Biological Aspects and Theories of Aging 23
AGING IS NOT DISEASE
As the focus of this chapter is on biological theory, we do not cover the numerous
and often complex biological changes that occur during the aging process; other
texts contain this information (Arking, 1998; Hall, 1984; Morrison & Meier, 2003;
Schneider & Rowe, 1995; Spence, 1989). There are general concepts useful for un-
derstanding the differences between aging as a “normal” process and the dis-
eases that often accompany the aging process.
Aging is a process that occurs throughout the life cycle, not just in later adult-
hood. Although society tends to limit aging to a process occurring in the later
years of life, in truth the aging process, the gradual wearing down of the body, be-
gins in early adulthood. Hall (1984, p. 4) has outlined criteria for examining the
process of aging: (a) Aging may be apparent throughout life but is more notice-
able in the postreproductive period; (b) aging lowers the functional capacity of
cells, organs, and entire organisms; (c) aging results in the degradation of struc-
tural elements within the body; (d) aging lowers the effectiveness of the response
of the organism to internal and external factors; and (e) aging increases the like-
lihood of ultimate dysfunction: death.
Although older adults often experience several medical conditions, Hayflick
(1994) draws an important distinction between “normal” aging and age-related
diseases. Normal aging is simply the aging process. There is no “abnormal”
aging; there are no defects related to aging in the way there are birth defects. It
is important to note that both the aging process and age-related diseases pro-
duce impairments or limitations in an individual’s optimal functioning. How-
ever, age-related changes are not diseases; they are changes that occur in the
body, including a decrease in strength and muscle tone, short-term memory loss
(not related to dementia), menopause, and declines in vision and hearing. These
conditions occur as the result of numerous changes as we age, changes whose
underlying process is not perceptible by the human eye. It is estimated that
thousands of changes occur in organs and tissues, in their component cells and
molecules, and in the cement that holds cells together. Individually, these
changes are unnoticeable, but taken together, they manifest in the changes that
are associated with aging.
The aging process does not necessarily lead to illness; however, it does make
humans more vulnerable to diseases that a younger adult can defend against due
to a stronger immune system. These diseases include cancer, cardiovascular dis-
ease, Alzheimer’s disease, and strokes, conditions that, perhaps contrary to pop-
ular belief, are not part of older adulthood.
Just as aging is a process, dying is a process, one that leaves the individual vul-
nerable to various diseases that are predominant at the time of death and are
listed as the cause of death on the person’s death certificate. Although popular
thinking views the diseases as the cause of a person’s death, in reality the dying
process—that is, the changes that leave the human vulnerable to such diseases—
are the true cause of death.
Often, there is confusion about the exact cause of death. This is especially
true when an autopsy is not performed, or in those patients who have multiple
medical conditions at the time of death. Historically, physicians often attrib-
uted death to “natural causes,” which was often used as a general term for
those situations in which the physician could not identify the specific cause of
death. There are also cases in which a physician who is not clear about the exact