Wear of the skin on your feet
By R. David Whitby, Contributing Editor | TLT Worldwide November 2025
A person’s skin is the largest organ in the body.
While watching an excellent BBC Four series of science programs on “The Secrets of Skin,” I was alerted to the fact that the skin on the soles of my feet is much thicker than on the rest of me. This is the result of the higher load on the soles of my feet and the consequent higher rate of wear of my skin.
A person’s skin is the largest organ in the body. Skin has multiple protective roles, shielding the body from invasion by microorganisms, excessive water loss or absorption, mechanical and chemical trauma and damage by ultraviolet light. It plays a crucial role in both adaptive and innate immunity. With innate immunity, the skin produces various peptides with antibacterial and antifungal properties. In adaptive immunity, antigen-presenting cells initiate T-cell responses, leading to increased levels of helper T cells. Skin also plays a pivotal role in maintaining body temperature and water balance. The skin’s endocrine keratinocytes produce vitamin D. Its exocrine functions include temperature control by perspiration and skin protection by sebum production. Sweat and sebaceous glands are crucial to these functions. The skin is equipped with nociceptors that allow for the sensation of touch, heat, cold and pain, facilitating interaction with the environment.
Human skin has three layers, the epidermis, dermis and hypodermis, which have different anatomical structures and functions. The epidermis is the thin outer layer, which is important for the protective function. The basal layers are folded to form dermal papillae. Thin skin contains four types of cellular layers and thick skin contains five.
The dermis is a thicker connective tissue inner layer that is important for sensation, protection and thermoregulation. It contains nerves, the blood supply, fibroblasts and sweat glands, which open out onto the surface of the skin and, in some regions, hair. The apical layers of the dermis are folded to form dermal papillae, which are particularly prominent in thick skin. The hypodermis is the layer underneath the dermis, and merges with it. It mainly contains adipose tissue, which is responsible for the production of vitamin D.
As noted earlier, a person’s skin varies in thickness in different parts of the body. The thickness is influenced by the thickness of the epidermal and dermal layers. Hairless skin on soles of the feet and in the palms of the hands is the thickest due to the presence of the stratum lucidum, an extra layer in the epidermis. On the soles of the feet, the average skin thickness is around 4.0 mm, while on the palm it averages 0.17 mm, and on the fingers it is 0.34 mm.
Human skin “wears” as a consequence of the natural loss and regeneration of skin cells, as part of the skin’s renewal process and due to constant abrasion. The wear rate is highest on the soles of the feet and on the hands, which is why skin is thickest there. Skin cells are also shed as a consequence of friction and abrasion by footwear and clothes.
In adults, the outermost layer of skin (the epidermis) completely renews itself on average every 28 to 56 days. This regeneration slows to up to 84 days in older people.
Humans shed roughly 200 million to 500 million skin cells per day, or about 34,000 skin cells per minute. The entire surface epidermis typically turns over every four to six weeks for most adults. Skin regenerates through a continuous process of cell production, movement and shedding in which new keratinocytes are created by stem cells in the base of the epidermis. They then migrate upward as they mature.
As cells reach the skin’s surface, they lose their nuclei, become flattened and eventually slough off to allow new cells to emerge. Minor cuts or abrasions to the epidermis can heal within weeks, while deeper wounds require months for full regeneration of structure and function. Proper diet and fluids help maintain optimal skin turnover rates.
David Whitby is chief executive of Pathmaster Marketing Ltd. in Surrey, England. You can reach him at pathmaster.marketing@yahoo.co.uk.