body, you see, is never static; it is a dynamic organism that carries on a perpetual balancing act between breaking down (catabolism) and building up (anabolism). This is how your blood-clotting system functions, for example. It is continually breaking down and building up clots, keeping a balance between your blood viscosity and coagulability to ensure a smooth flow and still stem any bleeding that should occur (but not so aggressively as to produce clogged arteries and infarcts). Your pH balance, blood gases, hormone levels, electrolytes, fluid levels, and innumerable other complex processes are constantly shifting and changing as well within these catabolic and anabolic processes. Life, in essence, depends on this precise balance between a catabolic state and an anabolic state, and this balance is what defines the health of the organism.

In brief, these states can be summarized as follows:

Catabolic: Anything that results in the breakdown of the organism.

Anabolic: Anything that results in growth and differentiation of the organism.

Looking back at our species' hunter-gatherer days, we know that there were long periods when starvation was a real threat. During those times, a catabolic state would have predominated. Despite the obvious negative effects, research into calorie restriction and life extension has revealed that during such catabolic states the vast majority of DNA repair occurs. The lesson here is that a catabolic state is a necessary component of health, rather than something to be avoided. Knowing this, we must factor the catabolic and anabolic processes into any definition of health that we create. Health implies a disease-free state, and so the definition must acknowledge this component as well. Thus, given the lack of a working definition from the fitness and medical worlds, we cautiously offer the following:

Health: A physiological state in which there is an absence of disease or pathology and that maintains the necessary biologic balance between the catabolic and anabolic states.

The body's ability to sustain this balance between the catabolic and anabolic states manifests in an ability to make adaptive adjustments, thereby allowing for survival. Each and every day, your body must face numerous challenges, such as exposure to the various elements, muscular exertion, and the presence of pathogens. If it does not successfully adapt to these challenges, it is ill equipped to survive. Fitness, then, can be said to be the body's ability to withstand, recover from, and adapt to environmental threats in the form of stress-producing agents that act upon the organism. Or, stated another way:

Fitness: The bodily state of being physiologically capable of handling challenges that exist above a resting threshold of activity.

What is exercise?

To fully understand the relationship among exercise, fitness, and health, it is necessary to know precisely what exercise is, as opposed to mere physical activity. The important distinction is that exercise is purposefully directed activity that stimulates the body to produce a positive adaptation in one's level of fitness and health. Physical activity in general, while yielding the potential to produce certain adaptations in one's fitness and health, can unfortunately also undermine one's health. Therefore, we advance the following as our definition of exercise based on known facts:

Exercise: A specific activity that stimulates a positive physiological adaptation that serves to enhance fitness and health and does not undermine the latter in the process of enhancing the former.

Thousands of activities are popularly thought of as exercise, ranging from walking and running to calisthenics, weight training, and yoga. However, many of these activities do not qualify as exercise by our definition, either because they are inefficient at stimulating the mechanical and metabolic adaptations necessary to benefit the fitness (and, to a large extent, the health) of our bodies or because their continued performance results in an undermining of bodily health.

It is for this latter reason that we must exclude activities such as jogging and running from being considered as exercise. This determination may be upsetting to some, particularly those who run or jog, but the hard truth is that those who select running as their modality of exercise are taking a huge risk. Studies have documented that 60 percent of runners are injured in an average year, with one running injury occurring for every one hundred hours of performance.

The damage caused by running will often manifest after a period of fifteen to twenty years of performing the activity, such as when runners who started in early adulthood reach the age of forty or fifty and find that they are no longer able to climb a flight of stairs without their knees aching; or they experience difficulty in lifting their arms above head level because of osteophytes (bone spurs) that have formed in the shoulder joint; or they can't turn or bend anymore because of chronic lower-back pain. These are progressive conditions, rather than immediate ones, and are consequences of inappropriate activities and activity levels that are chronically catabolic and are performed far too frequently to allow an anabolic state to manifest.

