Chapter 3: Physical Changes Associated with Aging

Identify and describe the primary theories of aging.

• Programmed Theories of Aging: Aging is genetically programmed to occur with time, and this process of deterioration eventually leads to death.

• Cellular Theories of Aging: Human aging is the result of cellular aging, whereby an increasing proportion of cells reach senescence, a terminal stage at which cells will cease to divide.

• Error Theories of Aging: Aging is due to environmental insults that result in progressive damage to living organisms.

  • Wear and Tear Theory: The body wears out over time from use and accumulated damage, much like a machine.

  • Free Radical Theory of Aging: Aging happens because unstable oxygen molecules (free radicals) cause cell damage over time. 

Differentiate between primary and secondary aging.

• Primary Aging: The gradual and inevitable process of bodily deterioration that takes place throughout life.

• Secondary Aging: Believed to be the result of disease and poor health practices such as not exercising, smoking, and an unhealthy diet.

Describe the changes in the skin with age and identify procedures to prevent or delay these age-associated changes.

Aging of the skin (cutaneous aging) is the result of both intrinsic and extrinsic aging. Intrinsic aging refers to the natural, irreversible changes that occur with time. With intrinsic aging, the skin becomes pale, thinner, and more fragile. Fine wrinkles and exaggerated expression lines are apparent, and the skin becomes dry and less elastic. Majority of the changes to the skin with age are preventable (i.e., due to extrinsic factors such as exercise, diet, exposure to sunlight, and smoking). Procedures that help delay or reduce visible aging include Botox, dermal fillers, chemical peels, laser resurfacing, and surgical options such as facelifts and blepharoplasty. 

Describe the changes in voice with age.

The changes associated with the aging voice are referred to as presbyphonia. These changes include a higher pitch voice in men and a lower pitch voice in women, reductions in volume and projection (a “thin” voice), tremor or shakiness in the voice, difficulty in being heard in noisy situations, and, for those who sing, reduced vocal endurance.

Describe the changes in hair with age.

Hair becomes thinner, coarser, and turns grey with age. Androgenetic alopecia is the most common form of hair loss in men, affecting 30–50 percent of men by age 50.

Describe the changes in each of the sensory systems with age.

• Vision: The pupil becomes smaller and less responsive to variations in light, the lens begins to lose elasticity and thickens and yellows, and the muscles that control both pupil size and the reaction to light lose strength.

• Hearing: Aging leads to two main types of hearing loss: conductive hearing loss (damage to the outer or middle ear) and sensorineural hearing loss (damage to the inner ear or auditory nerve). The most common-age related hearing loss is presbycusis, a progressive and irreversible sensorineural hearing loss resulting from degeneration of the cochlea or associated structures. 

• Taste: Current research on taste perception with age is contradictory, but most studies show a decline in taste sensitivity with age. 

• Smell: Decreased olfactory function; this decline can also negatively affect taste perception. 

• Touch: Tactile thresholds increase significantly with age, as do thresholds for pain and temperature. 

Identify the various diseases that can affect the cardiovascular system with age.

Cardiovascular disease (CVD) is an umbrella term used to describe many diseases of the cardiovascular system. Common age-related CVDs include arteriosclerosis, coronary artery disease, valvular heart disease, heart failure, and peripheral vascular disease. Stroke, which is the result of an interruption of blood flow to the brain or rupture of blood vessels in the brain, is also classified as a CVD. Most strokes are ischemic (blocked or narrowed artery), but hemorrhagic strokes (ruptured vessel) can also occur. 

Describe the changes in the digestive system with age.

Changes include a sluggish metabolism that can result in weight gain and constipation. Older adults also are more susceptible to a condition called diverticulitis, which is the development of small pouches in the lining of the colon. Many older adults can no longer tolerate coffee, alcohol, or spicy foods in the same quantity as when they were younger. Heartburn, dyspepsia (indigestion), and intestinal gas also are more common with age. 

Describe the changes in the immune system with age. 

Both the innate and adaptive immune systems weaken with age, making older adults more susceptible to infectious diseases, vaccine failure, and possibly autoimmunity and cancer. Because older adults spend more time in hospitals and care facilities, they are also at higher risk of nosocomial (hospital-acquired) infections, such as Clostridium difficile and methicillin-resistant Staphylococcus aureus (MRSA). 

Describe the changes in the metabolic system with age.

The prevalence of diabetes increases significantly with age (esp. Type 2 diabetes).

Describe the changes in the musculoskeletal system with age.

The aging process is associated with progressive declines in muscle mass and strength (sarcopenia) and reduced aerobic capacity. Most people also shrink in height with age. Weight loss later in life occurs partly because fat replaces lean muscle tissue, and fat weights less than muscle.

Describe the changes in the nervous system with age.

Common age-related anatomical changes in the nervous system include a reduction in both the size of the brain and its weight due to a decrease in the volume of the cerebral cortex. Other changes include a reduction in neurons, a decrease in the number of dendrite branches and interconnections, changes in synaptic organization, and a decline in the rate of neurotransmitter production. With aging, abnormal intracellular deposits or plaques begin to accumulate in the neurons. An excessive accumulation of these plaques results in clinical features that are similar to those seen in Alzheimer’s disease. 

Describe the changes in the reproductive system with age. 

With age, women experience a reduction in the secretion of estrogen and progesterone, and permanent cessation of menstruation (menopause), and physical changes such as breast atrophy, thinning and drying of the vaginal walls (atrophic vaginitis), and increased risk of vaginal yeast infections. Men experience a decline in the production of testosterone and sperm (male andropause or male menopause). Men also experience decreases in testicular tissue, enlargement of the prostate gland (benign prostatic hypertrophy), increased risk of prostate and bladder cancer, and erectile dysfunction. Sex drive (libido) decreases in both men and women with age. 

Describe the changes in the urinary system with age.

The kidneys get smaller and the blood flow to the kidneys decreases. The kidneys also lose the ability to balance the amount of salt and acid in the body. The tissue in the bladder loses its elasticity, which reduces the amount of urine that the bladder can hold. The muscles of the bladder also become weaker, which results in more urine being left in the bladder after a person urinates. The muscles in the pelvic floor get weaker with age (esp. women). This change can lead to involuntary loss of urine (incontinence). In men, the flow of urine can be blocked by an enlarged prostate gland. 

Describe the changes in sleep with age.

With age, total sleep time decreases. Older adults spend more time awake at night and less time in REM sleep than younger adults. The time to fall asleep at the beginning of the night is not necessarily longer for older adults, however, sleep tends to be lighter and more easily disrupted. Insomnia, the most common sleep disorder, becomes more prevalent with age.