What if aging were programmed into our genetic code? This possibility seems more likely as the explosion of knowledge about human genetics con­tinues to unlock the secrets of our genetic code. Even when cell death appears random, researchers believe that such losses may be part of a master genetic program that underlies the aging process (Pankow & Solotoroff, 2007). Programmed cell death appears to be a function of physiological processes, the innate ability of cells to self-destruct, and the ability of dying cells to trigger key processes in other cells. At present, we do not know how this self-destruct program is activated, nor do we under­stand how it works. Nevertheless, there is increasing evidence that many diseases associated with aging (such as Alzheimer’s disease) have genetic aspects.

It is possible that the other explanations we have considered in this section and the changes we examine throughout this text are the result of a genetic program. For example, there is evi­dence that osteoporosis (Riancho, Zarrabeitia, & Macias, 2008), changes in brain cells (Martin, 1998), Alzheimer’s disease (Wolfson, 2008), certain types of memory (Johansson et al., 1999), and well-being (Weiss, Bates, & Luciano, 2008) have key genetic underpinnings. As genetics research continues, it is likely that we will have some exciting answers to the question, Why do we age?

Implications of the Developmental Forces

Although scientists do not yet have one unified theory of biological and physiological aging, the picture is becoming clearer. We know that there are genetic components, that the body’s chemistry lab sometimes produces incorrect products, and that errors occur in the operation and replication of DNA (Vintildea & Miguel, 2007). From the perspec­tive of the basic developmental forces, the biological theories provide ways to describe the biological forces. As we examine specific body systems in this chapter and health-related processes in Chapter 4, we will begin to integrate the biological forces with the psychological, sociocultural, and life-cycle forces. In those discussions, notice how changes in body systems and diseases are influenced by these other factors.

The implication of this dynamic, interactive process is that the diagnosis and treatment of health-related concerns must also include many perspectives. It is not enough to have your physi­cal functioning checked to establish whether you are healthy. Rather, you need not only a typical bodily physical but also a checkup of psychological and sociocultural functioning. Finally, the results of all these examinations must be placed in the context of the overall life span. Although scientists do not yet have a unified theory of biological and physiological aging and are not likely to in the near future (Vintildea & Miguel, 2007), such a theory would have to account for a wide array of changes relating not only to biological forces but to other forces as well. Perhaps then we’ll discover why George Foreman was still successful in the box­ing ring and Dara Torres was winning in the pool when most of their peers were watching them on television.

Or we just might discover how to reverse or stop aging. The business of “antiaging medicine,”

Physical Changes 69

products designed to stop or prevent aging, is booming. Although most researchers who special­ize in studying the fundamental mechanisms of aging largely dismiss such efforts, not all do (Juengst et al., 2003). Healthy behaviors that delay the effects of aging are legitimate activities that have a research foundation; whether they should be called “antiag­ing” is another matter (Palmore, 2007). Exercise has been shown to delay many aspects of aging; cosmetic surgery aimed at making someone look younger does not, and is likely more related to aging stereotypes than healthy lifestyles.

There are three general research-based approaches to the work aimed at slowing or reversing aging. First, the goal is to delay the chronic illnesses of old age. Second, there is research aimed at slowing the fundamental processes of aging so that the average life span is increased to over 110 years (from roughly 78 now). Third, some researchers seek to arrest or even reverse aging, perhaps by removing the dam­age inevitably caused by metabolic processes.

Research separating healthy behaviors from age denials is key (Palmore, 2007). Legitimate research sponsored by such agencies as the National Institutes of Health gets confused with counterfeit antiaging interventions. If the legitimate research unlocks the secrets of aging, then a serious public discussion is needed to prepare society for the implications of a possible significant lengthening of the life span.

Concept Checks

1. What is the basic premise of all rate-of-living theories?

2. What are the major types of cell theories? What are their similarities and differences?

3. What mechanism is thought to underlie programmed cell death?

4. How might the four developmental forces interact in the context of biological and physiological aging?