by E. Paul Zehr
Since I have you on a flashback to concussion, let’s begin there. The repeated effect of concussion can lead to later issues of cognitive impairment including dementia. Without a doubt many people have observed these kinds of effects since ancient times. However, this issue was brought up explicitly in the modern scientific world in 1928 by Harrison Martland (1883–1954), who described a certain neurological syndrome in a boxer that is known as being “punch drunk.” The terms “dementia pugilistica” and “punch drunk” refer to appearing to be drunk when no alcohol is involved. Slurred speech, problems in maintaining balance, and generally uncoordinated arm and leg movements are common. Clearly, repeated blows to the head can lead to persistent effects on movement control and cognition. The explicit question I want to address here, though, is whether or not repeated head injury might predispose someone to degenerative diseases—such as Alzheimer’s—that affect memory and cognition.
Alzheimer’s disease has been described as the most prevalent of all degenerative diseases of the nervous system, affecting an estimated 25 million people worldwide in 2007. At the beginning of the twentieth century, German physician Alois Alzheimer (1864–1915) observed an interesting patient (coincidentally known by the initials “AD”) who had experienced memory loss and dementia in her late forties. She became the first person diagnosed with Alzheimer’s disease. Since that time we have learned that someone with Alzheimer’s shows a continual deterioration in memory and functional ability such that activities of daily living eventually become impossible. When individuals with Alzheimer’s disease are autopsied and their brain tissue is examined under a light microscope, hardened plaques are found that are formed from proteins called beta amyloid. The body makes amyloid and beta-amyloid proteins as a matter of course. In a healthy brain, the beta version would be broken down and gotten rid of. It is believed in people with Alzheimer’s disease these proteins harden and form plaques. The plaque formation process precedes actual memory loss and dementia by many years. Similar to this, a healthy brain has a protein called tau that forms little structures called microtubules. In Alzheimer’s disease, this protein has an abnormal form and results in neurofibrillary tangles. Together the plaques and neurofibrillary tangles degrade the brains neurons and are seen clearly at autopsy. The disease itself is not amenable to treatment. Genetic factors likely play a strong role in the expression of Alzheimer’s. One gene in particular, called apolipo-protein E, or APOE for short, is a repeatedly confirmed suspect.
We don’t know whether Batman is genetically predisposed to get Alzheimer’s. What we want to know is whether his repeated head trauma may lead to a greater chance of his getting the disease. We discussed back in Chapter 13 that head trauma resulting in loss of consciousness and concussion was due to rotational accelerations, or rapid forward momentum of the brain. There were effects of this acceleration not only on a person’s metabolism but also on his or her brain tissue. The idea has been floated that repeated concussion could help increase the likelihood of formation of amyloid plaques and neurofibrillary tangles.
Unfortunately, it is not possible to get full diagnosis and confirmation of diagnosis of Alzheimer’s until autopsy, and you cannot easily follow someone who is repeatedly concussed in sports such as football or boxing until their demise and then check for the autopsy confirmation. Instead, researchers have tried to look for associations between the kinds of symptoms shown by people with Alzheimer’s and those shown by people who display punch-drunk-type syndromes. Recent work, including that by Kevin Guskiewicz and colleagues from the University of North Carolina at Chapel Hill, shows a strong relation between dementia and repeated concussion in professional football players. Retired football players who developed dementia and Alzheimer’s-like symptoms did so at much younger ages than did the general population.
Other researchers have also shown that the risk for Alzheimer’s is higher if the concussion syndrome is worsened by repeated concussion and if there is a family risk factor for Alzheimer’s. It may be that the repeated concussive incidents may increase the production of the beta amyloid protein thus leading to the plaque formation that interferes with normal brain function. This represents an unfortunate but understandable homeostatic response of the brain to the mechanical stresses of repeated injury. What we would conclude for Batman is that he is at significantly higher risk of developing Alzheimer’s. Fortunately he will have at hand a suitable caregiver in the form of his brother Bob, who, because he shunned the extreme lifestyle of his driven brother Bruce, would only have a normal risk of Alzheimer’s.
There is also evidence that repeated head trauma can lead to neurofibrillary tangles without the plaques seen in Alzheimer’s. These can be found in areas of the brain that are key to motor coordination, such as the cerebellum and basal ganglia (recall those motor control advisors from Chapter 7), and memory, such as the hippocampus. This has been described as a “pugilistic Parkinson’s,” because it presents in a similar fashion to that seen in Parkinson’s disease. Although it is yet unknown whether this is actually the case, it is possible that this kind of background could explain some of the Parkinsonian symptoms that some boxers—notably Muhammad Ali—display years after all boxing activity has stopped.
Physiology and Motor Performance
An important aspect working against our ability to perform at a high functional level as we age is sarcopenia. This term, coming from Greek for “lacking of flesh,” refers to the normal lessening of strength that occurs in aging. Along with the loss of muscle mass may be increased porosity of bone (osteoporosis) and weakened bone (osteopenia). The graph shown in Figure 15.2 is meant to illustrate that from about age 30 there is a steady decline in physiological function. Shown on the figure are speed of nerve conduction in the nervous system, function of the heart and lungs, and overall ability to perform work. Kidney function and other organ systems also deteriorate. As for the loss of muscle, a lot of the normal regulation of muscle mass takes us back to Chapter 3 when we first met the insulin-like growth factors (or IGFs). Reduction in IGF levels as we age may remove a potent stimulus for maintaining muscle mass.
