Why fingers wrinkle when wet

Then, the water can penetrate the outer layer of your skin. This causes your skin to become waterlogged. So how does this lead to wrinkles? For a long time, people thought the water caused skin to swell up and get puffy. Now researchers believe wrinkly fingers could be an autonomic nervous system reaction.

In fact, the distinctive wrinkling is caused by blood vessels constricting below the skin. In , Mark Changizi, an evolutionary neurobiologist at 2AI Labs in Boise, Idaho, and his colleagues, suggested that wrinkling, being an active process, must have an evolutionary function. The team also showed that the pattern of wrinkling appeared to be optimized for providing a drainage network that improved grip.

But until now, there was no proof that wrinkly fingers did in fact offer an advantage. In the latest study, participants picked up wet or dry objects including marbles of different sizes with normal hands or with fingers wrinkled after soaking in warm water for 30 minutes. The subjects were faster at picking up wet marbles with wrinkled fingers than with dry ones, but wrinkles made no difference for moving dry objects. The results are published today in Biology Letters.

Hold tight Wrinkled fingers could have helped our ancestors to gather food from wet vegetation or streams, Smulders adds. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content.

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We've all seen it: take a bath or a long shower, or go swimming, and you notice the tips of your fingers and toes wrinkle. We're used to it, but do we know why this happens? Blood vessels and nerve endings play a role in skin wrinkling. We know osmosis does not account for finger wrinkling for a few reasons:. Sympathetic nerve activation is thought to be the stimulus that leads to the finger wrinkling.

The sympathetic nervous system is important in the control of a number of body functions, including heart rate and blood pressure. Unlike the rest of the body, the skin of our fingers, palms, and toes, and soles wrinkles after becoming sufficiently wet. Five minutes or so will usually do the trick.

But why do these patches of skin wrinkle? Some think that this is a biochemical reaction, an osmotic process in which water yanks a handful of compounds out of the skin, leaving an expanse of parched, pruney skin in their place. Wrinkled fingers, then, are signs of an intact nervous system.

Indeed, the wrinkling response has been suggested as a means of determining whether the sympathetic nervous system is functional in patients that are otherwise unresponsive. The wrinkle effect usually occurs after five minutes or so Credit: Getty Images.

On all of this, the scientific community has consensus. But whether and how the wet-wrinkling response may have evolved, and if it even represents an adaptation in the first place, remains a contentious debate.

Consider tyre treads. In dry conditions, smooth tyres can best maintain their grip on the asphalt, which explains why race cars typically have smooth, featureless tires.