Key Terms

account for – быть причиной; вызывать что-либо; объяснять

adrenal – надпочечная железа

aging clock – возрастные (биологические) часы

alleviate – облегчать, смягчать

bone tissue – костная ткань

counterpart – копия, двойник, аналог, коллега, дополнение, противная сторона

dendritic – дендритический, древовидный

DHEA – dehydroisoandrosterone – дегидроизоандростерон (главный андрогенный предшественник у женщин, выделяемый корой надпочечника)

hearing loss – потеря слуха

heredity – наследственность

kidney – почка

longevity – долголетие

lung capacity – жизненная емкость легких (ЖЕЛ)

outnumber – превосходить числом

persistent sensitivity – устойчивая чувствительность

replacement therapy – заместительная терапия

substantially – существенно, в значительной степени

unsubstantiated – недоказанный, необоснованный, безосновательный

visual impairment – ухудшение зрения

The late adulthood period is marked by an increase in the physical declines that begin in the early adulthood period. Changes in brain function and sensory functions are accompanied by an increase in chronic illness.

Among the most important factors in longevity are heredity and family, health, personality characteristics, and life-style. By about age 25 women begin to outnumber men until at about age 75, when women outnumber men three to one. Differences in life expectancies for men and women are probably due to social factors such as differing health habits and work environments as well as biological factors related to the X chromosome.

Developmentalists have further subdivided late adulthood. Distinctions include the young old or old age (65-74), the old old or late old age (75 years and older), and the oldest old (85 years and older). The needs, capacities, and resources for the oldest old are often different than for their young old counterparts; however, every period or subperiod of life is heterogenous. Although many of the oldest old have some type of impairment, many others do not. Significant numbers of the oldest old function effectively and are in good health.

Biological theories of aging are divided into two camps. Microbiological theories focus on the cell and macrobiological theories focus on physiological systems. Rudman's study of human growth hormone indicates that more than one aging clock exists. Although a clock in the genes may determine longevity, another clock in the neuroendocrine system also influences aging via an adrenal hormone, DHEA.

The brain undergoes predictable changes as it ages. Neurons die, and unlike other cells in the body, are not replaced. In people under the age of 70 neuronal loss appears to be accompanied by dendritic spread that may account for the lack of functional impairment. Old negative myths about the aging brain are being replaced by more optimistic portrayals.

The senses all show some decline during later adulthood. Visual impairment and hearing loss continues to decline throughout adulthood; about 75 percent of the people over the age of 75 have a hearing problem. Taste and smell also decline with bitter and sour showing more persistent sensitivity than sweet and salty. Although painful illnesses increase with increasing age, pain sensitivity decreases.

Lung capacity does drop but older adults can improve lung functioning with diaphragm-strengthening exercises.

Aging in late adulthood does include some changes in sexual performance, more so for males than for females. Nonetheless, there are no known age limits to sexual activity.

The most frequent chronic illness is arthritis (characterized by an inflammation of the joints that produces pain, limited motion, and stiffness); followed by hypertension.

The leading causes of death in late adulthood are heart disease, cancer, and cerebrovascular disease (stroke). Life expectancy would increase substantially with the elimination of cardiovascular and kidney diseases.

Osteoporosis is a disorder causing loss of bone tissue and leads to broken bones. It is the main reason that many older adults walk with a stoop. It can be prevented by high calcium diets and estrogen replacement therapy.

Accidents are the seventh leading cause of death among older adults.

Medical advances and better health habits have led to increases in life expectancy. Life span, however, remains fixed at about 120 years. In some areas of the world, such as Russia, Ecuador, and Kashmir, large numbers of individuals live to be very old. Claims that individuals live more than 120 years are unsubstantiated.

Exercise, proper nutrition, and weight control may alleviate or at least postpone some of the more common symptoms associated with increasing age.