Most people could easily describe the outward appearance of an aging face: changes in facial shape; increased prominence of certain features, such as the nose; decrease in the vertical height of the mouth; recession of the gums and teeth; and loss of hair and skin color. In addition, you frequently find accentuation or wrinkling of the natural action lines of the face, sagging, jowl and pouch formation, generalized dryness (often severe), and laxity and inelasticity of the skin.
Dermatologic researchers and others interested in the aging process are actively investigating the precise nature of the structural and functional alterations in the skin that account for aging. Although we have learned much in the past decade, we do not, unfortunately, have all the answers yet. We do know that as skin ages, it tends to produce fewer new cells, and that damaged cells are repaired less quickly and less effectively. At the same time, cells in the horny layer lose some of their ability to adhere to one another. The epidermis and dermis become thinner, and the horny layer becomes less protective, dryer, and rougher. Furthermore, melanocytes become fewer in number, accounting for the development of patchy areas of skin-color loss.
Aging also results in changes in the fat distribution of the skin. Thinning of the subcutis occurs in certain areas, particularly the face, hands, feet, and shins, which means that the skin no longer feels as thick as it did before. Fat is typically redistributed to the waist in men and the thighs in women. At the same time, basal metabolism slows and life-styles become increasingly more sedentary. These changes result in the appearance and persistence of unsightly bulges.
Age affects both hair color and hair growth. Hair graying and whitening, like skin color loss, is linked to age-related decreases in melanocyte numbers and functioning. Most people (women as well as men) also experience thinning of their hair, perhaps a slowing growth rate of their hair, and even the thinning of the caliber of their hairs in certain locations. Conversely, in some areas, such as the ears, nose, and eyebrows of men, and upper lip and chin of women, previously fine, barely perceptible hairs often become thicker, more visible, and cosmetically compromising.
Equally dramatic changes in the dermis occur with natural aging. Cell numbers generally decrease and the dermis becomes thinner; as a consequence, the dermis is less capable of retaining its moisture content. In addition, the number of dermal blood vessels decreases and nerve endings become abnormal, leading to altered or reduced sensation. Wound healing is likewise generally compromised and there is usually a reduced ability to clear foreign materials and fluids. Finally, increasing rigidity and inelasticity of dermal collagen and elastin fibers contribute to wrinkling and sagging of the skin. Although some people mistakenly maintain that the loss of tone in the muscles responsible for chewing, laughing, eating, and so on contributes to the development of wrinkles and sags, this is untrue. Performing muscle toning or isometric exercises has absolutely no beneficial effect in eliminating or reducing wrinkles and sags.
Finally, the amounts of eccrine and apocrine sweat secretion become diminished with age as the number of eccrine glands and the size of apocrine glands decrease. As a consequence, the need for antiperspirants and deodorants is lessened. Sebaceous gland output diminishes, contributing in part to the generalized dryness and roughness so characteristic of aging skin.
The more you know about your skin and what happens to it as the years go by, the less likely you will be to fall for exaggerated or phony claims for skin-care products or services. You will also find this information useful for better understanding the chapters that follow. Simply knowing something about skin basics enables you to be a more discriminating consumer, which in the long run can save you a lot of time, money, and dashed hopes.