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co2 and o2 training tables for freediving

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In our last post we talked about a very simplistic, sustained co2 and 02 tolerance table (of sorts). What we will now cover is the cornerstone of all apnea trainingtables!

If you sneak in to a freediving club, or overhear freedivers talking about their training you are bound to hear a conversation that goes something like this…

“How are your tables going?

Oh not bad, I think i have been working too much on my o2 though….

Yeah me too, did you try that c02 table i told you about?

Nah… shall we do it next session?

Yeah, guess so…”

Now, to an outsider that conversation basically sounds like two people talking junk, right? What we will now talk about will explain in relative detail the mysteries of co2 and o2 training tables.


Freediving training tables are basically a series of dives (normally static) that push our tolerances and condition our bodies to deal with either high co2 or low o2.

You need to try to do both as they both do different things. A co2 table trains you to deal with that burning feeling of needing to breathe, whilst an o2 table trains your body to operate on low o2.

Let look at co2 tables first.

A co2 table is basically a series of dives which gives you less and less time to recover in between breath-holds. So the co2 in your blood and tissues slowly creeps up and up throughout the exercise. This slow increase develops your tolerance to that nasty co2. People who have a really strong, or early desire to breathe need to concentrate on co2 tables. The maximum hold should really be no more than about 50% of your maximum breath hold time.

o2 tables work differently.

o2 tables are designed to increase you maximum breath-hold, by increasing the amount of time that you retain you breath for on each attempt. The recovery phase is fixed, unlike the co2 table, so the co2 is expelled properly in between dives. These kind of tables are important to get the body working well under the effects of low o2.

Lets have a look at 2 basic examples of both.


PREP 2.00 HOLD 2.00
1.45 2.00
1.30 2.00
1.15 2.00
1.00 2.00
0.45 2.00
0.30 2.00
0.15 2.00


PREP 2.00 HOLD 1.30
2.00 1.45
2.00 2.00
2.00 2.15
2.00 2.30
2.00 2.45
2.00 3.00
2.00 3.15

Get the idea? Its pretty simple really, so go ahead and construct your own tables to suit your requirements.

When you are training you should only focus on one type of table per session, focusing the body’s conditioning on either co2 or o2. You must also only do one table per session. When constructing your tables ensure that you do not push your limits too far by either setting your co2 hold at over 50% of your static PB or having your last 02 hold at more than 80% of your static PB. Tables are not there to push your limits, they are there to condition yourself. Each table will take quite some time to complete so  have a  patient buddy!

You can get software that will help you do your own tables. Just search the Apple store or Google Play for apnea trainers.

Remember that freediving training is all about baby steps and slow steady progress is a safe environment. Always train with a  buddy and never dive alone. Even a seemingly easy table can be deadly if conducted alone.

So now that you know what its all about, you can join in that riveting conversation about tables!


41 Responses

  1. There are apps for wp7 and android as well:

    Windows Phone
    STAmina – Free –

    Apnea for free divers – $3.99 –
    Apnea Trainer – $0.99 –
    Breath Hold – $2.99 –
    iHoldBreath – $2.99 –

    Apnea tables – Free –
    Static Apnea Trainer – Free –
    Unaerobic Apnea Trainer – Free –

  2. i understand this but when breathing (recoving) do you breath normally and when holding do you breath in as much as possible or breath out as much as possible and inhail as much as possible or just hold your breath normally?

    also im confused with the hyperventilation
    as surly you want to reduce the amount of co2 in ur body to inhail and store as much o2 as possible
    also by increasing the co2 resistance levels is surly ‘breaking your fuel gaige’ like hyperventilation tricking your body to thinking it has more oxygen (but surely your body does have more o2 as you have exhailed more co2 and made more room for o2)- (but also have made your blood more alkali)than it does as you stated or is it better to trick your body to think it has less co2 Could you please explain would be highly apprichatd as i would like to practice holding my breath and increasing the time i can breath underwater so i can come to cornwall and do both 1+2 qualification

    1. Don’t worry about trying to increase your breath-hold now… thats what we are here for. Come to Cornwall and do your course and everything will be explained and it should all make sense.
      The posts on this site are there to enhance your current knowledge and to re-enforce and remind… not so much to teach.

      I feel like that you are in danger of confusing your self to the point of entering a dangerous situation.

