What are the major physical changes frequently associated with middle and late adulthood?

Today, 13 percent of the population is over the age of 65, compared with 3 percent at the beginning of this century. This dramatic increase in the demographics of older adulthood has given rise to the discipline of gerontology, or the study of old age and aging. Gerontologists are particularly interested in confronting ageism, or prejudice and discrimination against older adults.

Aging inevitably means physical decline, some of which may be due to lifestyle, such as poor diet and lack of exercise, rather than illness or the aging process. Energy reserves dwindle. Cells decay. Muscle mass decreases. The immune system is no longer as capable as it once was in guarding against disease. Body systems and organs, such as the heart and lungs, become less efficient. Overall, regardless of people's best hopes and efforts, aging translates into decline.

Even so, the speed at which people age, as well as how aging affects their outlook on life, varies from person to person. In older adulthood, people experience both gains and losses. For instance, while energy is lost, the ability to conserve energy is gained. Age also brings understanding, patience, experience, and wisdom—qualities that improve life regardless of the physical changes that may occur.

Aging in late adulthood profoundly affects appearance, sensation, and motor abilities. An older adult's appearance changes as wrinkles appear and the skin becomes less elastic and thin. Small blood vessels break beneath the surface of the skin, and warts, skin tags, and age spots (liver spots) may form on the body. Hair thins and turns gray as melanin decreases, and height lessens perhaps by an inch or two as bone density decreases. The double standard of aging applies to men and women in older adulthood just as it did in middle adulthood. Older men may still be seen as distinguished, while older women are labeled as grandmotherly, over the hill, and past the prime of life.

During late adulthood, the senses begin to dull. With age, the lenses of the eye discolor and become rigid, interfering with the perception of color and distance and the ability to read. Without corrective glasses, nearly half the elderly population would be legally blind. Hearing also diminishes, especially the ability to detect high‐pitched sounds. As a result, the elderly may develop suspiciousness or even a mild form of paranoia—unfounded distrustfulness—in response to not being able to hear well. They may attribute bad intentions to those whom they believe are whispering or talking about them, rather than correctly attributing their problems to bad hearing. Hearing problems can be corrected with hearing aids, which are widely available.

The sense of taste remains fairly intact into old age, even though the elderly may have difficulty distinguishing tastes within blended foods. By old age, however, the sense of smell shows a marked decline. Both of these declines in sensation may be due to medications, such as antihypertensives, as well as physical changes associated with old age.

In addition to changes in appearance and the dulling of the senses, reflexes slow and fine motor abilities continue to decrease with old age. By late adulthood, most adults have noticed a gradual reduction in their response time to spontaneous events. This is especially true of older adults who drive. While routine maneuvers on familiar streets may pose fewer problems than novel driving situations, older adults' reaction times eventually decline to the point that operating a vehicle is too hazardous. However, many elderly are hesitant to give up driving because the sacrifice would represent the end of their personal autonomy and freedom.

Generally, older adults score lower overall on tests of manual dexterity than do younger adults. Older adults may find that their fine motor skills and performance speed decrease in some areas but not in others. For instance, an elderly lifelong pianist may continue to exhibit incredible finger dexterity at the keyboard, but may at the same time find that taking up needlepoint as a hobby is too difficult.

Aging also takes its toll on sexuality. Older women produce less vaginal lubrication, and the vagina becomes less stretchable because of reduced levels of female hormones. Older men are less able to attain erections and orgasms than are younger men. This may be due to reduced levels of testosterone and fewer secretions from the accessory sex glands. Likewise, older men have less urge to ejaculate, and their refractory periods, or the waiting time before they can regain an erection, may last longer.

Physical changes in sexual ability don't have to prevent older adults from enjoying sex. Although fewer in orgasmic contractions, orgasm continues to be a pleasurable event for both genders. In fact, older people may find sex to be slower and more sensual. Older women relax because they no longer fear pregnancy, older men's erections last longer, and neither is as anxious, insecure, or hurried as they may have been decades before. Regular sexual practice also may help older adults maintain their sexual interest and prowess.