Becoming Batman

by E. Paul Zehr

  This measure of expired gasses makes use of equipment called a “metabolic cart” and requires the person to wear a mask or two-way valve device (called a Rudolph valve) that is essentially the reverse of a scuba regulator. In a scuba regulator the intake is from a pressurized gas cylinder (the scuba tank), and the outlet is simply to the surrounding water. In a standard Rudolph valve setup, the intake is simply the ambient air and the outlet is to a gas analysis system. Such a setup is shown in Figure 6.6 from an older experiment that I did to find out the metabolic cost of performing martial arts techniques.

  By comparing the percentage concentration of oxygen and carbon dioxide in the room air and in the expired gas, we calculated the amount of oxygen consumed and carbon dioxide produced during very vigorous karate movements simulating fighting. By the way, during these kinds of activities, energy use can be as high as 90% of the level used pedaling a bicycle at maximum speed for ten minutes! Obviously, Batman doesn’t fight people for ten minutes, but the point is that the peak of the energy used can be very high.

  Before the arrival of modern metabolic carts and portable measurement systems, a simple reversal of scuba was used for gas collection. Created in 1911 by British physiologist C. G. Douglas, this technique involved collecting all the expired gas in a big sealed canvas bag. Given the hugely creative talent scientists display in generating colorful names, you won’t be surprised to learn this was called a “Douglas bag.” The Douglas bag technique was originally developed to help gauge respiratory and cardiovascular fitness in advance of the 1911 joint U.S.-U.K. Pike’s Peak expedition. It was subsequently used in hundreds of studies and was crucial for advances in understanding of the metabolic cost of many tasks.

  Using indirect calorimetry we know that for the consumption of every liter (or about a quart) of oxygen approximately 5 kcal of energy are used. This allows the calculation of the basal metabolic rate (BMR), which is the minimum metabolic rate needed just to maintain your body’s basic functions. The overall daily metabolic rate consists of three—here we are with the threes again!—main components: the BMR, the amount of energy related to activity, and the amount related to food and eating. For the general person, the BMR accounts for 60–70%, activity 15–50%, and feeding 10% of the total daily metabolism. Many factors can affect the BMR including genetics, age, gender, amount of lean tissue, diet, hormones, and activity level. The BMR can be roughly estimated for men as 1.0 kcal/hr/kg body weight. For women, the value is slightly lower at 0.9 kcal/hr/kg body weight. As such, the BMR for Bruce Wayne/Batman is about 2,400 kcal. Now, added to that is the effect of activity, which for Batman can be up to 50% of his total. By the way, metabolic activity varies in different animals and adheres roughly to a principle called “allometric scaling.” The simple point is that basal metabolic rate increases with mass. Despite that, the very low-mass bat has a very high metabolic rate. In fact bats have a metabolic rate that is among the highest in the animal kingdom and is just behind the hummingbird!

  Figure 6.6. A Rudolph valve measures the amount of oxygen and energy used to perform karate by calculating the oxygen taken in and the carbon dioxide produced.

  The amount of energy expended in activity can be expressed in units of calories, just as with food consumption. Daily energy expenditures vary widely among people and activities. Cyclists in the famous Tour de France may use up to 5,000 calories on fairly flat stages and up to 8,000 calories a day on the mountain climbs. Assuming that Batman isn’t gaining or losing weight, and given Batman’s activities, he probably tops out about 3,500 to 4,000 calories daily. His brother Bob sits at around 2,800 calories. What we really want to know is a more tangible estimate of how much energy Batman expends while actually being Batman.

  To give you some indication and frame of reference for this, I watched the 2005 Warner Bros. movie Batman Begins and kept track of the activities of Batman and Bruce Wayne. I categorized and timed the main Batman activities as fighting (approximately 18 minutes), climbing (approximately 6 minutes), driving (approximately 6 minutes), swimming (about 1½ minutes), and calisthenics, hiking, and his machine work to build his gear (about a minute each). I did all that so we could compare how many calories of energy Batman/Bruce used during the roughly 130 minutes of the movie. Calculating the energy requirement during these special categories yielded about 520 calories over the 30-some minutes of Batman activities. Bruce spent about 315 calories over the remaining 99 minutes of the movie, which gives us a total of around 835 calories. You can compare that with the number of calories expended simply while sitting there watching the movie itself. For men with body weights between 74 and 83 kilograms (165 and 185 pounds), these values would be 170–190 calories, and for women between 58.5 and 72 kilograms (130 and 160 pounds) the values are 130–160 calories. Batman expended a lot more than you or I would have just watching the movie!

  We started off part of this discussion with the concept of having a high or low metabolism. Well, how much can a person’s metabolic rate change with training? A way to look at this is to consider what a sustainable metabolic rate is. Given the principles underlying homeostasis, your body tries really hard to maintain an energy budget that keeps body mass constant. This means that energy intake will equal energy expenditure. We already discussed how the BMR is a main contributor to energy expenditure and how exercise and work can dramatically affect metabolic rate when we are exercising.

