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dakotajudo
4th November 2001, 14:23
Originally posted by Robert Rousselot

Why would anyone want to know this, and what does it tell people?
Is 5,000 good or bad?


You've done an exercise to measure your vital capacity, or the total volume of air that can be moved in and out of your lungs.

Vital capacity depends largely on your body type; larger people have large VC's. I used to know a simple rule of thumb for predicting VC from bodyweight, but I've forgotten the exact conversion. IIRC, 5000 cc is about normal for a person 5'8"-5'10", 160-220 lbs. You might be concerned if you taller than 6'4".

VC values significanlty lower than normal are indicative of respiratory disease, such as asthma or emphysema.

You can find more details at
http://www.asthmatoday.net/function.html or
http://jan.ucc.nau.edu/~daa/lecture/pft.htm

Joe Kras
10th November 2001, 02:59
Originally posted by Robert Rousselot
When I blew into it measured a little over 5,000, I am guessing it was c.c..
Why would anyone want to know this, and what does it tell people?
Is 5,000 good or bad?


As Kent and Peter have stated, it is your vital capacity, which is only one test included in "pulmonary function tests".

What I find most useful in interpreting "PFT's" is a combination of the vital capacity (VC), forced expiratory volume in 1 second (FEV1), and the ratio of FEV1/FVC.

The second article that Peter posted does a good job of describing how the two numbers, and their ratio to each other, are important in differentiating and following people with a variety of pulmonary diseases.

Another number, the FEV25-75, which measures the volume exhaled during the middle 1/2 of forced exhalation, is better at detecting early obstructive disease (emphysema).

But you can always use Joe's seat of the pants measures of pulmonary function:

1) Can the person walk up 2 flights of stairs without stopping?

2) If limited from the above because of orthopedic reasons, can you blow out a match 6" from your mouth with your mouth open?

If you can do either of the above, you've got at least relatively normal lung function.

Regards,

Joe Kras
St. Louis, MO USA