Growing Older PDF

Growing Older “Aging — we are all doing it,” a subway poster proclaims in a public service effort to make younger adults appreciate older ones. Most adults do not realize that they are aging, because organ reserve, homeostasis, and allostasis (described in Chapter 11) render declines unnoticed. None...

Growing Older “Aging — we are all doing it,” a subway poster proclaims in a public service effort to make younger adults appreciate older ones. Most adults do not realize that they are aging, because organ reserve, homeostasis, and allostasis (described in Chapter 11) render declines unnoticed. Nonetheless, senescence, as the aging process is called, begins as soon as growth stops. It follows a genetic schedule set for every species, affecting skin, hair, the internal organs, and finally life itself. The pace of senescence is affected more by choice and conditions than by genes, but we all grow older every day. The Aging of the Body Every organ, every body system, and indeed every cell slows down with age. For that reason, in our culture, aging is often linked to disease and decline, but that link may be broken. Aging — everyone does it; impairment — many avoid it. THE RESPIRATORY SYSTEM An easy example of the relationship between senescence and impairment is the respiratory system. Because of homeostasis, the body naturally maintains a certain level of oxygen, so we do not need to think to breathe. Aging reduces oxygen dispersal in the bloodstream, about 4 percent per decade. Thus, older adults may become winded after running, or they may pause after climbing a long flight of stairs to “catch their breath.” That is homeostasis. However, oxygen is reduced in some people only 2 percent a decade, but an obese, heavy smoker, living in a polluted neighborhood might lose 10 percent. By age 60, they may need an oxygen mask to breathe. This was tragically evident with COVID-19, which attacked the lungs more than any other organ. Obese smokers had a far higher death rate, even with a ventilator, than others the same age who also caught the virus (Engin et al., 2020). THE SENSES Likewise, the senses become less acute over time. Each organ, indeed each part of each organ, is on a particular timetable, but they all weaken with age. For example, some 30 distinct brain areas as well as at least a dozen aspects of the eye combine to allow sight. Peripheral vision (at the sides) narrows faster than frontal vision; some colors fade more than others. Nearsightedness increases in adolescence, stabilizes, and reverses in midlife, as the shape of the lens changes. Older adults are usually farsighted; they need reading glasses. Similarly, hearing is most acute at about age 10, with particular frequencies reflecting age-related patterns. High sounds (a small child’s voice) are lost earlier than sounds at low frequencies (a man’s voice). Although some middle-aged people hear much better than others, everyone’s hearing is less acute with age. Compensation All of the senses decline with age. Some people accept these losses as inevitable, becoming socially isolated and depressed. Instead, compensation is possible in two ways. One is to increase use of the other senses and abilities. Stevie Wonder illustrates this well — he relies on hearing and touch, which have enabled him to sell over 100 million records and win 25 Grammys. The other way is more direct: Many technological and medical interventions are available for every sensory loss. All the other senses — touch, smell, taste, balance, pain — also become less acute with age, again with individual variation. As with the respiratory system, sensory loss is affected by the person’s actions, and modern technology — when the individual accesses it — can mitigate loss. The culture can reduce the harm with larger print on medicine bottles and in books, with volume adjustment and microphone sensitivity. Individuals can use glasses and hearing aids, canes and smoke alarms. As you can see, harm from age-related loss depends on both the community and the individual, a theme also apparent later in this chapter when we focus on drugs and obesity. For the senses as well as every other aspect of aging, attitude is crucial. Modern inventions can mitigate losses, but people need to choose them, and social policies need to support them. Consider hearing again. Few people use protective headphones unless required to, and few of the one in every five U.S. men aged 45–64 who admits to “trouble hearing” has a hearing aid. The problem is attitudes and priorities (most insurance does not pay for hearing aids). THINK CRITICALLY: Why are people much more likely to use glasses when sight blurs than hearing aids when sounds soften? The Sexual-Reproductive System Like every other body system, the sexual reproductive system slows down with age. Sexual arousal occurs more slowly, orgasm takes longer, fertility disappears. However, this may not be problematic. The sexual-reproductive system changes with age, but each age may have its own benefits, as you will now learn SEXUAL PLEASURE Many people find that sexual activity is maintained, and pleasure may improve with age. For example, a British study of more than 2,000 adults in their 50s found that almost all of them were sexually active (94 percent of the men and 76 percent of the women) with most quite happy with their sexual interactions (D. Lee et al., 2016). A U.S. study of 38,207 adults who were married or cohabiting found that about half (55 percent of the women and 43 percent of the