  What is the long-term effect of activity on metabolic rate? Many studies suggest there are definite limits to maximal metabolism. That means we cannot just do more and more on an ever-increasing scale. Sustainable energy expenditures are based upon the physical activity level and can be as high as two and a half times the BMR. When someone begins an exercise program—like when Bruce Wayne began to train to become Batman—the physical activity level goes up. For example, if an untrained person, such as Bob Wayne, began a training program—finally, after all these years—for a half marathon, his physical activity levels could increase from about 1.7 (completely sedentary is 1.5; this number is not zero because of the energy involved in just being alive) to 2 after eight weeks. In highly trained and highly active people, like soldiers during field training, this can get as high as 2.4. However, body mass losses will often occur and can be as much as five pounds per week. This would be the likely result of acting as Batman. Those Tour de France cyclists can get as high as 3.5 to 5.5 times the basal physical activity level but there will be body composition changes. The use of supplementary high carbohydrate foods and drinks like Gatorade help reduce these negative effects. These athletes also tend to eat many small meals throughout the day. High performance athletes seem to be able to maintain their the basal physical activity level at much higher levels probably because of those genetic factors we talked about earlier.

  As far as adaptations to training are concerned, the changes all happen in systems that drive the metabolic pathways themselves. Aerobic exercise leads to an increase in mitochondria, which in turn helps with aerobic metabolism. Anaerobic activity leads to increased enzyme activity in the glycolytic pathways and an increase in storage of ATP-CP. This all follows very logically in the stress-response framework I have used elsewhere in the book. Batman’s body experiences a stress (such as exercise) and responds with a compensation to minimize that stress. It all seems so simple that it is easy to forget about the effort needed to provide the stress in the first place!

  Don’t Be Nervous About Metabolism

  As with almost every function, Batman’s nervous system is intimately involved in regulating food intake, digestion, and metabolism. There are two general kinds of “tone” for the nervous system control of metabolism, both of which work together but in antagonistic ways, a feature of homeostatic control, of course! During the fed state (discussed earlier in the chapter) there is dominance of what is called “parasympathetic tone” related to insulin release. This is a state of “wine, dine, recline” where the idea of relaxation and low stress is captured. In contrast, t
he opposite tone is called “sympathetic;” it reflects high stress “fight or flight” and stops insulin release.

  To sum up, metabolic activity is fundamental to biological function. Put another way, no metabolism equals no life at all for dear Batman. Biological function is intimately regulated by homeostatic control mechanisms, as you might have guessed. It is therefore to be expected that we humans have some pretty cool control over endocrine function of metabolism. As you recall, metabolic rate is related to glucose levels in the blood. It may surprise you to know that hormones we met in Chapter 3—cortisol, catecholamines, thyroid hormone, and growth hormone—are all involved in this process. As a point of trivia, thyroid hormones are catabolic in adults like Batman but are actually anabolic in children. This makes sense if you think about it, as children are still growing (building up). So when Robin as Dick Grayson first met up with Batman their endocrine response was opposite for this particular function!

  An Internal Battle Besieges the Batbody

  By reading through the last few chapters and this one, you have really had a good look at what is going on within Batman’s body. Are you wondering how much is too much, though? How much change can he really undergo, and do all the changes get along with each other without causing damage to the body? I explained that power, strength, and endurance occur separately, but obviously even in your own activities of daily living you wind up doing things that combine the needs of all three. Well, Batman needs to be really good at all these things. Can he be the best at everything, though? Can he be the strongest, fastest, and go the longest?

  The short answer is “no,” and there is a relatively simple explanation. If you keep in mind the general principle of adaptation to stress that permeates this book, you will probably realize that the kind of stresses that result from trying to be the strongest (and needing very brief but maximal muscle activity) are quite different from those that result from trying to go the longest (and needing low-level muscle activity repeated over and over again for long periods). Because of this we say there is conflict between adaptations for endurance and power. There is a reason why NASCAR drivers aren’t out there driving their pickup trucks! The pickup truck is the wrong tool for the job. Similarly, the metabolic adaptations arising from the different metabolic stresses are trying to create two different kinds of tools.

  A better example is thinking of track and field. You find runners who do, say, the 200- and 400-meter races. These races require mostly power and short duration activity. You don’t find any runners who compete in the 200-meter and in the 10-kilometer or marathon. The physical look of the runners—reflecting the body composition needed for success in those different races—is quite different as well. Within a framework of stress and strain and challenges to homeostasis, it is not possible to maximize adaptations to all responses! A good training program—and certainly one Batman would have followed—includes strength and endurance training. You can do them together; you just cannot expect to push the adaptations in a maximal direction for both.

  In the next chapter, we will look at how Bruce Wayne put his muscle, bone, metabolism, and hormones to work together and began training his body in the movements needed to be one of the world’s best crimefighters.

  PART III.

  TRAINING THE BATBRAIN

  Batman on the path to mastery

  of the martial arts

  CHAPTER 7

  From Bruce Wayne to Bruce Lee

  MASTERING MARTIAL MOVES

  IN THE BATCAVE

  Experience teaches slowly, Robin. And at a cost of many mistakes.