Even activities that are considered "mild" can become problematic in this respect. For instance, the thousands of rotations of the shoulder and elbow joint that take place over a career of playing recreational tennis can lead to osteoarthritis, even though the actual weight being moved in a tennis racket is modest. Any activity that is highly repetitive has wear-and-tear consequences that will sooner or later override the body's ability to recover and repair itself. If these types of activities are performed frequently (many times a week), they will typically manifest sooner.

Health and fitness-what's the connection?

When we looked at the scientific literature, we found not only a lack of definition for fitness and health but also, and even more surprising, a minimal (at best) correlation between exercise and health.

Many people have it in their minds that athletes are healthy because they are fit. However, if you look across the board at the professional level of sport, and if you analyze the statistics and health profiles of these athletes, you will find that, while they have supranormal levels of fitness, the means they employ to achieve this level of fitness may actually undermine their health. Most athletes who compete at a world-class level do not achieve that level of world-class performance in a way that enhances their health, and this is simply because it is not possible to do so. This is particularly the case if the sport in question is looking for a level of physical performance that is not necessarily part of the natural evolutionary background of our species.

A classical example is the tale of Euchidas, which comes down to us from the famed Greek historian Plutarch (C. A.D. 46–A.D. 120). After a Greek victory over the Persians at the battle of Platæa in 479 B.C., Euchidas ran to Delphi and back:

... Euchidas of Plaæa, who promised that he would fetch fire as quickly as possible, proceeded to Delphi. There he purified his body, and having been besprinkled with holy water and crowned with laurel, took fire from the altar, set off running back to Platæa, and arrived thereabout sunset, having run a distance of a hundred and twenty-five miles in one day. He embraced his fellow citizens, handed the fire to them, fell down, and in a few moments died.

And then there is the oft-told legend of Euchidas's contemporary, another distance runner named Pheidippides, which was originally reported by the Greek historian Herodotus (c. 484 B.C.–C. 425 B.C.), and transmitted to future generations by Roman historians such as Lucian (C. A.D. 125–after A.D. 180).4 According to the legend, a Greek runner by the name of Pheidippides ran in excess of 145 miles (from Athens to Sparta) in roughly twenty-four hours, which was quite a display of ultraendurance athleticism. Pheidippides followed up on this feat by running an additional twenty-six miles from Marathon to Athens to announce the Greek victory. When he reached Athens he proclaimed (depending upon which ancient historian you read) either "Nike!" ("Victory!") or "Be happy! We have won!" Regardless, the ending to this tale is the same as that of Euchidas's: Pheidippides then fell to the ground—dead.

It's little wonder that an athlete's health would be gravely impaired by such an activity. According to the account of Herodotus, in that first run, from Athens to Sparta, Pheidippides completed the equivalent of back-to-back ultramarathons totaling more than two hundred kilometers.

Even more mind-boggling is the fact that, rather than being put off the notion of running such distances because of the health dangers, people instead raise monuments to the memory of Pheidippides by staging "marathons" and even the International Spartathlon race, which has its athletes running over purportedly the same 147.2-mile route from Athens to Sparta. To no surprise, some modern extremists in the realm of fitness have either met the same premature end as their Grecian counterpart (such as the author and running guru Jim Fixx) or suffered a host of ailments that are not compatible with long-term health and survival. The scientific literature is filled with data that strongly make the case that long-distance runners are much more likely to develop cardiovascular disease, atrial fibrillation, cancer, liver and gallbladder disorders, muscle damage, kidney dysfunction (renal abnormalities), acute microthrombosis in the vascular system, brain damage, spinal degeneration, and germ-cell cancers than are their less active counterparts.

Unaware of the anabolic/catabolic relationship, or that the pursuit of fitness can result in decidedly negative health consequences, most people still associate fitness (or exercise) with health. Instead of recognizing health as a delicate balance of opposite yet interrelated processes, they believe it to be something that is expressed across a broad continuum that never caps out. They assume there are increasing degrees of "better" health, as opposed to picturing health as the absence of disease. In reality, fitness and health are not extrinsically linked; as one goes up, the other does not necessarily go up with it.

