Why does water make our skin wrinkle?

MINNEAPOLIS — Hopefully, the rain clears long enough to spend some time in the water this holiday weekend — but spend too much time in there and your fingers and toes start to resemble prunes.

So why does water make our skin wrinkle? Good Question.

Guy German is a biomedical engineer who researches the mechanics and function of soft tissues.

"Up until a few years ago, I thought and agreed with everyone else: you get in the water, the water swells your skin, your skin and you get wrinkled fingers," he said.

But researchers found people with nerve damage didn't get wrinkles.

"So it can't do with pure swelling alone," German said.

The theory now is a response from our nervous system causes our blood vessels to shrink, forming wrinkles.

"You don't have to think about breathing, you don't have to think about blinking. In a similar way, your blood vessels just do this. And they do this just naturally," German said.

Studies have shown wrinkles give us a better grip underwater — a potential survival skill back in the day.

It takes about three-and-a-half minutes in warm water for your fingertips to begin wrinkling. While in cooler water, it can take up to 10 minutes. By 30 minutes, though, you're thought to have reached maximum pruniness.

"We're not supposed to be in water for that long," German said. 

German has done studies on the effects of water on skin and found it takes about 12 hours in the water for your skin to be damaged.