by Ryan A. Hall, originally presented at the 2003 SuperSlow Medical Resource Symposium

Introduction

Scientifically, stress is defined as the nonspecific responses of an organism to any demand made upon it (Selye, 1974). Viewed in this light, exercise is nothing more than a physical stressor imposed upon the body to produce an adaptive response. The extent of the adaptation is dependent upon balancing the severity of the stressor (intensity, frequency, and duration) with an adequate recovery interval. Exercise does not produce the adaptation directly. Rather, it serves as a stimulus for the body to produce the adaptive response.

McGuff (1997) has outlined this process in the following schematic:

Stimulus > Organism > X-days > Response 

In this model, the stimulus (exercise) is imposed upon the organism (human body), followed by a recovery period (x-days) in order to produce a response (increase in muscular strength and hypertrophy). Moreover, further questions arise from this model. What are the mechanisms of the stimulus? What effect does the stimulus have on the organism? What occurs during the recovery period (x-days)? How much recovery time is required? What happens if the recovery interval is interrupted? Does the recovery interval change with alterations in the stimulus or organism? What is the desired response?

Most of these questions can be answered by looking at existing physiology and medical research literature. A multitude of data is available concerning exercise stress and recovery. This presentation will review research on many aspects of the stimulus and recovery process of skeletal muscle in order to develop a biochemical adaptation model. When viewed together, this data supports the attached biochemical model (Fig 1) of the stimulus and growth process of skeletal muscle.

Following the model, it can be seen that the initial stimulus is a mechanical stressor to the muscle tissue caused by high-tension, low-velocity contractions, occurring during the eccentric (negative or lowering) phase of an exercise (Armstrong RB, Warren GL, Warren JA, 1991). The high-tension eccentric contractions cause disruption or micro-trauma of the myofilaments (contractile proteins), and cytoskeleton of the muscle fibers, usually in the largest fast glycolytic fibers (Friden J, Sjostrom M, Ekblom B, 1983). This initial mechanical damage is followed by an inflammatory response resulting in further protein turnover. Serum levels of creatine kinase are used as a measure of protein damage / turnover. Depending upon the severity of myofiber disruption, serum creatine kinase can increase to very high levels over the next five days, and not return to baseline for 10 or more days (Pedersen BK, Ostrowski K, Rohde T, Bruunsgaard H, 1998). This process must be left uninterrupted or protein synthesis and regeneration of the damaged fibers will not be complete. If an adequate recovery interval is allowed, the body will enter an anabolic state and the disrupted fibers will enhance their composition of contractile protein by increasing the number of myofibrils within the muscle fibers. The previously disrupted fibers will hypertrophy, increasing the resistance to further damage at similar intensities (Armstrong et al., 1991).

However, if another stimulus (workout) is introduced before recovery is complete, a cascade of negative biochemical reactions occurs in the body. Protein turnover will be incomplete, thus causing further disruption to previously damaged tissue. This imbalance between stimulus and recovery leads to an overstressed condition and an increase in the production of cortisol, a major catabolic hormone. An overabundance of cortisol upsets the balance between catabolism (breakdown of tissue) and anabolism (build-up of tissue), favoring the catabolic process (Urhausen A, Gabriel H, Kindermann W, 1995). If this occurs, the organism is now in a chronic state of degeneration called overtraining. Overtrained individuals experience a wide range of conditions, including: muscle soreness / stiffness, tendonitis, suppressed immune system, increased frequency of upper respiratory tract infections, depression, lethargy, weakness, reductions in testosterone, greatly reduced sperm count in men, depressed muscle glycogen reserves, insomnia, decreased exercise performance, and symptoms of Cushing’s disease (Budgett R, 1990; Fry RW, Morton AR, Keast D, 1991). Research indicates that chronically overtrained individuals may require up to three to six months to fully recover after cessation of training (Kuipers H, Keizer HA, 1988). At this point, further results from exercise are not possible.

Results from exercise are dependent upon the proper manipulation of stimulus and recovery. Research indicates that high intensity exercise may require an extended recovery interval. Further evidence shows that as the intensity of exercise increases, greater micro-trauma accumulates, requiring a greater recovery interval (Ploutz-Snyder LL, Tesch PA, Dudley GA, 1998). Details of the biochemical model and application to exercise prescription will be covered in the presentation and in report format at a later date.

Biochemical Model: Stimulus and Growth Process of Skeletal Muscle

Fig 1. Biochemical Model

Copyright 2003, Ryan A. Hall.

