The outside layer of our skin is like a sponge. It absorbs water. And when it’s filled with water, it expands and gets softer and more pliable. And, as you’ve noted, only the under sides of the hands and the feet prune up, especially the fingertips and the toes. That’s because the outer skin layer is thickest there.

You might think this water absorption keeps skin moist. But that’s not the case. Exposing your skin to water will dry it out. The water absorbed by the outer skin layer tends to evaporate out of it relatively quickly.

So, your skin becomes drier and drier after each cycle of getting wet and drying out again. But it would stay soft and hydrated if you were to wear something that blocks evaporation. For your hands, rubber gloves work well.

Most moisturizers work in just that way. They have ingredients that keep water from evaporating from your skin.

Moisturizers also will help prevent skin wrinkling when your hands and feet are under water. There isn’t enough water that gets into the skin to make it swell up and fold. But a little water does get in. It’s just enough to temporarily soften and smooth out the skin.