How much water is absorbed through the skin while showering?
I believe that the skin is waterproof, so none. If there are any exceptions to this, then I am unaware of them.
Just as a little side note, I did a quick google to varify what I thought, and found this:
From an otherwise quite good article about the skin: http://www.apologeticspress.org/modules.php?name=Read&itemid=2581&cat=11
It amused me somewhat.
The skin is most defintiely not waterproof. One of its primary functions is to regulate water!
If the skin were waterproof, we wouldn't look like a prune after getting out of the bath (or pool).
"The answer, according to Dr. Robert Polisky, a dermatologist in Elk Grove Village, Illinois, is both yes and no. Skin, which protects the body against injury, microorganisms, and chemical agents, is water-resistant but not waterproof. The protective layer is called the stratum corneum, a thin membrane of mostly dead cells that's rich in a protein called keratin and also coated with sebum, an oil secreted through hair follicles. Together they create a water-resistant barrier that protects the dermis, where the capillaries and sweat glands lie. (If you want to verify that your skin isn't waterproof, take a long bath—the prunelike effect on your hands and feet is a result of the keratin becoming waterlogged.)"
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