Hi Dr. C!
I know body temperature is set at 37 oC but is this temperature uniform throughout the body? The reason I'm asking is because my feet always feel colder than my body. I'm not sure if it is an indicator of some problem or not. Especially when I shower, if the water feels warm on my body, it will feel like 10oC hotter when I pour it on my feet! Is this normal?
Btw, Congrats for making it to CNET! =D
Hello, Kelvin Hobbes —
Well, if you’ve ever gone to buy a thermometer, you may have noticed that there are MANY different types of ‘em! Now, why would that be? Is it just because some people ENJOY sticking medical probes into their anuses, while oral-fixated wackos enjoy the feel of plastic in their mouths, and the really bizarre fetish perverts enjoy spelunking their armpits or ear canals? And why would anybody bother with those “invasive” rectal/oral/tympanic thermometers, when they make those fancy-pantsy temporal or finger-tip or ear-lobe ones now?
As you have probably guessed by now, a big part of the answer is: your body temperature is NOT uniform throughout your body. Think about the last time you tried to cook a turkey: if you laid the thermometer onto the skin of the cooked bird, the temp would be lower than if you plunge it into the poor fowl’s innards. Our body’s are the same (except with fewer feathers): our body temp is generated at the “core” of our frame, and decreases as you get farther outwards from that core.
This is why, if you went out and bought a bunch of different thermometers (pervert), you’d find that the instructions would probably tell you to “add one degree if you measure the temp in the armpit” or even “subtract one degree if you measure it in the rectum” (although, as this excellent article about interpreting your child’s temperature points out, the rectal temperature is closest to the “true” body temp.)
Now, your 2nd question about the “water feeling hotter on your feet than on your body” is just an illustration of the way your body temp tends to be lower at the further extremities of your body: our toes and earlobes (and in some people, fingers) tend to be our coldest surfaces, so water that feels tolerably warm on your already-warmer torso will feel relatively “hotter” when it hits your chilled tootsies. Your cold feet are not a problem (unless you’re having issues with relationship commitment, which is outside of the scope of this reply, haha) — they’re actually quite normal.
So, I hope that roundabout reply helped to clear things up for you. Here’s a prior post that I wrote about the oft-quoted patient fallacy that “my body temperature is always lower than normal, so 98.6 degrees is really a fever for me!”
And thanks for the congrats! Yeah, I’m not really sure what to do about my 15 minutes of fame — should I go straight to guest-judging on American Idol, or would it be better to release a pop album? ("Dr. Cranquis’ Greatest Hits, featuring Ke$ha, Diana Krall, and John Cleese!”) :p