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Screening Out The Sun

Aging and Your Skin

Wrinkles, brown spots and thin, dry skin - all are signs that your skin is not as young as it used to be. While no one is immune to the march of time, there are many measures you can take now to ensure your skin ages as slowly as possible. A better understanding of how skin ages has allowed scientists to develop skincare products that not only help the skin look younger, but also help to prevent future aging.

Skin's Structure
The skin is composed of three layers. The uppermost layer (that which we see when looking at someone) is called the epidermis. The layer under this is known as the dermis. Underlying the dermis is a layer of fat cells called the subcutaneous tissue.

The epidermis is a paper-thin layer that forms a protective barrier between the body and its outside environment. Although the epidermis is thin, it consists of several layers. Epidermal cells begin their life in the lower layers of the epidermis and work their way to the surface, where they become flatter and more rigid. This outermost layer of the epidermis is called the stratum corneum. The surface cells eventually slough off and are replaced by newer cells.

The dermis consists of gel-like materials, water, elastin and collagen. It averages 2mm in thickness and houses blood and lymphatic vessels, nerve fibres, muscle cells, oil glands, sweat glands and hair follicles.

The subcutaneous layer primarily consists of fat cells. It helps to cushion the body, to store fat as an energy reserve, and to manufacture vitamin D in the presence of sunlight.

How Skin Ages
Although it may seem like it, our skin does not age suddenly. Rather, the damage we view as a natural result of aging - wrinkles, sagging and pigment changes - are cumulative: the natural result of the decades we spend simply being alive.

Damage to the skin is primarily caused by sunlight (photoaging) and by the natural process of growing older (intrinsic aging). Other contributors are mechanical stress caused by dragging or pulling the skin, and the reduction of blood flow to the skin caused by smoking and/or excessive consumption of alcohol.

Photoaging
Dermatologists estimate that 90 percent of what we perceive as skin aging (wrinkling, sagging, uneven pigmentation) is due to sun exposure. Ultraviolet light penetrates the epidermis and dermis, damaging the elastin and collagen fibres. When we are young, the damaged tissues repair themselves faster than when we are older. Over the years, the damage caused by ultraviolet light accumulates, causing the collagen and elastin to become rigid and inelastic. Eventually, wrinkles begin to form and the skin starts to sag.

Intrinsic Aging
We begin to age as soon as we are born, although the skin does not usually show signs of aging until a person reaches his or her twenties. Genetically programmed intrinsic (or chronological) aging gives rise to biochemical changes in collagen and elastin, causing the skin to become less firm and resilient. As the skin loses its elasticity, the fat cells in the underlying subcutaneous layer begin to diminish. The joint loss of elasticity and underlying support contributes towards sagging and wrinkling.

Diminishing hormone levels after menopause are believed to contribute to the thinning of the skin and associated loss of tone and elasticity.

Skin Facts
The skin is the largest organ of the body. The average adult has 2 square metres of skin (21 square feet) which weighs 3.2 kilograms (7 pounds).

In just 1 square inch of skin there are approximately 30 million cells, 100 fat glands, 600 sweat glands, 65 hairs, thousands of nerve endings and numerous muscles. The human skin has approximately 300 million skin cells and ranges in thickness from 0.5mm in the eyelid to more than 2 mm in the palms and soles.