      Q: “surly you want to reduce the amount of co2 in ur body to inhail and store as much o2 as possible”
      A: No… Take this out of your head right now! A potentially high o2 saturation is not affected by your pre dive c02 levels in that way. Oxygen is carried by Hemoglobin and co2 is carried by blood plasma, so you are not giving oxygen ‘more room’ by reducing blood co2 levels . It is more effected by relaxation and low muscle movement.

      Q: ” by increasing the co2 resistance levels is surly ‘breaking your fuel gaige’”
      Absolutely not. Its no different than a long distance runner training to tolerate higher levels of lactic acid. C02 tolerance training is THE safest way to increase your breath-hold.

      Freediving is in many ways a simple sport, but there are reasons why there are courses and it can’t be taught with complete accuracy remotely. Like I said, these post are not here to teach from the ground up, but to clear up confusion… or to re-enforce your skills with helpful reminders.
      You dont need to have ANY experience (other than being able to swim) in order to enroll on one of our AIDA courses. We will teach you all the basics and you can learn the skills and safety techniques with professional supervision.

      1. “Oxygen is carried by Hemoglobin and co2 is carried by blood plasma…”

        This is not fully true. Basically, only about 7% of CO2 is dissolved in plasma, the rest is carried by erythrocytes, in the form of HCO3- ions (about 70%) and carbamino compounds (the rest).

      2. Hi I know I shouldn’t do co2 and o2 tables same day, but is it better to do one week co2 table the other week o2 table or switch one day o2 and one day co2, also it possible to combine square/box breathing with co2 table, like 15 minute square breathing I the morning then co2 table inthe evening, same question for o2 table

  3. Hi,

    Can you explain to me how this apnea trainer app works? It is not like the others where you have separate tables for o2 and co2 but instead they claim that the apnea training function combines both o2 and co2. Please do explain how this works. Anyone over here tried it?

    Thanks 🙂

  4. hi, could someone please explain to me how the apnea trainer app works? most apps have separate co2 and o2 tables but the apnea trainer function on this one (breathe in, hold, breathe out) claims to do both at once. please explain. thanks 🙂

    1. The PC version gives you the options to either decrease rest time or increase hold time. So that does both in one app. Ill be honest, i have never used the Iphone app… as i dont have an iphone! I was just sent the link by a buddy who uses it… so i cant help im afraid. There are loads of these apps out there now. Best thing is find one that suits you best and run with that! Dive safe!

  5. The apnea trainer app for the iphone is not really based on static apnea tables but more on yoga breathing exercises. So the approach is different it has basically 2 programs like

    Breathe in for x seconds
    Hold your breath for x seconds(twice as long as the breathe in)
    exhale for x seconds (same amount of time as the breathe in cycle)

    Breathe in for x seconds
    Hold your breath for x seconds
    Exhale for x seconds
    Hold your breath again for x seconds(this is after the exhale)

    You can modify x and over time yes your breath hold capacity and capability do increase but it’s approach is not the same as using the tables.

    1. Interesting, thanks for the info on that. I have never actually seen the app in use so its good to hear from someone who has, please feel free to suggest or link to an app that you use for the iphone.

  6. Hey guys!

    I cant find my favorite app: Iholdbreath in itunes store anymore- does anyone know where I can find it? Please email me if you know: swedma (at) gmail (dot) com

  7. Nice article, for android i find impetus timer great, sorry don’t think it is applefied

    It lets you set up your own CO2 and O2 tables in less than a minute. Its great for practicing tables on the train or in the park too, if you want to.

    I have the paid version so I can back up and save my data, it was very cheap, I have only ever paid for three apps, this, whatspp and camscanner so it must be good.

    Not a paid link just genuinely think that this is great. I use it daily at the minute at we are heading for Y-40 in a few weeks time and I want the best out of my trip there.

  8. I’m going on spring break in two and a half weeks. How often should I complete the CO2 table? Once a day? Multiple times a day? Once every few? Thanks!

      1. One more question, for a beginner, which table do you think would be more beneficial in a short period of time.

        1. Definitely focus on c02 tables, plus in your daily life try to minimise your breathing rate and depth, nothing crazy, just calm, shallow and easy (maybe pausing in between breaths for a few seconds)

  9. Hi Ian,

    I’m currently doing CO2 tables according to your “How to hold your breath for 5 minutes in 1 month – Freediving training,” article. I have two queries about the tables. (I’m not a diver, so I’m doing all of the training dry).

