Skin

As people age, the skin tends to become thinner, less elastic, drier, and finely wrinkled. However, exposure to sunlight over the years contributes to wrinkling and to making the skin rough and blotchy. The effects of exposure to sunlight can be seen when skin that is normally exposed to sunlight, such as that on the face, is compared with skin that is usually covered, such as that on the buttocks. People who have avoided exposure to sunlight often look much younger than their actual age.

The layer of fat under the skin thins and is replaced by more fibrous tissue. The fat layer acts as a cushion for the skin, helping protect and support it. The fat layer also helps conserve body heat. As this layer thins, the skin is torn more easily, wrinkles are more likely to develop, and tolerance for cold decreases.

The number of nerve endings in the skin decreases. As a result, sensation, including sensitivity to pain, may be reduced, and injuries may be more likely. The number of sweat glands and blood vessels also decreases, and blood flow in the deep layers of the skin decreases. Normally, heat is moved from the inner parts of the body through blood vessels to the surface of the body. When blood flow decreases, less heat leaves the body, and the body cannot cool itself as well. Thus, older people are more likely to develop disorders due to overheating, such as heatstroke. Also, the skin tends to heal more slowly when blood flow is decreased.

The number of pigment-producing cells (melanocytes) decreases. Thus, the skin has less protection against ultraviolet (UV) radiation, such as that from sunlight.