Why do fingers wrinkle after soaking in water? Scientists finally have the answer!

After soaking your hands in water for a long time, such as after swimming, washing dishes or clothes, the fingertips will become wrinkled. Why is this happening?

Many people may rush to answer: Isn't it because the skin cells absorb too much water when soaked in water, so they swell? Is this really the case?

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Explaining wrinkled fingers with scientific phenomena

In 2003, a PhD student from the National University of Singapore published a series of papers proposing that wrinkling caused by water immersion is due to vasoconstriction .

The distal fingertips have a very high concentration of arteries and veins and are one of the few places in the body that contains a large number of "glomerular organs." These structures are composed of complex blood vessels that are involved in both sensing and regulating temperature.

Since long-term exposure to water will take away some heat, the glomerulus regulates the temperature by reducing its volume by constricting the blood vessels , which will generate a negative pressure.

The different pressures between the deep and superficial skin structures exert different downward pulls on the fingertip skin, resulting in different skin tightness and uneven skin wrinkles.

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However, when soaking in water, why do only the tips of the fingers and toes become wrinkled, while the skin on other parts of the body is basically normal?

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Why do only the tips of fingers and toes become wrinkled?

In fact, wrinkles also occur in other parts of the body, but they are not as obvious.

The subcutaneous fat of skin in different parts of the human body is different. The subcutaneous fat of skin other than hands and feet, such as legs, arms and upper body, is relatively thick and has relatively strong tension, which can support the skin well and make it more stretchable, so wrinkles will not appear.

The subcutaneous fat in the hands and feet is relatively thin. After being soaked in water, the tension of the subcutaneous fat is poor and cannot support the surface of the skin well, so raised and sunken wrinkles appear.

In addition, the stratum corneum of other parts of the body is thinner than that of the hands and feet (especially the fingers and toes), so it does not wrinkle.

So do wrinkles simply make us anxious? Do these wrinkles have any meaning to us?

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The wrinkles also have meaning.

1. Increase friction

In 2020, Nick Davis, a neuroscientist and psychologist at Manchester Metropolitan University, conducted research into the meaning of wrinkled fingers.

He measured the force required to grasp plastic objects in 500 volunteers visiting London's Science Museum. As expected, those with wet hands required more force than those with dry hands when their palms were unwrinkled.

But when their hands were soaked in water for a few minutes and wrinkled, their grip was somewhere in between, even while they were still wet.

Davis therefore concluded that wrinkles increase friction between fingers and objects.

As for the practical significance of wrinkled fingers, Tom Smulders, an evolutionary neuroscientist at Newcastle University, said, "I think the phenomenon of wrinkled fingers increasing underwater grip is related to two activities: one is to move in a very wet environment, and the other is to transfer objects underwater."

For example, wrinkling provided a crucial advantage when our ancestors were navigating slippery rocks or grasping tree branches, or when they were searching for food such as shellfish.

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2. Reflect health status

Hyperhidrosis

Patients with palmar hyperhidrosis will experience rapid wrinkling of the hands and a burning sensation after contact with water. If you also sweat excessively on your palms or other parts of your body, you need to pay attention to the possibility of hyperhidrosis.

Palmar hydrocele secondary to cystic fibrosis

Patients with hydrogenic palmar folds will develop wrinkles and nodules after soaking in water for a few minutes, and some will also have papules, edema, itching and pain.

Most people with mild palmar aquagenic folds will have their condition improve during adolescence or early adulthood, and their symptoms can be relieved by using antiperspirants or other methods.

Psoriasis, vitiligo

In addition to the fact that wrinkles may indicate disease, people who have not wrinkled their skin after soaking in water may also have some health problems. For example, people with skin diseases such as psoriasis and vitiligo take longer to wrinkle.

Review: Li Nannan Director of Hunan Science Writers Association Deputy Director of Research and Publicity Department of Hunan Science and Technology Association Second-level Researcher Chinese Science Writer (Medical)

Source: I am a great doctor

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