Why your fingers get wrinkly after a long bath or swim in the pool

Difficulty: Challenger (Level 2)

We know your skin wrinkles as you age or if you pinch it. But why does skin get wrinkly and change colour after taking a bath or spending too much time in the pool?

People assume these wrinkles form when the skin absorbs water. Scientists have found this is not the case.

To explain what is happening, you need to know about the autonomic nervous system. This part of the body works without you thinking about it. For example, your heart keeps beating even when you’re sleeping. You also breathe even if you aren’t focused on it.

This system also controls the expansion and contraction of blood vessels. When your skin is in water for some time, your nerves send a message to your brain to make the blood vessels shrink. This pulls in the skin, which becomes more wrinkly (see graphic).

This constriction of blood vessels also makes the skin paler because there is less blood flowing to it.

Researchers have found that wrinkled skin improves your grip under water. It makes walking along an underwater surface easier, and you are less likely to slip. This is a fantastic feature to have evolved over time.

Your skin is your body’s biggest organ. It does a lot to keep you safe – even your wrinkles are a way of protecting you!