• Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!

What is a hook breath?

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.


Hawaiian transplant...
Sep 9, 2002

Seen it mentioned, but tried searching for it and couldn't find anything.

Thank you!
Hey Fuzz! A hook breath is something that they used to teach fighter pilots to do after coming out of pushing a lot of g's. Some have adapted it to freediving after deep dives or long breath holds. Basically the idea is to take a breath and bare down as if trying to push it into your blood stream (or like you might bare down if you were wishing you had a laxative ;) ). The idea is that taking the breath and applying pressure like that helps get more oxygen back into the bloodstream quicker. It's supposed to help speed up recovery so that you don't pass out. They teach it in some of the clinics. What I've been told is 3 good hook breaths on breaking the surface after a deep dive and then back to normal breathing with nice slow deep breaths.

Hope this helps. Maybe one of the DB physiology guru's can shed more light on the subject than I have.


Maybe I should have been more specific. The way I was taught is that you inhale, then push (bare down) for only about a 2 count, then exhale and repeat.

-Mike (again :duh )
Thank you much.

That's a perfect explanation, very appreciated. :D
Hook Breath

I wouldn't try one of those after a hot curry.:naughty :vangry
There are variations on the lengths of exhalation and the tempo of breaths, but M2's explained it.
Hook breaths are used by fighter pilots primarily while under heavy G's,when the vehicle is arcing in a position that pools blood away from the head; the main benefit of hook-breathing is to force blood up into the head, maintaining BP and keeping the supply of O2 moving.
Erik Y.
Hook breath

Just as Erik explained before:

The 'hook breath' or 'pilots anti-G breath' is inhaling, holding and at the same time pushing your breath for around 2 seconds, and let go. It gives better uptake of oxygen and pushes blood towards the brain.

At our training camp in Dahab (Jan 05-19, 2004) Wolfgang Dafert and I have been applying this technique systematically and it really works! It reduces the urge to breathe, diminishes the risk of Samba/BO and keeps the diver from ventilating frantically after a maximum dive.

B. T. W. - a detailled account of this training camp is posted in this forum under:
freediving stories: Freedivecamp in Dahab 2004.

Pictures about this camp are available on my hp either by single access (indexed),
or by starting at my picture overview from where You can skip wherever You want to.

Last edited:
Fantastic explanation Mike! Thanks! I understood hook breathing to be just simply a breath-hold-breath-hold, didn't know about the "pushing" it into the blood. I understand perfectly now as I used that during aerobatics years ago to avoid loosing conciousness during G load. I believe this is the thing the Air Force calls it the M-1 maneuver or something like that? Anyway it makes perfect sense to me how this could both elevate O2 levels in the blood and at the same time increase blood pressure.

Thanks again! That clarifies things. :D
What exactly do you mean by "pushing" o2 into the bloodstream? I think I sorta get it...
Re: Hook breath

Originally posted by Gerald
At our training camp in Dahab (Jan 05-19, 2004)
Awesome pics and reports from Dahab. I recognise most of it, and I miss it very much. Say Hi to Roland next time you're there.
Erik Y.
Hook brath + PFO ?

sounds as if hook breathing would have great potency producing right-to-left shunts in people suffering a PFO. It would consequently increase the risk of suffering a DCS after deep dives dramatically...
Any ideas / thoughts / whatever on that matter ?

Best regards,

PFO Frequency: In the US: Patent foramen ovale is detected in 10-15% of the population by contrast transthoracic echocardiography. Autopsy studies show 27% (!) prevalence of probe-patent foramen ovale. This difference is probably due to the ability to directly visualize patent foramen ovale on autopsy study, while contrast echocardiography relies on detection of secondary physiologic phenomena [...]

Medical Care: Most patients with a patent foramen ovale as an isolated finding receive no special treatment. [...]

