Re: Re:digital thermometers? - SPEED of temp rise in hypoT/normal people?

January 13, 2008

> It has been my experience with different digital thermometers that

> they are never correct when they beep, and need to remain under the

> tongue for a few minutes longer). I also have a B & H digital that

> works well too.

>

This makes me wonder about all these parents who get a reading of

98.6 on their kid at the beep, and think they're fine.. When they

might actually be running high.. Or people just noticing that

digital thermometers never seem to read high enough (not realizing/

thinking that it takes longer than 30 seconds to heat up the tip

evenly). So people then say that it's okay to have a low-ish temp..

One thing I've noticed (with a Walmart thermometer) is that the

SPEED at which the temperature rises seems to be different. If my

temperature eventually settles at 98.6, it rises faster than if it is

going to settle at 97.9. Since the digital thermometer (at least the

Walmart one) works by waiting until the reading doesn't change (to

within a tenth degree) within 20 seconds, a person with a higher temp

might get a more accurate reading, simply because the temperature

rises fast enough and the thermometer doesn't time out.

This would be expected from thermodynamics (a greater temperature

difference between the oral environment and the ambient temperature

would cause a change quicker). But I wonder if something more could

be going on - a half-degree difference doesn't seem like it should

cause that much a difference in the rate of change (although I

haven't done the calculations, and couldn't without knowing what the

tip was made of, how it absorbs heat, how the thermo-electric element

works, etc) Since the body is continually maintaining its

temperature, the oral tissue will actively generate more heat as the

tip draws it away (which would depend on how quickly cells respond to

" temperature loss " ), and that response may be different for hypoT and

non-hypoT people.

Has anyone else noticed this?

Jim

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