Skin

Characteristic thinning, dryness, roughness, wrinkles, and lightening are to be expected. These changes may be of clinical significance, such as those altering the absorption of topical medications (see Chapter 9). Extrinsic causes of skin changes include environmental factors such as exposure to pollutants, chemicals, and solar radiation. Sun exposure, in particular, increases the extent and speed of the normal changes in aging skin. An increased incidence of skin cancer is usually the result of a lifetime of solar exposure. An increased number of allergic rashes, irritations, and infections is associated with lessened immunity. Intrinsic changes occur gradually over time and have been tied to the oxidation and cross-link theories of aging (see Chapter 3).

Epidermis

The epidermis, the outer layer of skin, is composed primarily of tough keratinocytes and squamous cells. Melanocytes produce melanin, which gives the skin color. The epidermis is in a constant state of renewal through regeneration, cornification, and shedding.

The epithelium in a healthy young adult renews itself every 20 days, whereas epithelial renewal in an older adult may take 30% to 50% longer because the keratinocytes become smaller and regeneration slows (Saxon et al., 2010). This has significant implications for the slowed wound healing seen in the older adult.

The number of melanocytes in the epidermis decreases about 10% to 20% per decade, resulting in lightening of the overall skin tone, regardless of original skin color, with a decrease in the amount of protection from ultraviolet rays (Saxon et al., 2010). Pigment spots (freckles and nevi) enlarge with age and can become more numerous with increased exposure to natural and artificial light. Lentigines, referred to as “age spots” or “liver spots,” are common in older, lighter skinned persons. They are frequently found on the backs of the hands, wrists, and faces of light-skinned persons older than 50 years.

Thick, brown, raised lesions with a “stuck on” appearance (seborrheic keratosis) are also common (Figure 4-2). They are the most common benign tumors in older, lighter skinned individuals. In one study of 22 residents of the Orthodox Jewish Home for the Aged (Cincinnati, OH), seborrheic keratosis was found in 29.3% of the men and 37.9% of the women (Balin, 2009). Dermatosis papulosa nigra, a variant of keratosis in persons with darker skin, consists of multiple, firm, smooth, dark brown to black flattened papules 1 to 5 cm in diameter (Nowfar-Rad and Fish, 2009). Although they often begin in youth, they increase significantly with age and are clinically insignificant (Figure 4-3).

Hypodermis

Beneath the dermis and above the muscles lies the subcutaneous tissue of the hypodermis. It contains connective tissues, blood vessels, and nerves, but the major component is subcutaneous fat, or adipose tissue. The primary purposes of the fat are to store calories and contribute to thermoregulation. It helps give the body its shape and acts as a shock absorber against trauma. As one ages, lean muscle is slowly replaced by fat tissue in some parts of the body.

Alteration in body weight occurs as lean mass declines and body water is lost with a concomitant higher risk for dehydration (Figure 4-4). Subcutaneous fat seems to “shift” locations with aging. Loss of fat around the orbit of the eye creates a sunken appearance. Landmarks become more prominent, and muscle contours are easily identified. Women older than 45 years begin to see the skinfolds on the back of their hands diminish, even if weight gain is substantial. At the same time, the amount of adipose tissue increases in the abdomen and, for women, in the thighs, even without a change in actual body weight. One study found that women’s waist circumference increased up to 5.7 cm in the 6 years surrounding menopause (Sowers et al., 2007).

Thermoregulation

Despite the increase in adiposity, the ability to regulate temperature is diminished by a number of causes. The risk for hyperthermia is elevated with the reduced efficiency of the eccrine glands. They become fibrotic, and surrounding connective tissue becomes avascular, resulting in a decline in the body’s ability to cool itself through perspiration; there is an increased risk for heat exhaustion and heat stroke. There is also an increased risk for hypothermia. As sebaceous glands secrete less oil, moisture evaporates more readily. Windy, dry, cold weather can accelerate loss of body heat by evaporation (Cunningham and Brookbank, 1988).

Hair

Usually the most noticeable age-related changes are hair thinning and graying from diminishing melanocytes. Regardless of gender, 50% of the population older than 50 years has gray or partly gray hair. If originally blond, the hair color may turn shades of yellow or yellow-green.

