The freediving breath-hold rule of thirds

One of the first questions people ask me when they do a course is…

‘How do I know that im getting close to my limit’?

I use, and teach a very simple breakdown of breath-hold. I call it…

The rule of thirds

Fundamentally every breath-hold, no matter how advanced you are can be broken down in to three sections.

1st section: No real desire to breathe. Generally comfortable.

2nd section: Starting to feel the effects of C02 build-up. A general urge to breathe. Some hints of peripheral vasoconstriction.

3rd section: The final section, dominated by diaphragmatic contractions and low 02 levels.


So what does this mean for you? Well, think of it like this….

If you are coming up at the beginning of feeling the general urge to breathe then you are robbing yourself of potentially two thirds more time underwater.

If you hit your first contraction, freak out and come up, then you could have nearly a whole third more time still to go.

If you look at the graphic above you will see the ‘danger zone’ section near the end of the final zone. This is where you are reaching your actual low 02 thresh-hold. Learning to identify this ‘zone’ is a matter of progressive training.

Extending the rule!

As we progress in our training, we can extend each third, thereby extending our maximum breath-hold. We start to increase our c02 tolerance, so we feel the onset of the 2nd third later and can deal with it for longer when it does arrive. We can increase our body’s ability to work on lower than normal oxygen levels, thereby extending the final third as well.

The danger zone.

The most dangerous part of any dive is of course when the partial pressure of oxygen in the brain gets to a point where it can no longer sustain consciousnesses. As we progress with our training we slowly push of c02 threshold back (we also push our 02 threshold back, but often slower as it is more closely connected to fitness and condition), learning to deal with the 2nd and final third and moving us closer to the ‘Danger zone’. This may take months or years to achieve.

In-fact, new freedivers (as long as they follow training guidelines and have formal training) are often less likely to blackout/loose motor control than some more advanced divers, simply as they as new divers have a lower tolerance to c02 so will come up sooner, far away from the ‘danger zone’. A more advanced diver, with a higher c02 tolerance will often push through the 2nd third and the final third all the way to their low 02 threshold therefore risking loss of motor control or blackout. The c02 safety zone is critical and is what keep us diving within our limits, respect it.

Be safe!

Remember, this is a VERY rough guide to breath-hold and the sensations within it. It gives us as freedivers something to focus on when we are training, and is especially useful for new freedivers to judge where they are in their breath-hold.

Before you try any extended breath-holds, please consider signing up for an accredited freediving course with a school such as ours. Always dive with a buddy, never dive alone!

never freedive alone

Comments 16

  1. Is it possible for me, a 71 year old woman to learn free diving? I am a very avid swimmer – spend between 2-3 hours in the pool every day – swim 10 lengths at a time & take 1-2 minute breaks after every 10 lengths.

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  2. Your website has just blown my mind! I simply had no idea you could train yourself so dramatically. I really connected with your “5 minutes in 30 days” challenge and so after reading all i could on your site, I did my baseline hold, made my tables, and have begun my month to really try to reach 5 min. Success would really blow my mind!
    Q: in my first two weeks, should I be doing only one A table attempt every other day, or many?

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  3. Hi, is it true that when u begin to get the contractions the diving reflex gets stronger therefore conserving even more oxygen. I think I saw this on Freediver Youbuur’s channel. Could this help u save even more oxygen rather than hyperventilating ( ps I know it’s bad cause changes pH of blood and blah blah blah ^^)

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      Its no that its getting stronger its just another phase. The body is physically responding to lower 02 levels by trying to activate the inspiratory muscles.
      It does signal the release of red blood cells from the spleen, that might be where you are getting confused.

  4. Hey does anyone have any pointers for me I want to increase my breath hold time but i never actually don’t feel the urge to breath ( i always feel the urge to breathe )( this pages rule of thirds says a third of my breath hold I shouldn’t even need to breath ) i am following the instructions on the “How to hold your breath for 5 minutes in 1 month – Freediving training” page on this same site.

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      Try to focus on what you are actually feeling. Is it a feeling of fullness? this is probably just that, and it will pass in time. or is it a feeling of panic? again, same thing, with repetition it will get better and you can start to enjoy that first relaxing phase of not needing to breathe.

  5. I am a 55 yr old 200 lb semi-sedentary individual. In my younger years I was an avid swimmer (Over 5 mi. per week) & SCUBA diver and up to age 40 I was pretty active , 160 lbs and in great shape (bike, surf, swim 3-5 time a week). I decided to become active again and as part of the training regime I want to take on Freediving. Right now I can hold my breath for 1 m 40s and my goal is to be able to do 5 min in 1 year and freedive to at least 30 M.

    My question is, is this an over-optimistic goal or should I set a different goal?



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      Its optimistic but not impossible, it really depends on how much time you train. I would say that there are dangers of over stretching yourself. 1: you put yourself in a much higher risk of blackout . 2: you may never actually enjoy the sport!
      The depth goal may be harder to achieve as its not all about determination but some physiological factors as well, namely equalisation (which is ALOT harder than when scuba diving).
      Just remember to get your fist course booked in early season so you have the time to get going in the rest of the season.

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