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i am a (former) neuroscientist and breathwork facilitator (mostly conscious connected breath) — AMA. the effect of decreased co2 concentration on vasoconstrict

i am a (former) neuroscientist and breathwork facilitator (mostly conscious connected breath) — AMA. the effect of decreased co2 concentration on vasoconstrictions (and also alkalosis-induced tetany, ie your muscles cramping, which happens a lot during breathwork) are well known [1], but i've never seen them quantified in such a clear way. It's cool to see mainstream science give it a closer look! [1] for anyone interested, I wrote an explainer here: https://docs.google.com/document/d/1RuDv_E9osM1CCFWZMywMru9Jn-dw0HwBHXhGUU9osHo/edit?tab=t.0#heading=h.thxogh3ojfl1 https://docs.google.com/document/d/1RuDv_E9osM1CCFWZMywMru9J...

s1artibartfast 1y ago
As a Neuroscientist and breathwork facilitator, do you think there is any harm in intentional apnea (e.g. free diving, static holds, ect)? At what point does cell damage (not necessarily death), kick in? As someone involved in these sports, I operate under the assumption that any damage would kick in after loss of consciousness. For example, if I hold my breath, even for 4 or 5 minutes but dont pass out, that is an indication I am still in the range of safe practice. Anecdotally, I know many people who have spent their lives doing breathholds, and they dont seem any worse for wear. Are there any high quality studies that look at potential brain damage prior to loss of consciousness?
- eigenschwarz 1y ago
  Does this help? I am a physicist with interest in these subjects and have always been wary of breathwork because of tetany and the following studies. What do experts closer to this field make of these? [1] "Brain Damage in Commercial Breath-Hold Divers" https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0105006 https://journals.plos.org/plosone/article?id=10.1371/journal... [2] "Do elite breath-hold divers suffer from mild short-term memory impairments?" https://cdnsciencepub.com/doi/10.1139/apnm-2017-0245 https://cdnsciencepub.com/doi/10.1139/apnm-2017-0245 Ref. [2] is especially concerning to me in pushing in any sort of static apnea training or breathwork: "The time to complete the interference card test was positively correlated with maximal static apnea duration (r = 0.73, p < 0.05) and the number of years of breath-hold diving training (r = 0.79, p < 0.001)."
  - sentimentscan 1y ago
    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,
    - eigenschwarz 1y ago
      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.
    - maebert 1y ago
      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.
  - kragen 1y ago
    Thank you, this is terrific! Why should tetany be worrisome? Edited to add: the second article seems to be about decompression injuries, rather than apnea-induced brain damage?
    - eigenschwarz 1y ago
      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.
elevaet 1y ago
This is a bit off topic, but what do you think about people doing nitrous recreationally? It's always concerned me that people are inhaling close to pure nitrous oxide and holding it in. I've always wondered if this creates damaging low-oxygen conditions without the normal reflexes kicking in, and if this can cause brain/neuronal damage. I believe in medical settings it's delivered in a mixture with O2, but in recreational settings it's usually inhaled directly. I see a lot more talk about the risks of vitamin B12 depletion, and not much talk about O2 deprivation, so not sure if everyone else is crazy or if it's me who is the crazy one.
- Youden 1y ago
  I was being treated with nitrous medically. I asked the anaesthesiologist about how it works recreationally and his answer was that yes, it was mostly just hypoxia.
  - meindnoch 1y ago
    Bullshit. You aren't supposed to be hypoxic when using nitrous. You take a half-breath of air, and then breathe in the n2o.
    - laserlight 1y ago
      So, you get half the oxygen needed and somehow doing so doesn't cause hypoxia, which means “deficiency in the amount of oxygen reaching the tissues”?
      - meindnoch 1y ago
        You don't get half the oxygen. You get as much oxygen as you would during normal calm breathing, which is pretty shallow. Basically, you take a normal breath, which is about 50% lung volume, and then fill your lung up to max capacity with n2o. But you know what? Pulse oximeters are pretty cheap nowadays. Try it for yourself.
        1y ago

s1artibartfast 1y ago

As a Neuroscientist and breathwork facilitator, do you think there is any harm in intentional apnea (e.g. free diving, static holds, ect)? At what point does cell damage (not necessarily death), kick in? As someone involved in these sports, I operate under the assumption that any damage would kick in after loss of consciousness. For example, if I hold my breath, even for 4 or 5 minutes but dont pass out, that is an indication I am still in the range of safe practice. Anecdotally, I know many people who have spent their lives doing breathholds, and they dont seem any worse for wear. Are there any high quality studies that look at potential brain damage prior to loss of consciousness?

eigenschwarz 1y ago
Does this help? I am a physicist with interest in these subjects and have always been wary of breathwork because of tetany and the following studies. What do experts closer to this field make of these? [1] "Brain Damage in Commercial Breath-Hold Divers" https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0105006 https://journals.plos.org/plosone/article?id=10.1371/journal... [2] "Do elite breath-hold divers suffer from mild short-term memory impairments?" https://cdnsciencepub.com/doi/10.1139/apnm-2017-0245 https://cdnsciencepub.com/doi/10.1139/apnm-2017-0245 Ref. [2] is especially concerning to me in pushing in any sort of static apnea training or breathwork: "The time to complete the interference card test was positively correlated with maximal static apnea duration (r = 0.73, p < 0.05) and the number of years of breath-hold diving training (r = 0.79, p < 0.001)."
- sentimentscan 1y ago
  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,
  - eigenschwarz 1y ago
    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.
  - maebert 1y ago
    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.
- kragen 1y ago
  Thank you, this is terrific! Why should tetany be worrisome? Edited to add: the second article seems to be about decompression injuries, rather than apnea-induced brain damage?
  - eigenschwarz 1y ago
    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.

elevaet 1y ago

This is a bit off topic, but what do you think about people doing nitrous recreationally? It's always concerned me that people are inhaling close to pure nitrous oxide and holding it in. I've always wondered if this creates damaging low-oxygen conditions without the normal reflexes kicking in, and if this can cause brain/neuronal damage. I believe in medical settings it's delivered in a mixture with O2, but in recreational settings it's usually inhaled directly. I see a lot more talk about the risks of vitamin B12 depletion, and not much talk about O2 deprivation, so not sure if everyone else is crazy or if it's me who is the crazy one.

Youden 1y ago
I was being treated with nitrous medically. I asked the anaesthesiologist about how it works recreationally and his answer was that yes, it was mostly just hypoxia.
- meindnoch 1y ago
  Bullshit. You aren't supposed to be hypoxic when using nitrous. You take a half-breath of air, and then breathe in the n2o.
  - laserlight 1y ago
    So, you get half the oxygen needed and somehow doing so doesn't cause hypoxia, which means “deficiency in the amount of oxygen reaching the tissues”?
    - meindnoch 1y ago
      You don't get half the oxygen. You get as much oxygen as you would during normal calm breathing, which is pretty shallow. Basically, you take a normal breath, which is about 50% lung volume, and then fill your lung up to max capacity with n2o. But you know what? Pulse oximeters are pretty cheap nowadays. Try it for yourself.
      - 1y ago