Diagonsis: external/invasive Echocardiography


me personally rememebering Benjamin Franz suffering from a stroke in 2002 during the preparation for a world record attempt (no speculations at all on that particular case but there exists a significant correlation between pfo and strokes) , I would rather leave the technique of hook breathing apart and recommend a good safety diver and o2 inhalation after repetitive deep dives, good hydration, vitamin E, omega-3-fatty-acids and eventually some platelet aggregation inhibitor like aspirin.

yours pat
Hi pat fish,

I'm not an expert on that subject, but my thoughts are the following:

I would rather leave the technique of hook breathing apart and recommend a good safety diver and o2 inhalation after repetitive deep dives, good hydration, vitamin E, omega-3-fatty-acids and eventually some platelet aggregation inhibitor like aspirin.

Prevention of Microbubbles certainly is a good thing and the main way to go. On the other hand, I doubt that they can be avoided altogether (no scientific freediving data though. Another point why I don't unterstand that nobody seems to have done any Doppler-Research so far ! :confused: ). So given that you have some bubbles in your venous bloodstream, post-dive breathing of O2 does not help it if you are producing a right-left-shunt in the first place !

Could you give me a short description of the roles of vitamin E and omega-3-fatty-acids ? I must admit that my knowledge about that stuff is rather everyday knowledge and not very *ummmh...* in-depth.


patent foramen ovale and decompression sickness sure is an endlessly discussable theme - if you are freediving on a certain level a prophylactic examination in that term could be a way to find out if you have to worry about it. but do you know of anybody among the top freedivers in the world (reaching depths in multiple dives below 30m) who have done an echocardiography to detect a potential pfo? i don't. but considering the consequences and the frequency of pfo it's worth a discussion...

i will leave the discussion about the building up of microbubbles to someone else with a better knowledge on that (there is lots of research ahead in the field of freediving). I can shortly explain my opinion on the inhalation of o2: the size and frequency of n2 microbubbles is overall significantly reduced by the inhalation of o2 because of the wellknown effect of the increased nitrogen gradient. so the input saturation of n2 to tissues and venous system is reduced. overall probability for bigger microbubbles in the venous stream should be reduced.

for the benefits of vitamin e and omega-3-fatty-acids and especially aspirin: refer to other threads discussing this matter. generally spoken: they reduce platelet aggregation and thus the probability for strokes.

that's about it...
i agree with you - research outputs in the field of freediving are unfortunately rare ...


Last edited:
old thread I know but...

I had an echocardiogram to look for PFO when I got DCS a couple of times in a row... didn't have one though which was actually a bit disappointing as it would have at least explained why it happened! friend of mine found he had one and had it fixed - all quite easy so if you ever need it, don't worry about it! the only tough bit is sitting around topless for ages while two doctors poke around your chest with the echo machine... : ) maybe not so much a problem for the boys....
Hook Breathe-Up

If hook breathing is so good at "pushing" oxygen into the body and the brain after a long apnea, why would hook breathing not be good at getting oxygen into the body and the brain before an apnea, like statics or dynamics?

I think you're right Glen, but the effort of bearing down and pushing air out under load might negate the benefit.
What I (and others) do is to do 2X 10-second holds just before the dive. This seems to help.
Erik Y.
Hook Breath Up

I, too, have settled into a similar pattern- 3 deep exhale breaths of 10 seconds each before an apnea. But I wonder if some hook breathing, say, a minute before apnea might build up a reserve of O2 in the body. Just an idea...
Interesting question Glen! :)

You are supposed to be close the 100% saturated with oxygen in your blood and tissues when breathing normally for some time (2~ minutes I am guessing) unless you are in a substantial loss of O2. So I don't see how hook breathing before diving will get you over saturated. I might be wrong though, maybe someone with a pulse/ox want to experiment with this....?

The holds before the dive are supposed to let you accumilate some CO2 back after "over ventilating" (being catious with the term:)). Can also help one to get better in the zone. While repetitive recreational diving I find them excessive though.
Maybe hook breathing before a dive could help to avoid packing blackouts? It might help to reduce the sudden change in blood pressure and the effects of over-ventilating.

Just an idea...

DeeperBlue.com - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing


ISSN 1469-865X | Copyright © 1996 - 2024 deeperblue.net limited.

DeeperBlue.com is the World's Largest Community dedicated to Freediving, Scuba Diving, Ocean Advocacy and Diving Travel.

We've been dedicated to bringing you the freshest news, features and discussions from around the underwater world since 1996.