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Foramen oval permeable and freediving


New Member
May 22, 2009
are there any studies about foramen oval permeable and freediving?
Foramen oval permeable seems to be present in many cases od "undeserved" scuba DCS, migraines after scuba,...
I would be interested in hearing your thoughts about this heart condition and freediving.

Thanks !


Dec 9, 2005
F:Lyon / CZ:Prague
I found a single document referring to cardiac foramen oval in my database: pdf foramen @

I also just checked Google and there are more documents addressing the topic, so I will go through them and add them to the database too:
"foramen ovale" freediving OR breath-hold - Google Search

I guess you will find what you are looking for there too. My uneducated opinion is that the increased susceptibility to DCS would be an issue at freediving too, so if you decide freediving, you should definitely browse through the threads speaking about DCS here on DB, to see how you can reduce the risk. Also the rapid and strong blood pressure changes during and after the Diving Response add a lot of strain on the heart, so you may want to consult your cardiolog to see if it is a manageable risk or not for you.


New Member
May 22, 2009
Thanks for the info trux !
It seems like up to 25% of people may have this heart condition, without knowing it, which is not a problem for normal life.
But for divers and free divers who have had some DCS sympthoms after diving it may be a good idea to get a transesophageal echocardiogram (TEE) to know if they have it.


Jul 1, 2005
Look up PFO too. (P = Patent)

There was a freediving study suggesting that cardiac shunt due to potential PFO was more likely in Freediving because of the repeated pressure changes. I'll have to find the source.

Deano 647

New Member
Jul 29, 2019
This has been a big focus for certain tribes in the tech dive space, but to my memory, it has also thrown up contradictions. As magic sea says, it is found to be present to me extent in around 25% of the population. If it were a condition highly indicative to DCS, then we should find a song correlation in accident data. i.e. When looking at cases of treated DCS, those with PFO should be over represented in the data, but (as I recall) they are not, or at least not to the extent that the 25% of gentlemen pop would suggest. So it's a bigger problem in theory, than it is practice.

Its actually quite a terrifying concept for a deep trimix diver, when I was tech diving I paid out of my own pocket to get tested (negative) but it was not uncommon for divers who tested positive to undertake the rectifying operation using the Amplatzer PFO occluder or similar. - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing


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