Changes in hair are sex-based. For men, vertex and frontal and temporal hair loss, or androgenic alopecia, may begin in the late teens or early 20s, and by 60 years of age 80% of men are substantially bald. The amount of hair increases in the ears, nose, and eyebrows (Saxon et al., 2010). Women may experience the same pattern of hair loss as men, but it is less pronounced. Their hair is more likely to become thinner overall and finer. Terminal hair can occur in the face and chin area after menopause with the altered balance of estrogen and androgens. For both men and women, axillary, extremity, and pubic hair diminishes and, in some instances, disappears. Absence of lower extremity hair may be misinterpreted as a sign of peripheral vascular disease. Race, gender, sex-linked genes, and hormonal balance influence the maximal amount of hair that one has and the changes that will occur throughout life. Persons of Asian descent are less hairy than white individuals, and Native Americans may have little or no body hair (Rossman, 1986).

Diffuse alopecia may occur in both sexes. It can also occur because of iron deficiency, hypothyroidism, autoimmunity, systemic diseases, medications, anabolic steroids, chronic renal failure, hypoproteinemia, or inflammatory skin diseases. Granulomatous disorders, such as sarcoidosis, and inflammatory disorders, such as discoid lupus or lichen planus can cause hair loss because of scarring. Differentiation of normal and pathological causes for hair loss is necessary.

Nails

Due in part to decreased circulation, fingernails and toenails thicken, change shape and color. Nails become more brittle, flat or concave (rather than convex), with longitudinal striations. Nails may yellow or appear grayish with poorly defined or absent lunulae. Pigmented bands may appear in the nails of persons with darker skin tones and must be differentiated from melanoma. Brittle nails with splitting ends or layers commonly occur. The cuticle becomes less thick and wide. Vigorous manipulation of the cuticle, such as in manicures, may lead to slowed nail growth. Although not a normal part of aging, onychogryphosis (thickening and distortion of the nail plate) and the fungal infection onycholysis are common. Vertical ridges (onychorrhexis) may appear as a result of poor nutrition, microtrauma, and disease (Chiu, 2000). Although the nails need more careful attention, this may be less possible because of other changes, such as loss of close vision.

See Box 4-3 for interventions that promote healthy skin and potential implications for gerontological nursing.

Structure and Posture

Changes in stature and posture are two of the obvious outward signs of aging. They occur very gradually and are caused by multiple developmental factors involving skeletal, muscular, subcutaneous, and fat tissue. Vertebral disks become thin as a result of gravity and dehydration, causing a shortening of the trunk. When combined with a slight curving of the cervical vertebra, height is lost; loss of up to 3 inches is not uncommon. The long bones, which are not affected, take on the appearance of disproportionate size. A stooped, slightly forward-bent posture is common and may be accompanied by slightly flexed hips and knees and somewhat flexed arms, bent at the elbows. To maintain eye contact, it may be necessary to tilt the head backward, which makes it appear that the person is jutting forward. Posture and structural changes occur primarily because of age-related bone calcium loss and atrophic cartilage and muscle (Figure 4-5).

Accompanying the changes in posture, shoulder width decreases because of shrinkage of the deltoid muscles and acromion processes. Chest width and pelvis width increase, and abdominal length decreases while its girth increases. An overall picture of a seemingly disproportionate individual may be seen, as if the person needs to be “stretched out a bit.”

Bones

Bones are composed of both organic tissue and inorganic products, especially minerals. Bone is a constantly changing tissue. There is ongoing and cyclic resorption (into the bloodstream) and renewal (into the bone) of minerals, especially calcium. With age, resorption is more rapid than renewal (Box 4-4). This results in reduced bone mineral density (BMD). Reduced BMD is four times more common in older women than in men. For women it is directly associated with hormonal changes following menopause, with the most rapid loss in the first 5 to 10 years. Women who are not taking hormone replacement may lose up to 50% of their cortical bone mass by the time they are 70 years old (Crowther-Radulewicz, 2010). In men, reduced BMD is primarily due to prolonged steroid use.

Excessive loss of BMD leads to in osteopenia or osteoporosis (see Chapter 15). Osteoporosis of the cervical spine results in a C-shaped or kyphotic neck. Resorption of the bone in the mandible leads to poorly fitting dentures and painful sensations when chewing or biting. But by far the most important issue related to osteoporosis is the increased risk for fall-related fractures. See Chapter 12 for a detailed discussion related to falls.

Joints, Tendons, and Ligaments

The joints make movement possible. Tendons and ligaments are bands of connective tissue that bind the bones to each other and allow the joints to articulate. Cartilage is a fibrous tissue that lines the joints and supports specific body parts, such as the ears and nose.