References:

Armstrong RB, Warren GL, Warren JA. Mechanisms of exercise-induced muscle fibre injury. Sports Med 1991 Sep;12(3):184-207.

Budgett R. Overtraining syndrome. Br J Sports Med 1990 Dec;24(4):231-236.

Friden J, Sjostrom M, Ekblom B. Myofibrillar damage following intense eccentric exercise in man. Int J Sports Med 1983 Aug;4(3):170-6.

Kuipers H, Keizer HA. Overtraining in elite athletes: Review and directions for the future. Sports Med 1988 Aug;6(2):79-92.

McGuff, D. The dose-response relationship of exercise. Ultimate Exercise: Bulletin Number 1, 1998.

Pedersen BK, Ostrowski K, Rohde T, Bruunsgaard H. The cytokine response to strenuous exercise. Can J Physiol Pharmacol 1998 May;76(5):505-11.

Ploutz-Snyder LL, Tesch PA, Dudley GA. Increased vulnerability to eccentric exercise-induced dysfunction and muscle injury after concentric training. Arch Phys Med Rehabil 1998 Jan;79(1):58-61.

Selye, Hans. Stress Without Distress. Signet, New York, 1974.

Had a great workout today. Nauseous, dizzy and my heart is pounding. Usually, I couldn’t care less what my heart rate (HR) is. It’s not that important. Resting HR is not an indication of one’s state of health, and HR elevation during exercise is a secondary consideration, and not something one should use as an indication of an effective workout. But, as hard as it’s beating, it’s certainly got my attention. My average resting HR is in the low 50’s, so the approximately 120 BPM I’m experiencing right now (roughly 5 minutes after my workout) is over twice normal.

I spoke with Arthur Jones regarding the subject this morning. He stated, and I agree, “six weeks of proper strength training can improve one’s cardiovascular fitness to a degree that is impossible with any number of years of aerobics.”

This reminds me of something Arthur said during an interview with Stephen Langer, MD on the show Medicine Man in the early 1980’s,

“…the lifting of weights is so much superior for the purpose of improving the cardiovascular condition of a human being that whatever is in second place is not even in the running, no pun intended. That is to say, running is a very poor, a very dangerous, a very slow, a very inefficient, a very nonproductive method for eventually producing a very limited, low order of cardiovascular benefit. Any, ANY, result that can be produced by any amount of running can be duplicated and surpassed by the proper use of weight lifting for cardiovascular benefits. Now I realize that there are hundreds of thousands, perhaps millions of people in this country who don’t understand that, who don’t believe that, who will not admit that. Now these people are simply uninformed. Certainly, it’s possible to run with no benefit, it’s possible to lift weights with no benefit. I’m talking about the proper use of weight lifting; and properly applied, weight lifting will improve your cardiovascular benefit to a degree that is impossible to attain with any amount of running.”

When properly performed, strength training meets all the requirements for cardiovascular conditioning. Assuming that one trains intensely enough and allows no rest between exercises, HR can be elevated to a tremendous degree and maintained throughout the workout. Some of the highest HR’s on record were achieved by subjects performing high intensity strength training during Nautilus Project: Total Conditioning at West Point Military Academy. Cadet’s maintained HR’s of 205-225 BPM for periods of 35 to 40 minutes during the workouts.

Your heart has no idea what you’re using your muscles for, whether it is running, cycling, swimming, strength training, etc. If the muscles are working harder, the cardiovascular system must also work harder to supply the working muscles with oxygen and remove the metabolic-by products of intense muscular work. Some supposed “experts” claim that for an activity to qualify as “aerobic,” or to be effective for cardiovascular conditioning, it must involve continuous, or “steady-state” work of the muscles in the lower body, such as is the case in running or cycling. This simply is not true. I can understand how they would come to this conclusion though. Since most people have much more muscle mass in their legs than in any other part of the body, it is easy to achieve a significant degree of HR elevation by performing only moderate intensity activity using those muscles. Most upper body exercises, however, do not involve enough muscle mass to place a significant demand on the cardiovascular system if only performed with a moderate degree of intensity.

The majority of these so-called “experts” have never properly performed a single set of high intensity exercise in their lives, much less an entire high intensity workout. And, if they strength train at all, they do so using such fast movements that meaningful muscular loading is almost entirely non-existent, and probably rest so long between exercises that any degree of HR elevation achieved quickly subsides. These people have no experience with real high intensity training, no idea what truly intense muscular work is, and no idea what kind of demand proper exercise places on the cardiovascular system.

