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How scientist measure calories burned

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Found this on my search to try to find a precise calculator that measures the calories I burn based on my weight.

When the body "burns" food to produce energy, oxygen is used and carbon
dioxide and heat are produced.  Scientists have developed ways to measure
the amount of calories burned in activities by measuring either of these 3
components.  The most precise is the room calorimeter where a subject may
remain for several days and the amount of heat produced by the body is
determined by measuring how much heat is absorbed by the surrounding walls. 
This is a very technical process and not easily done, but there are at
least three centers in the United States where this is measured.

It is much more common to measure either the amount of oxygen consumed or
carbon dioxide produced.  Exhaled air is collected during exercise and
the amount of oxygen used is determined.  This is also a tedious process
and requires an oxygen analyzer.  Interesting the amount of air that
is exhaled compares well with the amount of energy used, so a short-cut
method to measuring energy expenditure is measure the amount of air exhaled
and compare to a the volume expired in experiments when oxygen was actually
measured.  This is not as exact, but gives useful information.  It has even
been proposed to simply count the number of breaths taken since this also
correlates to energy expended, but you can see this would be even less

All of these methods require the use of equipment that is bulky. 
Scientists have searched for easier methods to measure energy expenditure. 
Some devices measure the amount of movement, such as a pedometer that
measures steps or accelerometer that measures movements, to estimate energy
expenditure.  This is less accurate, but very practical and yields useful

Phyllis Stumbo
University of Iowa

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Apr 12 2011 18:01
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Thanks for posting.  You wrote "there are at 
least three centers in the United States where this is measured."  
Can you please list any info on these centers?  Names or locations?  (Especially West Coast if possible.)  I created a new workout that I need to get measured for caloric expenditure.  Thank you!  - Robert


Did you notice this thread is from 2007 and the poster has not been on the site since 2008?

Google, my friend.

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