Quoted message said:Maybe this belongs in rec.bicycles.anatomical.weirdness instead. But:
When I get in after a ride, my belly is cold. Specifically, the skin
at the center of my abdomen, roughly a 6" diameter circle at and below
my solar plexus, feels cold to the touch. My wife confirms that it
feels cold, and we've noticed this for years. It doesn't seem to
happen to her belly.
Just now, after a short (17 mile) ride, I took out my new toy, an
infra-red surface thermometer. Checking my skin temperatures at my
quadriceps, my sides, my neck and my forehead all gave readings within
a degree of 83 degrees F. But my belly was 72.8 F. I was riding in a
thin long sleeved jersey and tights. It was about 65 degrees F
outside.
Anybody know what gives?
- Frank Krygowski
Dear Frank,
A) Your underlying stomach muscles don't do much when you bicycle, so
they don't warm up through exercise.
B) The stomach muscles that aren't doing much in the first place are
separated from the cold belly skin by a pad of fat, which is poorly
vacularized and makes a great insulator.
C) The belly skin separated by insulating fat from idle muscles is
getting direct air cooling, so it chills down nicely.
In contrast, your head and neck skin stay warm, even though they're
out in the wind blast, because there's little insulating fat and
because they get all the blood that they can handle. We lose heat so
quickly from our over-vascularized, under-insulated heads that hats
make a huge difference in staying warm. The enthusiastic blood supply
is why even superficial head and neck wounds bleed profusely. (In
contrast, fat bleeds very little.)
The skin over your quads has little insulating fat to keep it chilled
and it's warmed by the muscles working, so being in the wind blast
doesn't chill your thighs nearly as much as it chills your belly.
The sides usually have less fat than the belly pad, even with love
handles. In any case, the side aren't as directly exposed to the wind
blast and the muscles on the sides are used much more than the
abdominals when you bicycle.
For fun, use the remote thermometer to check the difference between
the palm and the back of your hand when you're just sitting at a
computer. The palm side has thicker skin and more blood supply and
will be noticeably warmer.
Years ago, I accidentally touched the top of a doctor's computer
monitor in a cramped space with the inside of my forearm. It was much
hotter than a monitor should have been, so I made a fuss and began
checking things, but the monitor mysteriously cooled down as I
examined it. The doctor listened to my puzzled explanation about his
strangely hot monitor magically cooling off and pointed out that the
skin on the forearm is actuallly much thinner and therefore more
sensitive than the thick pads on the palm--things feel hotter on your
toughened, calloused hand, even though you'd think that it was
delicate.
The effect is exaggerated by the fact that the palm of the hand is
already a few degrees warmer than the forearm.
For what it's worth, my dog's belly is about 72F, the top of his head
is about 80F, so are his sides, and his paw pads are around 90F. He's
just lying on his side, not bicycling, no windstream.
Cheers,
Carl Fogel