It is not uncommon for endurance athletes, who typically consider themselves to be in superior cardiovascular condition and who have performed what they believed to be proper strength training in the past, to comment on how much of a demand high intensity strength training places on their cardiovascular system. Even marathon runners and triathletes, athletes that many consider to be the picture of cardiovascular fitness, have asked to be allowed to pause and rest in the middle of their workouts, claiming they needed to “catch their breath.”

As long as one is working some significant part of their body at a high degree of intensity, there will be a demand on the cardiovascular system, and as long as one does not allow a significant degree of rest between exercises, the HR will remain elevated for the duration of the workout. Properly performed, strength training does everything aerobics is supposed to do, more safely, more efficiently, and more effectively. Why destroy your musculoskeletal system for the sake of your cardiovascular system doing aerobics, when you can improve both with properly performed high intensity strength training?

This reminds me of something else Arthur said today, “…rather than be remembered as the man who saved America’s hearts, Cooper [Kenneth Cooper, MD, the “Father of Aerobics”] will more likely be remembered as the man who ruined America’s knees.”

A large percentage of the improvements in physical or athletic performance and physiological changes such as a decrease in resting heart rate (RHR) that many people assume to be caused by improvements in cardiovascular efficiency, are actually due to increases in muscular strength and endurance and improvements in metabolic conditioning.

There is no correlation between resting heart rate (RHR) and physical fitness. RHR alone is not an indication of one’s level of physical fitness. It is simply a clinical measurement, and must be considered within the context of various other factors. While a RHR in the low 40’s is often considered to be a sign of superior physical condition, within the context of other symptoms such as sweating, chills, abnormally low body temperature and a pale complexion it would be an indication of a serious medical emergency. However, a change in one’s average RHR may be an indication of an improvement or decrease in one’s level of fitness. A decrease in one’s RHR is usually attributed to an improvement in cardiovascular fitness, and is assumed to be an indication of an increase in stroke volume and ejection fraction. However, a decrease in RHR is more likely the result of an improvement in metabolic conditioning. It is not so much a matter of an increase in cardiac output as it is an improvement in the muscles’ ability to utilize what’s being sent to them, which decreases the demand placed on the heart, both at rest and during intense physical activity. Not to mention the degree to which cardiac output can be increased is very limited, and very quickly achieved by proper training. Past a certain point, increases in the size of myocardia would begin to actually decrease the volume of the left ventricle and obstruct outflow through the aorta, which would decrease cardiac output. This is common in athletes who abuse cocaine.

Improvements in metabolic condition probably contribute much more to decreases in RHR and in HR elevation during intense physical activity than increases in cardiac output. Such metabolic conditioning can be achieved through proper strength training. It’s the muscles ability to use what’s being sent to them, more than the heart’s ability to send it that’s important.

What amazes me is that despite the fact the Surgeon General has basically stated any activity slightly more demanding than watching TV when performed regularly will help improve and maintain cardiovascular fitness, there are people who will say that high intensity strength training, which may be the most brutally demanding form of physical activity ever devised, will do nothing for the heart. That this is nonsense should go without saying. And, if all that is necessary for cardiovascular fitness is going for a short walk or working in the yard, or performing some other light activity for a few minutes every day, then why do hundreds of thousands of people insist on destroying their joints and spines by jogging? Because they believe it will help them lose fat? More nonsense.

Aerobics does not burn enough calories to be worth performing for that purpose. If a person does something for the sole purpose of burning calories, their time is not worth much. A 150-pound man running at a 7mph pace will burn, at most, about 8 kcals per minute, or 480 calories per hour. He would probably burn about 100 of those kcals if he sat and did nothing for an hour, so the actual extra kcals expended as a result of the activity would amount to only 400 or so. If he did this every night for a week, he wouldn’t burn enough calories to equal the amount stored in one pound of fat. Such a high volume and frequency of running probably would cause a significant loss of muscle though. Since a muscle yields only 600 kcals, compared to the 3,500 kcals in a pound of fat, it would be possible to lose over 4 pounds of week in such a manner if one was losing muscle weight. Note that most habitual joggers, marathon and ultra-distance runners, and other obsessive/compulsive aerobics addicts often have the sickly skeletal appearance of Nazi death-camp refugees and AIDS victims. This is hardly a healthy appearance.

