What is Sebum?
Even though you cannot see it, the outermost layer of your skin is covered with a special oil known as sebum. Sebum greases your skin and makes it waterproof. When you stay in water for a long time (at least 10-15 minutes), the layer of sebum gets washed away.
What causes the Skin to Swell?
The tough outer layer of your skin is made up of dead keratin cells. Once the layer of sebum is removed, these dead keratin cells in the skin of your hands and feet start absorbing water. This absorption of water causes the skin to swell.
Fortunately, the outer layers of your skin are firmly attached to the inner layers of your skin. This prevents your hand and feet from swelling up like balloons! The ‘hills’ of the wrinkles that you see are the areas that have absorbed water and swollen up, while the ‘valleys’ of the wrinkles are the places where the skin is attached to the inner layers of skin.
Why does this happen to Hands and Feet only?
You use your hands and feet to perform many activities, because of which they are subjected to much wear and tear. So, to protect your hands and feet from getting injured, the skin in these areas is made up of a thick layer of dead skin cells. The skin on your face, stomach, arms or legs does not contain much dead skin, so it doesn’t wrinkle.
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