  —Adam West as Batman, from the ABC TV series Batman

  Rare because it is one of the few times that Batman has come close to losing control. Revealing because it shows the awesome physical strength of an unleashed Dark Knight.

  —Tales of the Dark Knight: Batman’s First Fifty Years: 1939–1989 by Mark Cotta Vaz

  Batman seems to have an extensive repertoire of movement at his fingertips. So in becoming Batman, Bruce Wayne had to learn all the movements for some pretty complex skills. This means quite a bit of plasticity, or flexibility, must have been going on in his brain. He had to learn a lot and his body had to accept that learning and demonstrate it as skill at martial arts. You might watch a Batman movie or read a comic and say he has good reflexes. In this chapter we look into this concept of reflexes and what it means to learn a skill so well that it seems you can do things automatically and almost on “auto-pilot.”

  Figure 7.1. Seamless relationship in the nervous system between the brain, the spinal cord, and feedback from the moving limbs.

  Before we learn about learning and fine-tuning movements, we need first to discuss the basic way our movements are controlled. This means reviewing the different parts of the nervous system and their roles in movement or motor control. Movement is a basic characteristic shared by all animals, including us humans. Sir Charles S. Sherrington wrote in 1924 that “to move is all mankind can do . . . whether in whispering a syllable or in felling a forest.”

  The nervous system controls muscle activity and subsequent movement. It does so by means of a three-part system composed of the brain, the spinal cord, and sensory feedback. This system is illustrated in Figure 7.1, where the three parts are shown endlessly interacting with each other. In this system, commands within the brain and spinal cord interact and are shaped by sensation generated by movement itself. We are going to discuss these bits separately, simply as a convenient way to describe the flow of information. Certainly, all these parts are intimately linked and communicate during real movement. However, we can separate them to lay down some basic concepts.

  The Cortex Is in Charge

  Let’s begin, as we did back in Chapter 4 when talking about the activation of muscle, by starting in the brain. Keeping on with this idea of three-part systems, we are going to talk about three sections of the brain: the cerebral cortex, the cerebellum, and the basal ganglia. The relationship between these parts is shown in Figure 7.2.

  These three parts interact on many levels, but probably the easiest way to think about them is to picture the nervous system as a kind of huge company with the cerebral cortex as the CEO of motor control. In fact, let’s make the cortex the president and CEO. Following on from this, the cerebellum and basal ganglia are vice presidents of movement planning and execution. The spinal cord circuitry represents the local district managers who oversee implementation of plans from head office—and some plans of their own. Feedback arising from movement represents information from actual agents in the field. The main point is that the VPs get to give lots of advice to the president, who has an “open door” policy with his advisors. However, the president gets to make his own choice on matters of strategy and output related to movement and doesn’t have to listen to the advice he is given. The general idea is that we have the cerebral cortex coming up with a plan of movement based upon advice from loops in the basal ganglia and cerebellum.

  Figure 7.2. A corporation compared to the nervous system.

  Let’s consider some details in the cerebral cortex. Most brain regions are organized with relation to the main function that occurs in that part of the brain. Think back to the motor cortex, which I described earlier as the place where the final motor output cells in the brain are found. This area is highly or ga nized and even holds a loose representation of the map or plan of the body (remember Chapter 4 and what Penfield called the little man, or “homunculus”).

  I want to switch analogies at this point and bring up the concept of upstream and downstream. When we trace the action in the body from where the thought to move occurs and the action of movement takes place, those actions farther from specific movements can be referred to as upstream. In the case of our corporation, the VPs are upstream from the agents in the field and the CEO is even farther upstream.

  Now that we have defined our terms, let’s address where plans to move arise and what they mean. To do so requires thinking about two oth
er parts of the cerebral cortex: the supplementary motor and premotor areas. The main thing about these two areas is that they are anatomically close to the primary motor cortex but are a bit upstream from the final motor commands that issue from the motor cortex to activate muscle. Activating the motor cortex uses that mini-map of the body’s muscles and is related to a clear, single muscle representation. Stimulation of the supplementary motor area produces activity instead in groups of muscles. Let’s say we were to stimulate Batman’s cerebral cortex (or really Bruce Wayne’s brain, as we would need that mask and cowl out of the way!). If we were right over the part of the motor cortex for the hand muscles, we could evoke small twitch movements of just, for example, the index finger. However, if we stimulated the supplementary area, we would get activity of many related muscles. We might find Batman’s index finger curling along with flexion of his wrist and bending of his elbow. So, motor activity still results after activation of the supplementary motor area, it is just more complex than that from the motor cortex.

  There are two additional things about the supplementary motor cortex that are worth commenting on. This part of the brain, being related to planning, shows lots of activity when movements are imagined but not performed. For example, if Batman were thinking about, or rehearsing, certain movements but not actually doing them, his supplementary motor area would be active but his primary motor cortex would not. That is because if his primary motor cortex were active, he would actually be doing the movement! If you tap your right index finger against this page while you read it, both your motor cortex and your supplementary motor area for your right finger flexor muscles (found on the left side of your brain) will be active. If instead you just think about tapping your finger but don’t actually do it, only the supplementary motor area will become active.