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How to measure the CO2 in exhale?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

Farmer Mat

New Member
May 5, 2003
for my high school diploma i have to make a work about something... i`d like to make one about freediving! i`d like to know how much CO2 i can manage and how high i can push it with training... but i need something to measure it!
Do you have any idea where i can get something like this from?
Thanks for your help
greets Mat
Hi Mat,
All you need is a Capnograph. (if U want to measure CO2 in exhaled air)

Look in a medical supplies store that works with Intensive Care Units or exercise testing equipments.

For Arterial or Venous CO2, you need a sample of blood (that means needles) and a Blood Gas Analyzer
Why not measure your lung capacity increase while you
practice? The testing would be easier.
A spirometer is a machine or tool that you blow into and
it measures your capacity. You might ask your Dr if he has one
and if so test once then do your stuff then go back a couple weeks later and test again. I'm not sure if there are cheap
ones on the market, maybe ebay? It would be easier than
the blood gas tests.
i`d like to check how much my lung capacity and my CO2 tolerance increases and additional how my heartbeat changes during a apnea over a longer time...
i think the lung capacity changes very slowly and i only have a half year of time... but i will check it anyway because we have a spirometer in our school!
-the heartrate increases quiet slowly, so it isn`t perfect to examine, but anyway interesting!
And the CO2 tolerance increases quiet fast if i start with apnea training!
Am i right with my ideas? because i should examine something which can really give me good results to present...
i hope you understand everything which i wrote :)
greets and thank for your help
The most CO2 I have ever tolerated is 10.0%.

The method I used to reach that is quite simple.

1 breath
hold for 1'30"
1 breath
hold for 1'30"

(repeat about 10 times)
then increase the holds to 2'00" for several cycles,
and finally do the last hold for as long as possible.

Totalling of about 20 cycles.

Eric Fattah
BC, Canada

are you guys going to wear wetsuits during the worlds?
i read somewhere you were thinking about no wetsuits.
if that's the case it would be cool if you guys airbrushed
your logos on your backs.
i just try to increase my CO2 tolerance and i`d like to know how it increases - i will never reach my maximum during this half year i think...
okay i could do something like you do (Eric) and compare it with a normal apnea! then i could take a look at what could be possible...
does anybody have an idea where i could get a used, a cheap or where i could lend a capnograph?
because a new one cost a lot of money - about 2500 Euro....
Try to contact a physiology laboratory or Exercise testing laboratory. Talk with phsyologist or sports medicine specialists, with a good protocol they will let you use their equipments.
Besides the post, you made another mistake, you post it in the wrong thread.
I'll respond you in the right one
If you are working at stretching and/or diving fairly intensely, you should be able to show a considerable increase in tidal volume in a lot less than 6 months. A spirometer would be great, but it is quite possible to get an accurately repeatable (good for trends) measurement with a plastic tube , a couple of clear plastic gallon jugs and a measuring cup.

Good luck with your project

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