men) were highly satisfied sexually. About one-third were not. Age was not the determining factor; attitudes and relationships were crucial (Frederick et al., 2017). What about single adults? They also tend to be sexually satisfied, with age not the determining factor. A U.S. study reported that although men were less active sexually as they grew older, they were not less satisfied with their sex lives in midlife than they were in early adulthood. Women reported more satisfaction with their sex lives as they grew older (Gray et al., 2019). Women’s greater satisfaction may be because of changes in society and in their attitudes, but that is not certain. What is certain is that adults vary in sex drive, experience, and pleasure. Some adults of every age are both sexually active and satisfied with their sex lives, and some are troubled or inactive. SEEKING PREGNANCY Age matters for fertility. Worldwide, primary infertility (not able to conceive naturally) affects about 2 percent of all young couples. By age 40, infertility is about 50 percent. Nonetheless, adults in the United States not only have fewer children than in previous years, but they also have them after the age of peak fertility (see Figure 12.1). FIGURE 12.1 When to Have a Baby? If the only consideration were biology, all newborns would have teenage mothers. However, 77 percent of U.S. births occur after age 24. That bodes well for children, in that parenthood needs cognitive and emotional maturity more than quick conception and easy pregnancy. The only women with increasing birth rates are adults over age 39, who bore 129,670 babies in 2019 (Hamilton et al., 2020). Although their rate of birth complications is slightly higher than for younger women, those newborns usually become healthy, well-loved children, benefitting from the emotional (not biological) maturity of their parents. As you remember from Chapter 11, most adults under age 25 postpone pregnancy. As with the aging senses, many reproductive problems can now be overcome. Some couples turn to assisted reproductive technology (ART) when they want a baby: About 2 percent of all U.S. births involve in vitro fertilization (IVF), ranging from 5 percent in Massachusetts to 0.7 percent in New Mexico (Sunderam et al., 2020). In IVF, the woman’s ova are surgically removed, and one of the man’s sperm is inserted into an ovum. If fertilization occurs and the cell multiplies, one cell can be removed and analyzed for genetic defects. If no defects are found, the remaining cells are inserted into the uterus. Those cells may implant and develop just as a natural conception: About one IVF procedure in three results in a baby (Sunderam et al., 2020). IVF is used not only to avoid genetic problems, but also to avoid infertility caused by blocked fallopian tubes, or a low sperm count, both of which are more common with age. IVF conceptions, if they implant, develop just as other embryos do. Success is partly age-related. Unfortunately, most women postpone pregnancy, and then try to become pregnant naturally in their 30s. If that fails, some couples try IVF, which is half as likely to succeed at age 40 than at age 20. Some young adults plan ahead, freezing their ova or sperm for IVF years later. This raises both practical and ethical questions (Polyakov & Rozen, 2021). Should adults in middle age be able to conceive a baby with their own gametes stored years ago? Should gametes of a stranger be used to impregnate someone? Another ethical question is whether nations should encourage adults to have more or fewer children. In the past decades, the birth rate in more than 50 nations is lower than the replacement rate. The birth rate in the United States has been lower every year since 2000, and for 2020 it was projected that the average young woman would have 1.7 children, much lower than her grandmothers had and substantially below replacement (2.1) (Hamilton et al., 2020). Choosing Motherhood In 2018, U.S. Senator Tammy Duckworth, age 50, had her second baby via IVF and won the right to bring her infant daughter to the Senate floor. Next: Will the United States continue to be the only nation (except for New Guinea) without mandated paid maternity leave? One argument for increased immigration is that most immigrants are relatively young, which will raise the overall birth rate and lead to more people of working age in the future. The same data are used to oppose immigration, because more children means more need for education. Another ethical consideration related to fertility occurs with HIV-positive adults. Three decades ago, it seemed that the moral choice would be sterilization or abortion if conception occurred, to reduce the rate of HIV-positive infants destined to be orphaned. Now, HIV-positive adults can live a long life. Antiviral drugs and cesarean sections allow women who are positive to bear HIV-negative babies, and HIV-positive men to conceive via IVF and special preparation of sperm (Wu & Ho, 2015). Given that, should HIV-positive adults be encouraged to have children? Such newborns are more often preterm (20 percent, compared to the average of 7 percent weighing under 2,500 grams), but usually they are quite healthy (Piske et al., 2021). This raises the larger question of the effect of parenthood on adult development, a question explored in Chapter 13. MENOPAUSE MENOPAUSE For most women, sometime between ages 42 and 58 (the average age is 51), conception becomes impossible. Ovulation ceases because of a marked drop in estrogen and progesterone. This