Assuming I understand such a feat even with exposure to pure O2, how does he manage to avoid CO2 build-up? Or, how did he train to retain CO2?
Cells use up O2 and release CO2 into the blood to form carbonic acid (keeping it simple), so the blood pH levels drop, which the body does not care about at all. This is what induces the suffocation reflex.
I wish I had known this while trying to master breathing while swimming freestyle: it is not just their VO2 max, but also their ability to retain CO2. Both aspects need to be trained.
Azrael3000 · 1m ago
You cant avoid co2 build-up, you can only slow it down, main factor here is relaxation. Particularly your brain needs loads of o2, so if you can keep that calm it helps a lot. Obviously a slow metabolism helps as well, so before big static performances fasting is common.
And regarding co2 tolerance, it is a training effect. With training you can withstand much higher levels of co2 without resulting in panic
djtango · 3h ago
Note this is oxygen assisted - the diver breathed pure oxygen and (from the article) can increase available oxygen from 450mL to 3L in doing so.
Still impressive nonetheless and I didn't know that this trick is sometimes used in Hollywood to extend underwater filming time. Avatar 2 comes to mind when I was impressed to find out Sigourney Weaver trained to hold her breath for 6 and half minutes in her 70s!
Coming back to the article, I'm disappointed that the details were sparse - how do they check whether the contestant is conscious? How does the contestant know what his limits are before passing out?
Azrael3000 · 32m ago
To answer your questions:
- A coach / safety will give a signal to the athlete, e.g. pinching of the arm and the athlete will react to it by e.g. lifting a finger.
- Training. You get to know your body and limits very well when training freediving for a longer time. That does not mean that you always avoid blackouts, particularly in competitions they happen but that's what safeties are for. In the end, a free diving competition is one of the safest places to explore your limits.
djtango · 22m ago
For sure - what I find interesting is that passing out is a disqualification (I assume) so there is a fine line between achieving your utmost limit and being disqualified. Which is like most sports but my understanding is that it is quite easy to accidentally slip under so the guy must have incredible body awareness
Another factor is that it's easier to do it underwater than on land. The mammalian diving reflex is what helps.
nfriedly · 3h ago
That's 29min 4sec after breathing pure oxygen.
The record for regular air is 11min 35sec.
Pretty impressive either way.
dhosek · 3h ago
When I was a kid in the 70s, I think the record was somewhere in the neighborhood of 3–5 minutes (maybe seven?) and we used to think that was such a short time that we could do it and then trying in the backyard bucket pools that were endemic in my neighborhood we found that cracking a minute was enough of a challenge.
sejje · 2h ago
At first.
I was also a kid doing this, my cousins and I held ourselves underwater with the ladder rungs in a swimming pool.
At first, yeah a minute was tough. But then it rapidly increased. Unfortunately I don't remember where we topped out, but I think ~3 minutes.
We would also swim pool lengths underwater(but it was a relatively small pool at a condo building). I think I swam 9 once.
They'd let us stay out all night at that pool, it was great. Florida summers don't really get chilly.
Terr_ · 1h ago
Such contests are more dangerous than they first appear: Many kids will grasp the obvious trick of hyperventilating to improve their time, but that can lead to abrupt unconsciousness and drowning.
I could do 3 minutes pretty easily as a kid, again, sitting in class like another poster. Maybe we had the same boring classes.
rebuilder · 36m ago
I once held my breath for 5 minutes when I was 14, sitting in class. I suppose it’s possible I was accidentally breathing through my nose a little as I wasn’t underwater.
rajamaka · 16m ago
Glad I'm not the only one who was bored enough in class to do this.
mdaniel · 3h ago
I somehow thought that pure oxygen was poisonous[1], and it needed to be a nitrogen mix. I mean, I guess this stunt demonstrates that I'm clearly mistaken, or that the nuance is in the pressures involed?
Pure oxygen puts oxidative stress on your cells. Your body can handle that just fine at 1 atm, but at elevated partial pressures the increased concentration will (quickly) overwhelm your cellular mechanics.