Let’s look at what happens to our bodies as we age. More specifically let’s look at what happens as we move beyond about age 30 and our physiological function begins to decline. I am going to concentrate this discussion on the motor system and our ability to activate our muscles. It is not my intention—and it would require many more pages to do so—to list all the physiological changes that occurin aging.
Figure 15.2. Decline of function in the nervous and cardiovascular systems linked with a decline in overall functional capacity at various ages for Batman. Data from Hertoghe (2005).
Think back to the motor unit, which we defined in Chapter 4 as a motoneuron, in the spinal cord and all the muscle fibers that it energizes. Don’t be shocked, but as we age, our motoneurons die. Given our discussion above about the Hayflick limit, this shouldn’t be too surprising. If the cells that relay the command for muscle to become active die, you might suppose that factors like muscle strength would decline. And clearly, that is true. As much as 50% of skeletal muscle mass may be lost between the ages of 20 and 90 years, and there is a corresponding reduction in muscle strength.
There is also death of muscle fibers, particularly those found in the fastest contracting motor units, the Type IIa group. Usually you don’t really notice the extent of the decline in motoneuron number or muscle fibers that much. This is because your nervous system is exceptionally good at covering up for these changes. This is another way of saying that changes in the connections within the nervous system compensate for the age-related death of muscle fibers and motoneurons.
Imagine a muscle in your leg that may contain 250 motor units. In a large leg muscle, each motor unit might have a thousand muscle fibers in it. This relationship of motor cells to motorneurons is called the innervation ratio; in this example it would be a thousand fibers per motorneuron. Innervation (and this is scientists being really c
lever with naming again!) means bringing nerves to something.
Well, the number of motor units in that same muscle might drop to 125 by age 70. This means you would have lost 125 motoneurons. However, many of the muscle fibers would still be sitting in your muscle waiting to become active on command. You may have lost 50% of the motoneurons but only 10% of the muscle fibers. Shouldn’t this make you half as strong? Not necessarily because the other motoneurons innervating muscle fibers in that leg muscle can send branches from their axons over to the muscle fibers that are just sitting there waiting. This is called “sprouting” and eventually leads to much larger innervation ratios—in this example, let’s says it is now 1,500 fibers per neuron—that lead to a preservation of strength. By the way, this is the same process that occurs in recovery from some nerve injuries.
Batman’s nervous system also would show a general slowing with aging. There is a reduced speed of conduction within the nervous system. The events involved in muscle contraction are also themselves slowed down. Despite these declines that occur in everyone’s nervous system with aging, an active lifestyle—such as Batman certainly lives—can help offset the overall impact of these changes. The main reason for this goes back to the general stimulus-response model we have been using all along. If there is a maintained exercise stress across the life span, there will be a corresponding attempt to respond to minimize the effect of the stress. This means maintaining muscle mass as best as possible and maintaining needed coordination and motor skills.
Hormone levels also decline over the life span. As an adjunct to physical activity, in certain cases hormone and steroid replacement therapies can also be helpful. These are usually used only in severe cases. However, restoring hormone levels, and in particular those related to muscle mass such as the IGFs we talked about in Chapter 3, has been used extensively to help improve physical capacity with aging.
In addition to experiencing reduced muscle mass, Batman could have a problem with decreased bone-mineral density. Because of his nocturnal lifestyle he doesn’t get much sun, which is a major source of vitamin D. When Batman is out and about during the day he wears the batsuit, and his skin doesn’t see much light. Even as Bruce Wayne, he is mostly at business meetings inside buildings. So, his vitamin D intake from sun exposure is very low. Vitamin D, as we learned in Chapter 5, is a major regulator of bone mineralization.
So, Batman is at increased risk for osteoporosis! This risk will of course be offset by the helpful bone stimulus of being so active. Still, he ought to drink lots of vitamin D–enriched milk products and take his vitamins.
Codger or Not?
The last point to address here speaks to the chapter’s subtitle—will the Caped Crusader become the caped codger? Clearly the answer is yes. However, the implied question is really when will Batman have to hang up the old cape? To consider this let’s discuss some examples from sports that encompass the elements of physical power and toughness and that have physical contact as main elements: NHL ice hockey and professional boxing. We will take these real-life activities as examples that emulate the physical pounding that Batman would take in his career as a costumed crimefighter.
To give us a benchmark for how long someone could continue in a physically demanding job like being Batman, let’s look specifically at the careers of NHL great Gordie Howe and former heavyweight boxing champion George Foreman. They both represent athletes who performed at a high level at a time when many other professionals would be off making commercials or providing commentary on sports broadcasts.