The only effective way to create a negative net-calorie balance is to follow a reduced calorie diet. It’s much easier and far more time efficient to simply eat less, than to spend hours a day, several days a week pounding your joints on the pavement or slaving away on some oversized hamster-wheel. And when you’re not wasting hours a week on the stepper or treadmill, you’re going to get much better results from your strength training. If one truly desires to increase their caloric expenditure, then it is strength training they should focus on.

Aerobics only burns calories while you’re doing it, and damn few at that. Some people will point out that the metabolism is also elevated for several hours afterwards, but this increase is negligible, and hardly worth it. Aerobics can cause you to burn fewer calories the rest of the time though, since when taken too far it can cause a loss of muscle, and can prevent your body from producing the increases in muscular strength and size stimulated during strength training.

Strength training, on the other hand, increases the amount of calories your body burns all the time, 24 hours a day, 7 days a week. Every pound of muscle added to the body of an adult human increases caloric expenditure by an average of 30 calories per day. If one gains only 5 pounds of muscle, which most previously untrained subjects can achieve in a matter of weeks, one’s average daily caloric expenditure is increased by 150, for an increase in weekly caloric expenditure of 1,050, the amount of calories in one third of a pound of body fat.

More importantly though, proper strength training is necessary to ensure discriminate weight loss while dieting.

If one diets, or does aerobics, or both, but does no strength training, the weight lost will come from a combination of fat, muscle, and organ tissue. Muscle is a very highly metabolically active tissue, and when your body perceives a reduction in caloric intake, it’s going to try to adapt by reducing its caloric expenditure. One of the most effective means of accomplishing this is to decrease the amount of metabolically expensive tissue, one of the most expensive being muscle. Strength training is necessary to ensure that the body maintains, and hopefully increases muscle mass while fat is lost.

And no, combining aerobics and strength training won’t produce better results. Adding aerobics usually makes things worse. It can prevent much of the improvements stimulated by the strength training workouts, and keep you chronically fatigued and hungry. Research by Westcott and Darden has demonstrated strength training and diet produce greater improvements in body composition when not performed in conjunction with aerobics.

So what is a moderately reduced calorie diet? Just that, a moderate reduction in caloric intake. There are several ways to determine the amount of calories one should consume while trying to lose fat. Mike Mentzer recommends recording your average daily caloric intake over a period of 5 days to and comparing it to changes in bodyweight to estimate average daily caloric expenditure. If your weight stays the same, your intake equals your expenditure, if you lose, your intake is less than your expenditure, if you gain, your intake exceeds your expenditure. Once you determine your average daily caloric expenditure, subtracting 500 from this amount will give you the number of calories you must consume in a day to produce a rate of fat loss of approximately one pound per week.

Another means of estimating caloric intake for fat loss is to multiply your lean body mass in pounds by 10, (absolute minimal number being 1,000) and then adding 200 to this number. The result is your daily caloric intake for the first two weeks of a six-week dieting cycle. During weeks 3 and 4 you would consume 100 less calories per day, and during weeks 5 and 6, 200 less calories per day. If after the end of the six weeks you have more fat to lose, repeat the cycle.

For example:

A 140-pound woman, with 25% body fat would have 35 pounds of fat and 105 pounds of lean tissue. 105 multiplied by 10 would give us a minimal average daily caloric intake of 1050 calories. Her 6-week cycle would be as follows:

Weeks 1-2: 1,250 cals/day
Weeks 3-4: 1,150 cals/day
Weeks 5-6: 1,050 cals/day

A 250-pound man, with 25% body fat would have 62.5 pounds of fat and 187.5 pounds of lean tissue. 187.5 multiplied by 10 would give us a minimal average daily caloric intake of 1875 calories. His 6-week cycle would be as follows:

Weeks 1-2: 2,075 cals/day
Weeks 3-4: 1,975 cals/day
Weeks 5-6: 1,875 cals/day

Once you achieve the degree of leanness you want, simply gradually increase your average daily caloric intake by 100 kcals every week until you stop losing fat to determine your maintenance level. Realize that even though total caloric intake is reduced while on a diet, your average daily protein intake in grams should remain the same. The reduction in calories should come from carbohydrate and fat intake.

Aerobics is simply not necessary for fat loss and makes no meaningful contribution to a fat loss program. I’ve supervised enough diet programs, and trained enough people who’s goal was weight loss to state with absolute certainty that one can dramatically improve their body composition in a matter of weeks with a proper diet and strength training program alone. Ellington Darden, PhD has issued a challenge to anyone to produce documentation (measurements and standardized before/after photographs) of better results from a fat loss program than those he has produced during his research for his diet and exercise books, and so far, nobody has produced anything even close.