Underwater, the maximum operating depth for 100% O2 is 6 meters (20 feet) - which isn't very much at all. If you dive any deeper than that, you'll be at severe risk for a seizure and unconsciousness, and likely drown. (I'm simplifying, see [1].)
Which is why you don't go diving with pure O2.
However, in this case the freediver wouldn't be breathing compressed O2 gas underwater. They would've been breathing it at the surface, at 1 atm.
Oxygen weathering is a primary constraint on life on Earth, and every carbon-hydrogen based organism in the past 2.5 billion years has had to develop biochemical coping mechanisms for this toxic gas that wants to react with carbon and with hydrogen; It is harnessing this reaction ("respiration") with biologically mediated processes and modulating it to specific rates that permits us life.
For humans, acute breathing gas toxicity only happens in a high pressure environment.
Air approximates an 80/20 nitrogen-oxygen mix. Atmospheric pressure is 14.7psi.
The 120psi air compressor in your auto body shop is equivalent to a dive only 81 meters deep. SCUBA divers and later saturation divers have probed the various limits of the human cardiopulmonary system using very specialized gas blends all the way down to 700 meters. Too much oxygen partial pressure causes all the symptoms you see listed, and higher partial pressures cause symptoms to appear faster.
> The curves show typical decrement in lung vital capacity when breathing oxygen. Lambertsen concluded in 1987 that 0.5 bar (50 kPa) could be tolerated indefinitely.
This means you could breath 80/20 nitrox at 2.5 bar, or 37 psi, or 25 meters depth, "indefinitely" in the sense of hours or days.
PS: Chronic use of 100% oxygen at atmospheric pressure causes other types of toxicity. Some of the oxidative damage therein, accumulated over the years at a normal 20%, probably directly analogizes parts of the human aging process. Other types of oxidative damage probably work faster than proportional exposure. We only start to notice damage like this in people with impaired lung function who rely on an artificial supply of oxygen boosted to beyond an 80/20 ratio, to breath.
actinium226 · 47m ago
> all the way down to 700 meters.
700m! That's wild, I mean nuclear submarine crush depths are at like 400-500m? I get that it's not like you can compare a hard steel tube with a human body but regardless, it's wild.
thrown-0825 · 1h ago
Found the SCUBA diver
SOLAR_FIELDS · 1h ago
Indeed, the grandparent post is a pretty good summary of the takeaways you get from taking PADI’s enriched air nitrox course (which is a requirement if you ever want to dive with enriched air).
In the olden days this was tracked manually (the ratio of your depth to percentage of air and time under water) via so called “dive tables”. The purpose and output of the dive table is to determine the safe amount of time you could dive at a certain depth without risking narcosis.
As this is a sliding window based on multiple variables - and you are very rarely maintaining a constant depth as you dive - it’s of course annoying and less accurate to hand calculate this. Modern dive computers just seamlessly calculate it all for you nowadays.
Retric · 2h ago
It’s really several factors. Supplemental oxygen is common for people with diminished lung capacity, carbon monoxide exposure etc. However long term it’s not a good idea for healthy people. https://en.wikipedia.org/wiki/Oxygen_therapy
At low pressure pure oxygen can similarly be beneficial, mountain climbers eventually need supplemental oxygen for Mount Everest though a few have made the trip without it they can’t stay at that altitude indefinitely. It can even help on airplane flights as commercial airlines don’t set things to sea level.
Where healthy people run into issues is when partial pressures get well over 100% at sea level. Part of the issue is people adjust their breathing based on carbon dioxide not oxygen levels. So at say 10 atmospheres at normal atmospheric mixtures your breathing the equivalent of 210%, but you don’t slow down enough to compensate. Thus why divers care so much about gas mixtures, however people with diminished lung capacity are going to encounter issues at different levels than normal divers.
teraflop · 3h ago
Yes, partial pressure is what matters. Normal air at 1 bar (1 atmosphere) contains about 0.2 bar of O2. Pure oxygen at sea level is 1 bar of O2.
The article you linked has a graph showing that 0.5 bar of O2 can be tolerated pretty much indefinitely, and it takes hours for significant toxicity to show up at 1 bar. Higher partial pressures cause much faster symptoms.
