As we advance in years, our bodies inexorably change. The most visible changes of all occur in the integumentary system—our skin, hair, nails and glands. The major functions of the integumentary (skin) system are protection from environmental hazards and temperature control. The skin is the largest organ in the body. In humans, it accounts for about 12 to 15 percent of total body weight.
In general, aging skin thins as cell activity declines and as the network of elastic and collagen fibers supporting it decreases. This makes older people more prone to injury and recurring skin infections, causes the sagging and wrinkling notorious of aging, and slows skin repair.
The skin of Caucasians becomes pale with age as melanin production diminishes. Melanin is a pigment produced by cells called melanocytes and is found primarily in the epidermis, or the outer layer of skin. It contributes to the wide variety in skin color seen in different people and also helps protect skin cells from damaging sun rays. As a result of a decrease in this pigment, older people are more sensitive to the sun and tend to avoid it. Since exposure to sunlight allows the skin (along with the kidneys and liver) to produce adequate amounts of vitamin D, strict avoidance of sunlight can cause the production of Vitamin D to decrease by as much as 75%. This can then result in muscle weakness and a reduction in bone strength because vitamin D is necessary for functioning of both the muscular and skeletal system.
Glandular activity is the skin decreases and leads to dry, scaly skin. Sweat glands become less active, and at the same time blood supply to the skin is decreased. This combination makes the elderly less able to lose body heat, so overexertion or exposure to extreme temperatures can cause dangerously high body temperatures.
As you can see, aging leads to many changes in the skin. These changes can be broadly categorized as either intrinsic (true) aging or extrinsic aging (photodamage). Intrinsic aging is caused by internal factors related to degeneration of physiologic processes and results in subtle but important changes that are presumed to be due to time alone. Extrinsic aging is due to external factors such as preventable chronic exposure to ultraviolet (UV) radiation from the sun or toxic substnaces. Popular notions of “old skin” often correspond more closely to extrinsic aging than to intrinsic aging. In elderly Americans, most changes in the skin’s appearance are the result of chronic exposure to UV radiation from sunlight and occur most prominently on exposed areas of the skin. Elderly persons whose pigmentation or lifestyle protects them from sun damage often look younger than their chronological age. Some geriatric skin diseases, such as skin cancer, occur almost exclusively in extrinsic aged skin. In addition, loss of immunologic and inflammatory responsiveness is greater as a result of extrinsic aging than it is by intrinsic aging alone.
Damage due to extrinsic aging is cumulative. Preventative measures are most successful if begun during childhood. However, evidence strongly suggests that avoiding sun exposure and regularly using sunscreen, even after marked damage, achieves considerable clinical improvement. People of all ages should be encouraged to wear hats, keep their shoulders covered, and apply sunscreen before going out as part of their daily routine. Broad spectrum sunscreens with a sun protection factor (SPF) of at least 15 should be applied liberally over all exposed areas and reapplied after swimming or washing. People should especially avoid going outdoors without protection when UV radiation is strongest, usually around midday. Sunscreens also block UV-induced vitamin D formation in the skin, so people should be advised to consume vitamin D fortified milk or vitamin D supplements to safeguard against a lack of vitamin D. Moreover, cigarette smoking should be discouraged for cosmetic reasons because it just makes the extrinsic aging damage appear worse.
Not so fun fact: Most of the age-related changes that appear in the skin occur in the dermis, the middle layer of skin. Collagen fibers stiffen and elastic fibers lose their elasticity and clump together, and neither is replaced at an adequate pace. Consequently, crevices known as wrinkles form as damage continues.
Aging hair follicles in the skin might stop functioning altogether or produce thinner, finer hairs. With the decrease of melanin production, hair loses its color and turns gray or white. Some melanocytes will actually enlarge which leads to the accumulation of melanin in certain places of the skin. This is seen as blotches on the skin surface often referred to as liver spots.
Not so fun fact: Hair substantially grays in about 50% of persons by age 50, and hair loss in men begins between the late teens and late 20s. By the time they reach their 60s, 80% of men are substantially bald.
Hair loss might occur in postmenopausal women, but it is rarely pronounced. Instead, excessive or unwanted hair is more common after menopause, presumably as a result of the altered estrogen-androgen balance and its effect on hormonally sensitive hair follicles. The most common complaint is the appearance of scattered hairs in the beard areas. Even men notice increased hair length in the eyebrows, nose, and/or ears.
The overall volume of subcutaneous fat usually diminishes with age although the proportion of body fat versus lean muscle mass actually increases until age 70. subcutaneous fat serves two major purposes. First, it acts as a shock absorber that protects the body from trauma. Second, it plays a role in thermoregulation by limiting conductive heat loss. The distribution of fat changes as well; there is a relative decrease in subcutaneous fat on the face and hands with a relative increase on the thighs and abdomen. In some instances, these changes in the elderly can impair the function of subcutaneous fat, such as its ability to diffuse pressure over bony areas. This can then lead to bedsores in bedridden patients.
Not so fun fact: Differences in secondary sexual characteristics between men and women (such as hair and body fat distribution) begin to fade due to changes in levels of sex hormones. This causes people ages 90-100 of both sexes and all races to look very much alike.
So, take care of your skin by protecting it from extrinsic damage and help promote a youthful look throughout your life.Resource: AAHF