Teaching Hyperventilation

Hyperventilation is science, but it’s not.
If we could measure our arterial CO2 levels as we breathe up it would be science, but since we can’t then it’s not. You can't say for sure if someone is hyperventilating or not, you can only guess.
Hyperventilation can be one of the worst subjects to teach. However you approach it it’s so easy to contradict yourself.

For example, let’s take one of the scientific approaches, the volumetric one.



The average person has a tidal volume of 500ml, and breathes between 10 and 20 times per minute.
Good, so you take 500 and multiply if for 15 (which is in between 10 and 20) and you get 7.5 liters.
According to the standard definition, hyperventilation is breathing more than needed.
So if you breathe in more than 7.5 liters of air per minute, you are hyperventilating.
If this is true, all freedivers are hyperventilating.
Now consider than the standard Freediver will inhale between 50 and 75% of his VC during his breathe-up, that a standard breathe-up is 3-4 minutes, and that the breathing rhythm is 4 seconds in and 8 seconds out.
So let’s be conservative and take the lowest values.
The average male has a VC of 4.8 liters, half of which is 2.4 (breathe up volume per each single breath).
4 plus 8 equal 12 seconds, which means that in one minute our guy breathes 5 times.
Now, 2.4 times 5 = 12 liters breathed per minute (which is 62% more than the 7.5 needed) and he does that 3 whole minutes, which means a total of 36 liters of air instead than the regular 22.5.
That is surely to be considered hyperventilation. Or not?
Now go tell your students that hyperventilation is dangerous and is a big no-no in Freediving, and then you teach them to breathe like that.



So if we want to be consistent then we should teach the Tidal Volume approach.
The instructor tells his/her students that they must breathe their TV during the breathe up. This is the only way not to hyperventilate, according to volumetry.
Haha, who does it, really? Surely not many.

Then there is the confused approach: Hyperventilation is bad, but you can’t breathe normal before a dive or you won’t get anywhere and therefore a bit of over breathing is the right thing to do in order to lower down the co2 and get later contractions. But not too much, just go by feeling.
Uh-uh, now you just told your student that hyperventilation is bad, and that he should hyperventilate, and don’t clarify how much.
That’s of course what most of us do as freedivers, but can we really say it to students?

Then we have the down to earth approach.
If you don’t feel any of the symptoms of hyperventilation then you are not hyperventilating. Bit simplistic, but very easy to explain.
But can you really have noticeable symptoms even for slight hyperventilation? Just because you don’t feel anything does it really mean that you didn’t hyperventilate? It seems a little dangerous to use this with beginners, because they don’t even know how they feel, let alone how they are supposed not to feel.

So, in conclusion:
The Volumetric approach: waste 1 hour of classroom, and leaves people more confused than before.
The Tidal volume approach: unrealistic; don’t preach what you don’t practice!
The Confused approach: the most realistic, but dangerous and confusing when teaching.
The Down to earth approach: too vague and potentially dangerous.

So what do we do?
What I tell my instructors is not to make things too complicated, and not to be too theoretical.
During the breathing sessions we let them practice hyperventilation and we ask them to describe what they feel. We then let them practice proper breathing while watching out for even the lightest symptoms.
In the pool/sea I breathe with them following their own rhythm, and if after a few breaths I feel a bit funny then I assume they are hyperventilating and I ask them to slow down.
We tell students we don’t hyperventilate.
Technically it is a lie...but it's a good lie, that saves trouble and confusion. At a beginner level people don't have enough understanding to handle the complicated truth!



I can see how this subject can raise questions and disagreements, and can feed a strong debate. So feel free to leave a comment to let us know what you think and how you handle the subject with your own students :)

photo: Jacques de Vos