After spending enough time in the bath or swimming pool, our fingers start to look different. The skin on our fingertips becomes covered in small wrinkles. For years, the simple explanation was that the skin was simply absorbing water and swelling. In reality, the process is a little more interesting. What happens to our fingers? Finger wrinkling after being in water is an active process linked to the autonomic nervous system. When our fingers stay underwater, the small blood vessels underneath the skin constrict. This reduces blood flow and volume in the area, causing the skin to pull inward and form the familiar wrinkles. So it is not simply because the skin absorbs water? Not exactly. Water plays a role in starting the process, but the wrinkling itself appears to depend largely on the function of nerves and blood vessels. In fact, fingers with disrupted nerve supply may not develop normal water wrinkles. This is one reason the phenomenon has also been used as a simple test of autono...
