Could you please explain more about the Ref[2], what does it mean beyond what is in article and how serious is it? "These findings suggest that breath-hold diving training over several years may cause mild, but persistent, short-term memory impairments"

Can you tell more about recreational nitrous oxide and when does the "damage occur"? Is there the same thing with wim hof? (like for example with oximeter 80 Sp02 or below?) I got in wimhof/oxide around 80 Sp02 the interesting thing is I got this feeling with fighting to hold my breath but below 90 I kinda needed to convince myself that I should breath in both cases,

Being a non-expert I can't attempt to speculate on your questions in good faith! All I was suggesting to the parent is that perhaps these articles offer as evidence of damage being done without pushing to the point of unconsciousness? Feedback is definitely welcome by an expert.

Key difference here is that freediving is apnea-induced hypoxia, whereas breathwork is literally the opposite: hyperventilation-induced hyperoxia.

So while interesting as a study, I don't think it offers any insight into the kind of breathwork described in the nature study.

Thank you, this is terrific! Why should tetany be worrisome?

In a medical setting, where I am more familiar with it, tetany is never good. Personally it is also wildly uncomfortable. Perhaps it's fine and somehow pushing through it is part of the "experience", but if I want an altered consciousness I'll stick to a psilocybin-based retreat every 5-10 years and my meditation practice in between :D.

yeah in a medical setting it's usually never good, but afaik it's not the tetany that doctors are worried about about but rather what's causing it.

I did a longer write-up on the physiological effects which you might find interesting: https://docs.google.com/document/d/1RuDv_E9osM1CCFWZMywMru9J...

Is this the same thing you linked upthread? At first glance the URL looks the same.

Yes, sorry for crossposting, just seemed relevant here

No worries!

It is definitely uncomfortable and can produce at least minor injuries; I was wondering if there were other reasons to worry.

So the tetany in breathwork is generally caused by the decreased CO2 concentration causing respiratory alkalosis (ie blood gets more alkaline and has a ph balance of > 7.5), which in turn causes the protein albumin to bind more strongly to calcium and not release it as it's supposed to, and calcium is an important regulator in voltage gated ion channels in neurons.

Long story short, your neurons get just a tad bit more excitable because calcium that usually acts like the bouncer to the hot club is busy snogging albumin. That has very little effect in places in the body, but in motor neurons that control your smallest muscles (face and hand), and in sensory neurons under your skin it does move the needle — that causes the muscles to contract and your skin to feel tingly, both exactly the same cause.

This is the reason people with epilepsy should _NOT_ do breathwork, but for otherwise healthy adults there are no negative long term effects of respiratory alkalosis — a few normal breaths to balance out your co2 and the symptoms will go away.

I've done breathwork for years, and at some point the tetany simply stopped happening and hasn't returned.