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How r u measuring your lung volume?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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New Member
Sep 11, 2003
I looked at Spirometers on E-bay once and all the modern ones where over $1,000. What are you using or are you going somewhere to get it measured?
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I got my spirometer new for $395, and my friend Steph got one off ebay for something like $200 or $150.

Eric Fattah
BC, Canada
You can also get a 'volume monitor' such as the Ohmeda volume monitor (?5420 or something). This is designed to measure inhale/exhale volume of a patient continuously, but it can double as a spirometer. You should be able to find a volume monitor on ebay for $200. There don't seem to be any for auction right now though.

Eric Fattah
BC, Canada
you could make your own... and use the water displacement method of measuring. It's good enough to measure progress and pretty close for lung volume. Some drawbacks are you have to be in the water to use it. (is that a drawback?) If you build a box that is 5 3/8 inches (136mm) square inside and about 24" tall out of plexiglas or similar, and have one end closed off and the other end setup so you can fill it with water and also have a tube in that end so you can blow the air into it (while you're under the water) to displace the water. It works out so that approx. every 1 inch of water displaced is 1/2 liter of volume.
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Eric does it the right way and Fred constructs a super measuring box. A ten cent balloon, a measuring tape and some math is almost as accurate and repeatable enough for recording purposes.
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the cheap methods?

That is fascinating. I take it you built one?

Would you mind explaining how to it with the 10 cent balloon, measuring tape, and math a little more? I’m not that sharp when it comes to science math.
another method

Another method would be to do an x-ray of the person and then approximate the volume of the lungs from x-rays,either by using manual computation,or with the help of a computer
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At the drug store I bought some cheap, round, 12 inch (30 cm) balloons. I blow the balloon up to full size to pre-stretch it and then exhale as much as possible into it on one inhale. If you slip or spill some air, it's easy to start again. The balloon should now contain your vital capacity (about 80% of your total lung volume). I use a tape measure to get the circumference in five places because the balloon is obviously not exactly round. The numbers for me are 27+ to 27.75 inches. I threw out the high and low numbers and averaged the other three to get 27.3" or (times 2.54) 69.3.. cm. Divide by 2 times PI for the radius, 11.0... The formulae for volume is 4/3.PI.R cubed in cc. Very easy with a scientific calculator and a couple strokes more with any calculator.

I don't want to talk down to anyone but, let me steer you through mine.

11 times 11 times 11 =1331 times 4 = 5324 divide 3 = 1774.6... times 3.14.. = 5575 or almost 5.6 litres which is less than 5% more than the three doctors and their expensive machines (12 measurements) calculated over the last 15 years before I started stretching my lungs.
You can also do this with and without packing to find out how much you really pack or try it in different positions to see those differences.
cheap inaccurate lung capacity method

thios is similar to freds and a do it at home method.

Fill a large bowl with an couple inches of water.
You can take a 4 litre milk container (Or bigger if you have access to a large container with a small openning) . Fill it with water. Turn it upside-down in the bowl so the openning is underwater. Then you can take a thin tube and feed it into the openning of the milk container. You then breath into the tube and displace the water with air in the container. When you are done put a hand or seal over the openning and bring out the container. Then measure how much is left in the container and subtract it from the original amount of water.

Not sure how accurate it is and finding an 8-10 litre container might be hard to do.
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Here's a pic of mine... it looks wider at the top but it is perfectly square. I take it to the pool... fill with water.. I take a breath and hold the box upright under the water , I drop under the water and blow into the tube on the side near the bottom... this displaces the water..(and causes the box to rise) and because it is a clear box.. I can bring it up until the water level in the box is level with that in the pool and that is where I take my reading. I marked the increments by just filling with measured water.


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just wondering why the following wouldn't work as a simple, accurate and super cheap approach. ...

15m of 30mm diameter clear hose on a flat surface with a 90 degree bend on each end pointing up. Fill the lot with water and my maths suggests it would be 11 liters. Exhale into one end and the water will come out the other. At the point of maximum exhale (before you take your mouth away) get your buddy to mark the tube. More simple maths gives you 1.4m of hose per liter.

What I like most about this is that it incorporates the hose and water container in to one thing you can buy at any hardware or boating store

All for the cost of a couple of bucks.

I'll try it on the weekend and let you know.

.....am I missing something here?
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Good thoughts. I am wondering though if your exhale air might bubble through the water and out the other open end of the tube, thereby not pushing the correct amount of water out? Let us know your results.

I really like how you do not have to take it to the pool though.
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for those interested including sammydive... There are some pretty decent prices on spirometer's on ebay right now. Some seemed used and some don't but still around like $50.00US on bidding. but they might go up to $100-$200US or so I am guessing.
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If you have medical insurance then you can make a simple visit to the allergist, not a bad $20 visit. They can give you print out reports of the test.

I have been using jkivi's milk jug method. It works well for me and is accurately repeatable to about 20 cc's.
Thanks for the idea.

Hello... my 2 cents:

I read that inflating a balloon was not exactly accurate because when you blow into it, some pressure builds, and in fact due to the ballon pressure, the volume in it is a little smaller that the V
you have in your lungs. So my measure method was:
Inflate and deflate a couple of times a ballon, to free it from its presure and then fill it as much as i could in a single breath. Prepare a mettalic bowl full of water with a volume rule at one side (those are used to cook). See what the volume is without the ballon in, submerge the ballon ENTIRELY and measure the volume now. The difference (i.e: the volume of water displaced by the ballon) is the VC you have in your lungs.

Accuracy: With this method, I measured myself 6.5 liters of VC. Went to a diving medical certificate... and they measured 6.7 liters... so It's really acurate!


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