Gordie Howe—a.k.a. “Mr. Hockey”—was born on March 31, 1928. Howe debuted in the NHL for the Detroit Red Wings in 1946 at the age of 18. He is best known for the length of his playing career, the high level of his play, and the physical nature of his game. In fact, the term “Howe hat trick” has often been used to describe a game in which a player gets a goal, an assist, and wins a fight. During his 25-year career with Detroit, Howe won four Stanley Cup championships as well as the scoring championship and most valuable player trophy. He is third in NHL all-time scoring with 1,850 points. This includes 801 goals and 1,049 assists. Including all of his goals from his entire professional playing career (NHL and World Hockey Association [WHA]) puts Howe first in goals with an incredible 975. The point is that Gordie Howe was one of the best players in hockey history. He retired (first retirement) in 1972 at the age of 43. In his last NHL season for the Red Wings he scored 23 goals and added 29 assists for 52 points in 63 games. This would have to be considered outstanding for almost any age but is staggering for a man in his early 40s.
But there is more. He came out of retirement for the 1973–1974 season to play in the WHA with the Houston Whalers and then the New England Whalers. It is amazing that during his six seasons in the WHA, Howe had two years with more than a hundred points. Then, the most impressive feat, in my view, was in 1979–1980 when Howe played in the NHL again for the Hartford Whalers. He played in all 80 games and scored 15 goals and 26 assists at the age of 52! This is a truly amazing performance and shows that well into what many would consider the early retirement years, it is possible to produce at a high level.
The boxing career of George Foreman represents another example of performance over a long span. He was born on January 10, 1949, and won the 1968 Gold Medal for heavyweight boxing at the Mexico City Olympics. Thereafter he turned professional and won the undisputed world heavyweight championship in January 1973 by knockout over Joe Frazier. George had many memorable fights in his career, including the “Rumble in the Jungle” in which he lost to Muhammad Ali. However, of relevance to aging and performance is that Foreman had several retirements and comebacks over the years. Notably, in November of 1994 he defeated Michael Moorer by knockout to win the heavyweight title. This victory was at the age of 45, and in so doing Foreman became the oldest fighter to win the heavyweight title championship. His last fight was some years later at the “tender” age of 48. This example of George Foreman shows that even pure fighting prowess can be maintained in championship form into the fifth decade of life. Also, although he never won the heavyweight crown, the Canadian boxer George Chuvalo had a 23-year career that begin in 1956 and ended in 1979 at the age of 42. Over that time he fought 93 times, amassing 73 wins—including 64 by knockout—and 18 losses. He fought Muhammad Ali twice and went the distance but lost by decision both times. Chuvalo really does represent high-level performance for a long career.
So, how long can Batman function as Batman? Well, based on the evidence at hand I would say Batman could still operate at a high level into his early 50s. He will have lost a bit of speed, endurance, and pure physiological power as we discussed above. Despite not being able to do everything quite the way he used to, he could still achieve most of his objectives.
Also, his technical competence will help compensate for many of the gross physiological losses. I have found in my own martial arts training that when I face many “older” karate masters—those in their late 60s up to late 70s—it is not how fast you move but when you move that is important. They still seem very adept at throwing me to the ground. Let’s conclude that Batman could still be Batman into his sixth decade but that he should then retire and take up his rocking chair at stately Wayne Manor. Also, in his later years he will need to rely more and more on his acolytes Robin, Batgirl, Night-wing, and whoever else he can train.
As we shall see in the next chapter, we need to make a distinction between the possibility of being able to perform at a high level as we age and the ability to remain at the peak of our performance. Don’t you want to know how long Batman can really be at his peak to remain the undisputed guardian of Gotham?
CHAPTER 16
The Reign of the Bat
CAN YOU REALLY BECOME BATMAN
AND REMAIN BATMAN?
The main rule of thumb when doing Batman is, “Is it realistic or not?” That is more important than anything else.
—From an interview with Kia Asamiya, author of Batman: Child
of Dreams (2003)
We have explored many aspects of training and what happens to the human body as a result of training stresses. Everything we have discussed is embedded in the concepts of stress and homeostasis. We have talked about some biology, some biomechanics, and some injuries. All of this was meant to illustrate what would have happened to the fictitious Bruce Wayne or to a real person who undertook to become Batman. I have also included many quotes and comments from artists, writers, and editors for the Batman comics who all expressed the idea that an inherent part of the Batman mythology was that he wasn’t a person with superhero powers. Batman is just a human being who trained himself to the ultimate extent. This general idea is shown in Figure 16.1 in a thumbnail sketch of the progression from Bruce to The Bat-Man to Batman differentiations that we have followed throughout the book.
Figure 16.1. Transformation of Bruce Wayne to Batman shown in a parallel scale for physiological adaptations occurring in his body.
After having read through all this material, let’s reflect briefly on whether you could become Batman if you wanted to. If so, for how long could you remain as Batman?
The short answer is that, yes, in my view and in light of everything I have outlined for you, a person could become Batman (notice I said a person, not necessarily you or I). This person would need to have the proper blend of genetic endowment, be driven at a fanatical level by some passionate goal, and have inordinate amounts of time and money to undertake all the extreme privations and training needed. Following the general stimulus-response model of maintaining homeostasis by altering biological function we have talked about all along, yes, you could bring about the necessary training adaptations to do so. If all that were in place, then, yes, you could become Batman.