    As I understand that I’m supposed to take tidal breaths from the diaphram for the rest periods during the CO2 tables. Then I breathe up as normal (75% inhale, full exhale, full inhale), and then hold and enjoy the contractions (which are not nearly as bad as the burning urge to breathe that accompany them…)

    So far I’m enjoying the CO2 tables as they are, they allow me to practice breathe up, and they’re fairly zen. The contractions onset slowly, a little sooner for each hold. (Speaking of contractions, I tried a wonka table once, and I felt so bad after just 4 holds, that I quit and felt nauseated for the remainder of the day).

    Although my CO2 tolerance has improved each time, I’m already foreseeing having trouble mentally keeping it together for my 2:00 and 2:15 CO2 tables,

    My question is: will I need to breathe differently for my O2 tables? Or is it the same (i.e. tidal breaths for the rests, and normal breathe up)? Are the O2 tables for the 4th week in the chart really more about pushing through the contractions from high CO2, in ADDITION to dealing with low O2?

    1. will I need to breathe differently for my O2 tables? Or is it the same (i.e. tidal breaths for the rests, and normal breathe up)? Are the O2 tables for the 4th week in the chart really more about pushing through the contractions from high CO2, in ADDITION to dealing with low O2?


      The breathing will be the same, nice and relaxed.

      Yes the 02 tables are all about pushing your times. The c02 tables early on are there to help you get more comfortable with breath-hold.
      By pushing your times you will inherently go through some c02 discomfort as well as the contractions related to low 02.

  10. Hi Ian! Thank you for sharing this with us. My question is, after having finished the one month program, in order to progress more should I continue practicing 2 weeks co2 and 2 weeks o2 tables, or should I do a co2 table one day, o2 table the other day, or what is the best way to combine the tables? Can you also tell me why doesn’t it work better doing both o2 and co2 tables every day? Thank you!

  11. Is there a reason why I should not be doing CO2 tables daily and only once a day? Is there a reason why CO2 and O2 tables should not be done on the same day?

  12. Hi.
    Is it possible to be a 100% sure that you are not having a blackout if you’re following all safety recommendations?

  13. My previous record was at 2:37 minutes. After just doing one co2 table I waited 20 minutes and tried again and got to 3:30 minutes. Thank you very much.

  14. Hi.
    Doing the 30 day program from your site and have bought the book. Hope to do a course too. Great stuff.
    Quick Q
    The CO2 table breath-up time: is this to include the final breaths?
    The 75 inhale / full exhale / full inhale pattern takes me at least 15 seconds.
    So for example if I am on the final 15 sec round, do I literally just have no time for recovery breaths?

  15. Hi,
    Completely new to doing tables but have started out with co2 as recommended.
    I’m doing a one minute hold based on 50% of my near max 2 min resting hold.
    Problem is, this is no challenge at all. Even at the short end of the cycle (15 sec prep) I’m not getting any contractions or even mild discomfort. Should I extend my hold until there is some discomfort? And if so, how hard should these tables be? At the moment I feel like I could do 15 sec recovery and a one min hold all day long.

    1. C02 tables shouldn’t actually be the hardest thing. People expect them to be terrible, but actually they almost work behind the scenes if that makes any sense at all. Yes you can increase the time a bit if you want, no more than 75% though.

  16. Hi. Thanks for this page, it’s very interesting. I have very poor CO2 tolerance and am wondering how to work the table. I can do about a minute with lungs full, sub maximal hold. Empty lungs I feel the urge to breathe after just 15/20 secs and have to breathe around 30. Question: you have a 1:1 work : rest ratio. Does that still apply for shorter work intervals, or shall I keep the 2 minute rest to recover? I’m a very well conditioned fitness professional, long time yoga practitioner and teacher. A bit freaked out to discover just how poor my CO2 tolerance is, as my overall cv function is excellent. But I have PTSD and related anxiety so I’m guessing that might be a factor in the CO2 tolerance, or maybe vice versa..

  17. Hi, newbie here

    Is it best to switch tables training every other day, or should I go with the same table for
    A week or so, in order to get results?

    Lately I’ve been doing co2 tabs on mon, wed, friday and o2 on tue and thur

  18. Hi!
    I’m new to training my breath hold, why is it bad to do more than one table a day? What happens?
    And is it bad because your doing different tables? If so could you do two co2 tables in a day if you have a break in between, and how long should the break be. (Half an hour enough?)

  19. I am about to start training and I will also be training my dynamic apnea. Is there preference on what to do first in the day? i.e. Do dynamic apnea training in the am and then do my co2 table in the evening or are they ok to do around the same time?

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