Researchers finally know why our skin wrinkles over time – and Silly Putty can help explain it.
Scientists at New York’s Binghamton University say experimental evidence shows that it’s a similar process to stretching out a favorite hoodie or t-shirt from overuse. Essentially, aging skin stretches in one direction, contracts in another, and then collapses. As you age, the contraction gets bigger, resulting in the formation of the skin folds and creases.
“If you stretch Silly Putty, for instance, it stretches horizontally, but it also shrinks in the other direction — it gets thinner,” Associate Professor of Biomedical Engineering, Guy German, explained in a statement. “That’s what skin does, as well.”
Wrinkles start to appear after around the age of 25 years old, according to the Cleveland Clinic. Scientists have long believed that skin wrinkles due to genetics, the effects of disease, and damage from the sun. As you get older, your skin cells are replaced at a slower rate, causing the skin’s outer layer to thin and forming wrinkles. Lines in the face, including forehead and frown lines, are largely out of our control, as they’re caused by repeated muscle movements.
Previous studies, using computational models, have also shown changes in the mechanical properties such as the elasticity and structure of the skin’s middle layer during aging. The layer, which contains the proteins elastin and collagen, is the home to hair follicles, blood vessels, and sweat glands. Until now, those changes had never been proven experimentally.
“When I got into this field, that was one of my goals – can I figure out aging?” said German. “Because if I look at the TV, the radio, online, at shops, I’m being told 1,000 different things about how to improve my skin health, and I want to know what’s right and what isn’t.”
To reach these conclusions, German and his team used a low-force tensometer to stretch out seven tiny strips of skin from people between the ages 16 through 91, simulating the forces the skin naturally experiences. The tensometer tests the maximum force a material can withstand while being pulled or stretched before breaking. The skin was collected through elective surgery or tissue from cadavers.
They found that the skin has one set of mechanical properties when you’re young. As you age, things get a bit “wonky,” German noted.
“Things degrade a bit, and it turns out the skin stretches laterally more, which causes the actual wrinkles that form,” said German. “And the reason why that exists in the first place is that your skin is not in a stress-free state. It’s actually stretched a little bit. So there are inherent forces within your skin itself, and those are the driving force towards wrinkles.”
The research, which didn’t delve into how these forces could be halted, was published recently in the Journal of the Mechanical Behavior of Biomedical Materials.
Of course, there are other things that we know affect the skin that can contribute to appearance over time. Spending too much time outside can result in a nasty sun burn, as well as age the skin prematurely with the same effect as aging naturally.
“If you spend your life working outside, you’re more likely to have more aged and wrinkled skin than those who are office workers, for example,” German warned.