With the correct modality of exercise, health and fitness can in fact track along together, at least to a point. However, simply performing physical activity can create a physiological situation whereby fitness levels rise, but health actually declines. This is the consequence of attempting to drive a level of specific metabolic adaptation for fitness that results in an imbalance between the anabolic and catabolic states.

We evolved as an organism that had to expend energy to acquire energy. This was the work-based way by which we acquired food and shelter to survive. It required a minimal level of activity, with intermittent high levels of muscular exertion and intensity. A balance was struck between the catabolic state that was a by-product of the exertion necessary to sustain ourselves and the anabolic state of being able to rest and recoup the energy required to obtain the nutrition needed to fuel the activities involved in our survival.

Fast-forwarding to our present-day situation, rather than a food paucity, there is a food abundance, and laborsaving technology relieves us from needing to expend as much energy to obtain that nourishment. As a result, there has been a compromise in our health that is the exact opposite of the problem that the endurance athlete faces; that is, there is now a huge portion of the population whose physical activity is of such low intensity that catabolism doesn't occur to any meaningful extent. There is no mechanism by which to drive a physiological adaptation for health or fitness.

It has been assumed that physical activity, per se, is responsible for health enhancement, but that assumption is flawed at the core. Such "health" benefits as might occur result only from one's current activity levels being so subnormal compared with our species' DNA blueprint that even a slight increase in activity produces some improvement. Raising one's muscular effort from a near sedentary state to a level slightly closer to what our species' DNA has encoded over tens of thousands of years (and which has changed significantly only in the past forty or fifty years) is by no means an optimal route to health.

People who believe that there is a constant and linear relationship between fitness and health are akin to a person who decides to measure water levels while standing at the beach. He takes the first measurement at low tide. When he sees the tide turn, he takes another measurement and notes that the tide rose five feet in twenty minutes. He checks it again and discovers that it has now risen fifteen feet in thirty minutes. He then concludes that in two weeks, the whole continent will be underwater.

This is the nature of the mistake we make when we observe increased activity levels supporting a slight upward tracking in the improvement of health. Health will improve—but only up until it rises to a normal physiological baseline. One thing that quickly becomes apparent from studying the scientific literature on overly active groups such as extreme-endurance athletes is that, in their quest to achieve higher and higher tiers of dominance in their field by extending their physical activity level to its limit, it is entirely possible (and probable) that the methods they typically employ in their training, combined with the rigors of long competitive seasons, will result in serious compromises in their health and shortened life spans.

The good news is that science now has a better understanding of how the human organism adapts and recovers. With that understanding comes the knowledge that it is possible to participate in a form of exercise that produces supranormal levels of fitness without compromising health and that, in many ways, serves to enhance health. This scientific knowledge has been gained through rational analysis, understanding, and application, based on the variables of volume (amount of exercise), intensity (effort and energy expended), and frequency (how often the activity is performed). When applied to an exercise program, these findings can result in the achievement of supranormal levels of function, in terms of fitness, while simultaneously maximizing health so that it reaches its natural peak.

The quest for longevity

As we grow older, we naturally desire to grow older still. In this pursuit, we associate life with health, and health with fitness. So, it seems natural to inquire as to what exercises, what nutritional supplements, and even what drugs are available to aid us in our goal of living longer. It should be acknowledged that longevity, as with fitness, is not necessarily linked to health. It can be, but the important thing to remember is that health is ultimately linked to DNA—the self-replicating molecule that creates our bodies. The purpose of the body from the DNA's standpoint is merely to function as a vehicle to carry it forward into the future.

In our species' hunter-gatherer days, health was important to the degree that it allowed us to survive, as what brought us down most of the time were environmental factors such as disease, predators, childbirth, and trauma. Those are events that occur irrespective of one's level of fitness. Only through the application of human intellect and technology did longevity ever become an issue, or ever have an opportunity to track along with health.

(Continues...)

Excerpted from Body by Scienceby DOUG McGUFF JOHN LITTLE Copyright © 2009 by Doug McGuff and Northern River Productions, Inc.. Excerpted by permission of McGraw-Hill. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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