Why do fingers become wrinkled after bathing or swimming for a long time?

The skin is a wonderful and strange organ. As the body's largest organ, it's responsible for protecting you from the sun, chemicals, germs... And it does all of this while keeping your body hydrated and healthy. creates a sensation to the touch.

Guy German, Associate Professor of Biomedical Engineering, Binghamton University, State University of New York, and his team are trying to better understand the mechanics and function of soft biological tissues.

To explain what's going on, you first need to know a little about the autonomic nervous system. Functions such as breathing, blinking, heart beating or pupil constriction in sunlight all happen without you having to consciously control them thanks to the autonomic nervous system.

It also automatically controls the expansion and contraction of your blood vessels. Usually, temperature, medications, or what you eat or drink can cause blood vessels to expand or contract.

Constriction of blood vessels is also the cause of wrinkled skin after long swimming.

When your hands and feet are exposed to water for a few minutes, sweat ducts in the skin open, allowing water to flow into the skin tissue. This additional water reduces the percentage of salt inside the skin. Nerve fibers send messages about lower salt levels to your brain, and the autonomic nervous system responds by constricting blood vessels.

The narrowing of blood vessels causes the overall volume of the skin to decrease, causing the skin to wrinkle into these visible wrinkles. It's like a plump grape turning into a raisin and its appearance becoming wrinkled - more volume is lost than surface area.

This constriction of blood vessels also causes the skin to become paler - which is the opposite of what happens when your skin turns red during a very hot shower, as blood vessels dilate. The color change will become a little more obvious in people with lighter skin tones.

However, in people with nerve damage, this spasm does not occur. Blood vessels never narrow, so wrinkles never occur even if you stay in the bath for a very long time.

We know skin wrinkles as you age or when you pinch it. However, it is still a mystery why skin wrinkles and sometimes even changes color after you shower or stay in the pool for too long.

People often think that these wrinkles form because the skin absorbs water, causing the skin to swell and lose elasticity.

But researchers in the 1930s discovered that for people with nerve damage in their fingers, their bodies did not form wrinkles after bathing.

Researchers have found that wrinkled skin is better able to grip underwater than non-wrinkled skin. Better grip allows you to grasp objects more firmly. It makes walking along underwater surfaces easier and less likely to slip. Scientists also show that people with wrinkled fingers transfer objects 12% faster than people with normal fingers in wet conditions.

Going forward, Guy German's research team has conducted studies to look at changes in skin structure and function when immersed in water for long periods of time, not research on wrinkles . They are interested in skin analyzes that can be performed to assist forensic investigators after a crime or disaster. Scientists also want to learn more about footbath syndrome - skin damage caused by working in wet environments for long periods of time. They tend to affect military personnel or farmers growing crops in flooded fields, such as rice fields.

Prolonged immersion in water makes the skin more susceptible to breaking, but this weakening can take several weeks to appear.