Has your skin ever felt tight and dry after coming out of the ocean? You're not just imagining it. Scientists from Binghamton University, State University of New York have confirmed what beachgoers have felt for years - saltwater dries out your skin - and why it happens.
Skin scientist Guy K. German discovered that exposure to saltwater significantly alters the outermost layer of your skin by increasing what's known as "drying stress." Simply put, the ocean steals your lotion.
"The salt on your skin increases drying, resulting in tighter skin," said German. "The saline that you've just come out of - the salt water - sits on your skin and messes with the way that it dries. I believe it's the drying stress that you can actually feel, the sensation that you actually get when you're on the beach."
In lab tests, German compared the impact of pure water and salt water on skin samples and found that salt water significantly increased tissue stiffness and stress as it dried.
"We did, essentially, an apples-to-apples comparison, but the one parameter that we changed is the salt in the water," said German. "If you compare salt water with fresh water, the drying stresses that build up in your skin are a lot higher, and that means the sensation of stress, the sensation of tightness in your skin, can be associated with the salt there. And it really does change the amount of stress that builds up as you're standing or sitting on the beach."
While dry skin caused by saltwater has been a long-held "urban myth," this is the first time it's been backed up by real science.
"I like finding a gap in knowledge. I like being stumped," said German. "I like coming across these things going, 'Really? Shouldn't have that been figured out in, say, the 1900s?'"
In terms of alleviating the tightness and dryness you feel after coming out of saltwater, German has a simple solution.
"What's the one thing that you find on public access beaches? Showers. You've got salt water on your skin, and salt is soluble in water, so you just take a shower."
German said that salt on your skin isn't necessarily bad for you - he personally likes the tight feeling on his skin after coming out of the water. This is simply a case of science you can observe - and feel - even on a lazy day at the beach.
"Science is everywhere. You think of these little things that happen, and there's physics going on right around you, even when you're lying on the beach, reading a book."
The paper, "Quantification of the mechanical effects of saline on human ex vivo stratum corneum," was published in the Journal of the Mechanical Behavior of Biomedical Materials.
