Primary and Secondary Aging

Secondary Aging

Many people think of aging as a one-dimensional construct, but some experts in aging have come to embrace the idea of aging as a two-dimensional construct. The first dimension is primary aging. Primary aging involves innate maturational processes and is genetic and involves hormonal and biological changes that are inevitable in all people as they age (Anstey et al., 1993). Secondary aging refers to the impact that environment, lifestyle choices, and disease have on aging (Anstey et al., 1993). The distinction between the two types of aging is critical, because for years there was an assumption that aging was a given and that little could be done to pause the aging process. However, what people have come to understand is that aging does not have to be a dramatic slide into debilitation, and that lifestyle factors can have a huge impact on how people age. People cannot avoid all of the impact of secondary aging; they will experience some impact from environment and lifestyle factors, but they can help limit that impact. However, it is difficult to separate the effects of disease from the normal aging process, because there does appear to be a cyclical relationship between illness and old-age.

Primary aging is genetic. Moreover, primary aging is going to result in some type of decay. This is due to a decline in trophic factors, which are the hormonal substances that the body produces including estrogen, testosterone, and human growth factor (Rhodes, 2001). The declines in these trophic factors lead to those things that are considered the classic signs of aging: wrinkles, hair loss, loss in hair color, shrinking, loss of bone mass, loss of muscle fiber, a decline in the senses, and a reduction in immune system performance (Rhodes, 2001). Interestingly enough, primary aging actually seems to contribute to the ability to think, which is contrary to many assumptions about aging. The "ability to understand, reflect, and interpret information actually increases with age" (Rhodes, 2001). However, the speed of thought does seem to decline with age. "The primary aging process interests scientists engaged in gerontology, geneticists and molecular biologists in particular. Most scientists specializing in primary aging believe that humans cannot avoid or even slow down the basic aging processes" (Colbourne, 2012).

There are several different theories about primary aging, and some of those theories actually counter the traditional belief that little can be done to counter the primary aging process. Three of those theories include oxidative damage, genetic limits, and caloric restriction (Bee & Bjorklund, 2010). Each of these theories explores whether primary aging is as unchangeable as has been assumed by researchers in the field, or whether there are things that people can do to prevent or slow down the elements of aging that are generally assumed to be inevitable.

The theory of oxidative damage is based on the idea that free radicals in the body damage DNA. These free radicals cause lipofuscin, which is an inflammatory build-up in cells that is believed to be the cause of a number of diseases (Bee & Bjorklund, 2010). It is believed that these free radicals can be inhibited by antioxidants. Therefore, the use of antioxidants might be a way to combat primary aging. Foods can be a wonderful source of antioxidants.

Some theorists believe that there are genetic limits that impact primary aging. According to the genetic limits theory, each species has a characteristic maximum life span. There is a correlation between the longevity of a species and the number of times its cells will divide (Bee & Bjorklund, 2010). Moreover, organisms appear to have internal clocks. Lengths of repeating DNA at the tips of cells known as telomeres function as time keepers for the organisms (Bee & Bjorklund, 2010). Furthermore, these genetic limits are not arbitrary; they are believed to be part of normal development for some cells (Bee & Bjorklund, 2010).

Finally, there is some indication that calorie intake can have a real impact on primary aging. There appear to be age-related differences in the number of calories the body metabolizes. Furthermore, severe caloric restriction seems to have promising implications for longevity. Taking calorie intake down to about half of what normal calorie consumption is increases longevity in lab animals (Bee & Bjorklund, 2010).

Secondary aging is more about the body slowing down. Secondary aging cannot be completely eliminated through lifestyle changes, but it can be slowed and controlled in many ways. With secondary aging, "The circulatory system becomes less efficient and the heart gets sluggish. The vessels that carry the blood to and from the heart become clogged and constricted. Lungs lose nearly half of their capacity by the time your parent turns 80 and the muscular-skeletal system loses its strength, giving way to stiff joints and weak muscles. This slowing down of the body's systems also affects digestion because it takes longer for food to pass through" the system (Rhodes, 2001). Secondary aging is also linked to the onset of chronic diseases (Colbourne, 2012). These chronic diseases that many people associate with old age include heart disease, diabetes, arthritis, and other physical ailments that not only limit life expectancy but can also greatly and negatively impact quality of life for patients. Many people believe that making healthy lifestyle choices, not only throughout life, but also in old-age, can reduce or slow aging. For example, physical inactivity, exposure to hazardous materials, and poor nutrition are all considered contributing factors to secondary aging (Colbourne, 2012).

The distinction between the two types of aging is considered very important because of the scientific focus on anti-aging. "Scientists disagree about the aging process and just about everything about anti-aging strategies. What is the controversy about? And how can we proceed if the science is in dispute" (Colbourne, 2012). This is due to the fact that several different types of specialists study aging, "including geneticists, molecular biologists, medical doctors, psychologists and others. These specialists attach meanings to 'aging' and 'antiaging' that are different from the traditional meaning of the words" (Colbourne, 2012).

Baltes has suggested that three major influences really impact human development. These three major influences include: normative age-graded influences, normative history-graded influences, and nonnormative life event influences (Woolf, 1998). These influences interact with one another so that one cannot really view them in isolation. "Normative age-graded influences are those influences within the life course that are correlated with chronological age. For example, marriage and retirement are two normative age-graded influences. These influences are the result of either biological or environmental determinants or an interaction of the two" (Woolf, 1998). "Normative history-graded influences are those influences within the life course that are correlated with historical time and are experienced by the majority of a culture. For example, wars and epidemics are considered history-graded events. They are normative in that they are experienced by the majority of the population during a given time. In addition, the majority of a cohort (individuals all born the same year) experience the event in similar ways. They may however affect cohorts differentially" (Woolf, 1998). Nonnormative life events take age and history influences, which are relatively stable across populations, and personalize them for the individual. "As each member of a cohort continuously experiences different nonnormative life events throughout their life course, interindividual differences increase across the life-span" (Woolf, 1998).

What this information makes clear is that aging really is an individual process. People age in different manners, and lifestyle can have a tremendous impact on how a person ages. Some of the factors that are considered to be an inevitable part of aging, such as the onset of chronic diseases in old age, can frequently be avoided through lifestyle. Of course, to maximize the benefits of lifestyle, these changes have to be implemented well before old-age. In fact, many of those factors…