Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: tkeyes on 29/01/2006 20:57:05
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Why does a suntan fade when exposure to UV stops?
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Because your skin is constantly flaking off and renewing itself
Michael HAPPY NEW YEAR (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi11.photobucket.com%2Falbums%2Fa186%2Fukmicky%2Fparty-smiley-012.gif&hash=844994fd61764508c533537d6874634d)
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but this is not true in all cases. there is a big difference b/w sun tan and sun burn. sun burn is irreversible and it does not fade. Go for swimming and dont use any UV protectors and then dry yourself in the sun u will get the sun burn. Believe me it wont fade.
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but this is not true in all cases. there is a big difference b/w sun tan and sun burn. sun burn is irreversible and it does not fade. Go for swimming and don't use any UV protectors and then dry yourself in the sun u will get the sun burn. Believe me it wont fade.
As you say theirs a big difference between sun tan and sunburn, a suntan is your bodies way to naturally protect you from the effects of the sun . A sunburn damages your skin sometimes permanently. The sun also digs deeper when you burn and because it digs deeper it tans deeper layers of skin which take longer to surface and flake off
Michael HAPPY NEW YEAR (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi11.photobucket.com%2Falbums%2Fa186%2Fukmicky%2Fparty-smiley-012.gif&hash=844994fd61764508c533537d6874634d)
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I dislike sunbathing.
Why get up in the morning to spend all day laying down ?...well, I can think of a reason and it's not to damage my skin. Which ever way you look at it, a sun tan is a bad thing. It is the body reacting to too much UV...in fact...it is your skin literally being cooked.
Men are the same as women.... just inside out !!
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On a more fundamental note I think that suntans probably fade so your skin is fair enough to produce vitamin D, which is only available from fish, but is made by exposure to some UV in the skin. So your skin changes colour through the year to get the right amount of UV to stay healthy.
I have heard this is probably the reason northern europeans went so fair in the first place.
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why do we tan anyway?
every village has one !
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UV light is quite energetic and when it hits some molecules it will break bonds, damaging the molecules. If these molecules are something important - DNA for example, it can cause all sorts of problems like cancer etc.
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DAVESHORTS that is poppycock,
i can get vitamin D at my local walmart.
every village has one !
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RAY
There are two main types of vitamin D.
PLANT form is ergocalciferol vitamin D
HUMAN form is cholecalciferol vitamin D3
I believe what you get from the chemist is vitamin D which comes from plants and your body converts into vitamin D2.
The type your body needs most and which your body makes naturally from exposure to sun and is vitamin D3. and is biologically more active and much better for you than the plant form .
Michael
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I think your question should be why do our skin cells die and flake off? The answer to this is that circulation to the skin cells is compromised.
During many years of experimenting with the effects that gravity bestows us in circulation, we tilted our bed back in 1994 as mentioned many times before. one of the things we noticed was the absence of hair and skin cells in the bath tub, no tide marks, yet prior to tilting the bed, definitely hair and tide marks around the water line.
Also, old mattress which we threw out was stained with a brown tannin, obviously from sweating in the summer months.
New mattress has been in place longer than the one we threw out, yet does not have any of the brown tannin staining as the old one did.
Our Tan from the sun, now stays on our skin at least 15 times longer than it did before! I still have some evidence of tan from Holliday last summer, so does my wife.
"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
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Your skin cells dieing and flaking off is a perfectly natural process - they will enevitably get abraded during everyday life and it is easier just to grow more than to make them tough enough to last a lifetime. As you age this process will slow down with your metabolism which is why older people seem to keep their tan for longer than youngsters.
If the circulation to your skin were comprimised I would have thought it would slow down the process as there are not enough resources getting to the skin to grow more cells.
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If the circulation to your skin were comprimised I would have thought it would slow down the process as there are not enough resources getting to the skin to grow more cells.
so does that mean smokers tans last longer,due to the lack of oxygen in there blood
Michael HAPPY NEW YEAR
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Originally posted by Ray hinton
DAVESHORTS that is poppycock,
i can get vitamin D at my local walmart.
Yes unfortunately however wallmart was outside the commuting range of the average caveman, as they had yet to develop the SUV. Otherwise we would probably all have nice brown/black skins.