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[music] Hello, I’m Dr. Neal Schultz
[pause]
and welcome to DermTV.
During the awful subfreezing weather in January, I was asked what's the one
thing you should always do to protect your skin in harsh, cold weather? I
said... as I usually do... make sure you apply moisturizers to all wind-
exposed areas of your skin before you go out every day.
Then the person asked a really interesting question... It was whether or
not a water based moisturizing lotion or cream, which obviously contains a
lot of water, can actually freeze on your face in really frigid weather
when wind chills are so low and even below freezing. What do you think the
answer is? Let's figure this out. Windchill temperatures near zero degrees
F might lead you to say "yes", but the correct answer is actually “no”...
That's because while your body's internal temperature is 98.6 degrees F,
your facial skin temperature is really about 90 F. And when you put a
lotion on your skin, the lotion very quickly becomes skin temperature. You
see, your body has a very sophisticated mechanism for maintaining a
constant and normal temperature... in both very cold and very hot weather.
In cold weather, the blood vessels in your skin constrict to decrease the
heat you would lose by bringing 98.6F blood from inside your body to the
surface of your skin, which is in contact with that very cold air. But even
by decreasing the amount of warmer, core temperature blood in the surface
of your skin, its temperature isn’t likely to go much lower than 80F, a
decrease of only about 10 degrees. But remember... the lotion stays the
same temperature as your skin, because the skin shares your body’s heat
with the lotion, to keep it at the skin’s temperature. So skin subjected to
even frigid sub zero temperatures is never going to approach the freezing
point of water… so the lotion wont freeze on your skin even though it can
freeze in the bottle... if the bottle is left outside in that same frigid
weather.