Age-related changes in articular cartilage result from biochemical changes: increases in transglutaminase and possibly calcium pyrophosphates. As the cartilage in the joint dries, it becomes thinner, and results in less fluidity of movement or pain as bone rubs on bone. With progressive loss of cartilage, the common pathological condition of osteoarthritis may develop (see Chapter 15). Cartilage in the nose and ears continues to grow throughout life, leading to a change in facial appearance in late life, especially for men.

Like the skin, ligaments, tendons, and joints show the result of cellular cross-linkage over time. Consequently they become dryer and stiffer, resulting in hardened, more rigid, less flexible movement and predisposing them to tearing. Further weakening occurs with disuse and deconditioning.

Muscles

The three types of muscles are skeletal, smooth, and cardiac. Skeletal muscle is essential for movement, posture, and heat production; much of it is under voluntary control. Smooth muscle, under the control of the autonomic nervous system, is found throughout the body, primarily in the lining of the organs and blood vessels. Cardiac muscle is a special muscle found only in the heart. Muscle mass can continue to build until a person is in his or her 50s. However, between 30% and 40% of the skeletal muscle mass of a 30-year-old may be lost by the time the person is in his or her 90s (Crowther-Radulewicz, 2010).

Age-related changes to muscles are known as sarcopenia and are seen almost exclusively in the skeletal muscle. Loss is caused by physical inactivity, a change in the central and peripheral nervous systems, and reduced skeletal protein synthesis.

Suggested nursing interventions to promote healthy aging of bones and muscles can be found in Box 4-5.

Heart

Electrocardiographic changes with aging under normal circumstances are minimal. PR, QRS, and QT intervals lengthen slightly. Catecholamines and certain enzymes that influence the force and speed of heart contractions diminish in concentration, resulting in a longer interval between contractions, weakened cardiac force, and a greater energy demand on heart muscle. Lower contractile strength, reduced cardiac output, and reduced enzymatic stimulation together cause the heart to respond to the work demand with less efficient performance and greater energy expenditure than would be required at a younger age (Brashers and McCance, 2010).

Contraction of the older heart is prolonged, most likely because of the slower release of calcium into the myoplasm during systole. These changes are reflected as decreased maximal heart rate, stroke volume, cardiac output, ejection fraction, and oxygen uptake and together are referred to as reduced cardiac reserve or presbycardia.

Despite these limitations, the healthy older heart is able to sustain adequate function for everyday life. Presbycardia becomes significant only when the person is physically or mentally challenged. It takes longer for the heart to accelerate to meet a sudden demand and longer to return to its resting state. For the gerontological nurse, this means that the increased heart rate one might expect to see when a younger person is in pain, anxious, febrile, or hemorrhaging may not be immediately evident. Instead, the nurse must depend on other signs of distress in the older patient. Similarly, the older heart may not be able to adequately compensate for other physical conditions that impose added cardiac demand, such as infection, anemia, cardiac arrhythmias, surgery, diarrhea, hypoglycemia, malnutrition, or circulatory overload. In these circumstances, the gerontological nurse must be alert to signs of rapid decompensation of both the previously well elder and one who is medically fragile.

Blood Vessels

The major blood vessels involved in both the coronary and systemic circulation are the veins and arteries. The coronary arteries produce a rich and dependable blood supply to the heart. The younger heart propels oxygen-rich blood through highly elastic and flexible arteries, which expand and contract depending on the body’s need for oxygen. However, several of the same age-related changes seen in the skin and muscles affect the intima of the blood vessels, especially the arteries, resulting in arterial wall stiffening and narrowing.

The most significant age-related change is reduced elasticity. Elastin fibers fray, split, straighten, and fragment. While there is little change in flow to the coronary arteries or the brain, perfusion of other tissues and organs is reduced. Reductions in the perfusion of the liver and kidneys can be significant in relation to medication metabolism (see Chapter 9).

Systolic blood pressure increases with age. Arterial wall stiffening consistently increases and baroreceptor activity decreases, which is thought to be associated with changes in catecholamine levels. Less dramatic changes are found in the veins, although they do become somewhat stretched and the valves become less efficient. Pooling of blood increases the venous pressure. This means that edema develops more quickly and there is greater risk for deep vein thrombosis, especially in the lower extremities. The normal changes with aging, when combined with long-standing but unknown weakness of the vessels, may become visible as marked varicosities and contribute to the increased rate of stroke and aneurysms in later life.

Key points in promoting a healthy heart can be found in Box 4-6.