is menopause. That hormone reduction leads to many physical reactions. Always menstruation and ovulation stop, but other symptoms vary: Vaginal dryness, hot flashes (feeling hot), hot flushes (looking hot), and cold sweats (feeling chilled) may be barely noticeable or deeply disturbing. The psychological effects of menopause depend on the social context. Some women are regretful and other women are relieved that pregnancy is impossible. Some women are depressed, some moody, and others energetic. Anthropologist Margaret Mead famously said, “There is no more creative force in the world than the menopausal woman with zest.” Evolutionary biologists have wondered why nature causes women to be infertile after age 50 yet live decades after that, unlike human men or primates of any other species. The dominant explanation is the grandmother hypothesis, that communities needed older, infertile women to help raise the next generation of children. Worldwide, grandmothers are vital for well-functioning families (Berger, 2019). A View From Science Hormone Replacement The history of hormone replacement therapy (HRT) reveals the need for good science. In the final years of the twentieth century, millions of women in every developed nation took estrogen to alleviate symptoms of menopause. Unanticipated benefits became apparent. Rates of osteoporosis (fragile bones), heart disease, strokes, cancer, and dementia were lower when women took HRT. Doctors prescribed estrogen pills or patches to millions of women, some of them long past menopause, hoping to reduce the diseases of old age. However, an experiment brought that practice to a sudden halt. In a multiyear study of thousands of women, half (the experimental group) took HRT and half (the control group) did not. The results were shocking: Taking estrogen and progesterone increased the risk of heart disease, stroke, and breast cancer (U.S. Preventive Services Task Force, 2002). The most dramatic difference was an increase in breast cancer, at the rate of 6 per year for 1,000 women taking HRT compared to 4 per 1,000 for women in the control group (Chlebowski et al., 2013). The women had been randomly assigned, which meant that the results were solid. The study was stopped before its planned end date because the researchers feared that the experimental group was at risk. How could the previous correlation have been wrong? In retrospect, scientists realized that women who took HRT tended to have better medical care and higher SES than women who did not. Their medical care, living conditions, and health habits were why they had lower rates of many diseases, not their HRT. Current research still finds some benefits from HRT. It relieves the symptoms of menopause, which some women find very troubling. It may decrease osteoporosis, improve hearing, and help the heart, depending on when and what hormones are taken, and on each woman’s genes, diet, and exercise (Keck & Taylor, 2018). This confirms a conclusion from all the science on adult development: Individualized health care is needed. Those background benefits of the earlier HRT women — in medical care, living conditions, and health habits — should be available to all. Beyond that, each person must decide what to do every day, guided by the research but not ruled by it. ANDROPAUSE? A complaint regarding past health research is that many studies included only men, with insurance benefits discriminating against women (Miles & Parker, 1997). Sudden, acute illnesses (e.g., heart attacks) were studied more than chronic ones (e.g., arthritis), because men experience acute illnesses and women, chronic ones. Some of that has changed in the past decades, as “Race for the Cure” to raise money for breast cancer research now attracts millions of donors. Further, approaches to illness have changed, from an emphasis on immediate surgical cure to an emphasis on social support, more a women’s response than a man’s (Lehardy & Fowers, 2020). In a welcome reversal, studies of women and menopause have led to research on male hormones. Do aging men undergo anything like menopause? Some suggest that the word andropause should be used to signify men’s age-related lower testosterone level, which reduces sexual desire, erections, and muscle mass (Ali & Parekh, 2020; Samaras et al., 2012). But the term andropause (or male menopause) may be misleading because male hormones do not drop precipitously, and men do not suddenly lose reproductive ability: Some 80-year-old men become fathers. To combat their hormonal decline, some older men take HRT, with their H being testosterone, not estrogen. The result seems to be less depression, more sexual desire, and leaner bodies. (Some women also take smaller amounts of testosterone to increase their sexual desire.) Weighing costs and benefits is essential (Rodrigues dos Santos & Bhasin, 2021). Some of the hoped-for benefits in mobility and cognition seem to reflect SES and thus are as problematic and misleading for men as for women (Kaufman & Lapauw, 2020). Older men are most likely to seek more testosterone when they are troubled by declining sexual desire and function, but some studies find that added hormones do not necessarily help (Rastrelli et al., 2019). Other benefits, to the heart or brain, do not necessarily occur (Corona et al., 2021; Yeap & Dwivedi, 2020). The lessons from women’s HRT apply to men as well: Individualized medicine is needed. Doctors and patients need to be wary of wishful thinking, a problem for adults of all genders, ages, and ethnic groups.