Living well versus living longer
The relevant issue is not only how long we live, but how well we live. In medical terms, this means looking at morbidity (which refers to illness, disability, and disease) as well as mortality. Much will depend on the way a longer life span is achieved, which can happen through compressed morbidity, decelerated aging, or arrested aging. In the first case, people live well into old age, relatively free of disease, and then die within a short period of time. The second profile represents a general slowing of aging, with an extension of the old age period (as is attempted today in developed nations). The third possibility represents a stopping or even reversing of the aging process, such as by resetting the biological clock, which could result in restored vitality and rejuvenation among the old (as in the movie Cocoon). Figure 1.3 depicts these three profiles of morbidity, recognizing that many other shapes are possible in years to come. For completeness, we add a fourth profile, which is still prevalent in developing nations and historically represents much of the human experience. This profile depicts a rather short life burdened by disease and illness for a major portion of the person's time on Earth, assuming they are lucky enough to reach maturity in the first place.
Figure 1.3 Quality of life profiles
Many of the improvements in morbidity are due to reductions in death from childbirth or childhood illness, as well improvements in sanitation (see Chapter 2, "A Short History of Biomedicine"). One of the most valuable medical inventions is the lowly toilet, which helped improve hygiene and sanitation.8 Over the past 200 years, however, an additional factor has been the overall improvement in the size, health, and robustness of human beings. In earlier times, malnutrition affected the unborn, children, and adults alike, making them all susceptible to infections and maladies that stronger humans can bear. Path-breaking research by Robert Fogel, an economic historian who won the Nobel Prize in economics in 1993, underscores the importance of what he termed "technophysio" evolution. Fogel's team painstakingly studied the medical records of about 45,000 Union Army veterans and then compared this Civil War generation with soldiers in World Wars I and II. Using detailed medical records, pension files, and death certificates, they examined morbidity and mortality over a century.9 The research shows how humans were gradually liberated from centuries of malnutrition, resulting in a doubling of life expectancy since 1700 and an increase in body mass of more than 50%. For example, an average Frenchman alive in 1790 weighed around 110 pounds when in his 30s, compared to weighing more than 170 pounds today. Since 1775, Norwegian men have added 5.5 inches to their height. In India, life expectancy at birth has risen from 29 to 60 since 1930.
Of children born around 1840, about 25% died in infancy and another 15% died before they turned 15. Those who reached adulthood suffered from persistent malnutrition. This contributed to chronic conditions such as back pain, diarrhea, and cardiovascular disease, as well as acute infections such as typhoid, tuberculosis, measles, rheumatic fever, and malaria (which was endemic throughout the southern United States). In addition, dental problems, including loss of teeth, were common. These various health stresses took their toll, especially because most jobs entailed tough physical labor. According to Fogel's records, Union Army veterans suffered an average of 6.2 chronic conditions in their mid- to late 60s (if they lived that long), compared to fewer than two such conditions today for the same age group. Over the past 200 years, humans have become physically stronger, thanks to better nutrition, fewer infections, better sanitation, and safer work environments, resulting in a species better able to withstand the medical slings and arrows of life.
Apart from objective measures of morbidity, how we feel and experience the quality of our life is ultimately most important. Quality of life perceptions are hard to measure because they necessarily rely on subjective reports by respondents. People who end up in a wheelchair, for example, might report being happier after a while than they were before. Elderly people often consider the golden years their finest, even though they are burdened with illness, disability, and the deaths of loved ones. Social scientists measure perceived quality of life in several ways, including survey questions and interviews. They validate their measures by correlating them with, say, depression or suicide statistics, to arrive at yardsticks that can be compared over time and across cultures. An important proxy that researchers use is Subjective Sense of Well-being (SEW), a prominent component of people's perceived quality of life. Empirical studies have identified many variables that impact people's SEW.10 An important caveat is that many of these variables interact with each other and can vary considerably across subpopulations, time periods, or countries.
Demographic characteristics such as age, gender, and race all matter in people's sense of well-being. SEW tends to peak around age 65. Women report higher SEW scores than men before age 45, but lower scores than men later in life. Race seems to be a minor effect after adjusting for factors that correlate with race, such as education, income, and expectations. Education, income, and marital status are all positive influences on SEW. In terms of health as well as SEW, it pays to be married or in a loving relationship of mutual support. Not surprisingly, health is the most important influence in SEW, especially among older people, because the young often take their health for granted. Physical and social activities are also important, with special weight given to social integration through family, work, religion, and volunteerism. Social ties and group support matter especially during illness and hardship. A sense that one has control over one's life contributes strongly to SEW, as does the belief that one's life has meaning (for whatever reason).
Our sense of well-being is usually measured relative to others', and so much depends on who we compare ourselves to. Upward comparison might make us feel inadequate but can be a source of inspiration, motivation, and energy. Downward comparisons create a sense of satisfaction but might dull our ambition and desires. Early in life, upward comparison can help people realize their potential more fully; later in life, we need to accept who we are and what we have achieved, so a convergence between expectation and reality becomes important for psychological well-being. Lastly, SEW is influenced by the various life resources we accumulate over time, such as financial means, social support, and professional networks, as well as a sense of peace and wisdom that often comes only with age. Although it is beyond our scope to assess how the biosciences impact our perceived quality of life (for example, through better psychotropic drugs), we must recognize that health is just one factor, albeit an important one, in helping us live well beyond 100.