QuinnyPig · 3h ago
Yes. It’s under pressure that oxygen toxicity becomes an issue. It’s why you’ve gotta pay attention to your depth when diving with enriched air.
greesil · 3h ago
It's dangerous in an enclosed environment, see Apollo 1 for more details.
TylerE · 3h ago
It is, kinda sorta, but at 1 atm you need to be breathing pure o2 for ~24 hrs before its meaningful (and longer than that before treatment is anything beyond "stop breathing pure o2". The dose isn't even cumulative. Just being on room air for 20-30 minutes resets the clock.
throwmeaway222 · 2h ago
holding your breath for 11 minutes is asking to see the gates damn
stavros · 3h ago
Holding your breath for more than 11 minutes?! That's absolutely crazy, wow.
OsrsNeedsf2P · 3h ago
I briefly got into breath holding. It's impressive how long you can go with simple techniques; slow stretches with lungs full of air, packing, and iterating animal names.
But I started to question the brain damage and couldn't find good science to confirm it either way.
edwardsdl · 1h ago
What do you mean by “iterating animal names”?
TylerE · 3h ago
Did you ever try wearing a pulseox and seeing what your sat looked like? As long as sats aren't ever dipping below (NOT medical advice, but I'm being conservative here), say, 90%, brain damage is very remote. Plenty of COPD patients walking around with sats in the 80s, or even 70s.
But as someone with bad lungs...yeah, you only get one set and most meds/treatments are partial symptom relief at best.
minitech · 7m ago
Hey, I happened to try this recently when I was holding my breath for another reason! It hit 70% or a little lower by the end*, but that was after having exhaled for a while. I do wonder what effect that kind of thing can have, even minor.
* sensor accuracy not guaranteed
Nicholas_C · 1h ago
Not the OP but I used to do breathe hold training for surfing and bought a pulse oximeter. I don’t think I ever got below 90%.
scabby · 47m ago
> “the longest breath held voluntarily under water using oxygen”
And he should avoid high impact sports and never get into a motorcycle accident.
Spleens are big bags of blood, and trauma to them, especially when enlarged or inflamed, can be fatal. It's one of the easiest accidental ways to bleed out.
Impressive hack and performance, though!
downrightmike · 3h ago
And injury to it can cause spleen cells to colonize other parts of the abdomen. You could end up with extra spleens!
darkerside · 1h ago
I wonder if their babies also have enlarged spleens
andyferris · 1h ago
> Programs should be valid as they are typed
If I take that to the extreme so that the program is almost always syntactically valud - not only should we want python's lack of character to end a block, but also an array, tuple, dict, etc. I'm not sure - something like this?
function f(x):
return array:
1,
2,
3
nradov · 3h ago
It's so crazy that this is even possible. A lot of our old assumptions about the limits of human performance are being rewritten.
stevage · 2h ago
I'm surprised they don't make any mention of how dangerous this sport can be. Particularly if you are taking steps to avoid CO2 build-up, which is the thing that triggers the suffocation reflex.
robocat · 3h ago
I wonder if the diver used any assistance to improve their oxygen capacity?
Adding extra red blood cells into our body?
Increasing the oxygen capacity of existing cells?
Is there anything we can eat/drink that would soak up excess carbon dioxide?
jfengel · 2h ago
Just lots and lots of training. And probably some good genes to start with.
TylerE · 2h ago
The funny thing is the co2 isn't doing much in the short term except make you feel completely terrible, because that's how most mammals evolved not dying in caves and underground tunnels. You can't feel low o2 (well, you can with training like aviators get) so you feel excess co2 instead.
bobmcnamara · 3h ago
Huffing O2
just-the-wrk · 1h ago
Most people on this forum could hit 3 minutes with normal air in an afternoon of training.
MaxPock · 1h ago
I increased my lung capacity using Wim Hof breathing technique and can now hold my breath for 3 minutes.
chneu · 1h ago
reminder that wim hof blew his intestines apart because he was using a public fountain to blow water up his own ass.
he'd done it plenty of times before, he said, but they recently changed the water pressure and he wasn't aware.
awesome_dude · 3h ago
Free diving wouldn't be mainstream conscientiousness if it wasn't for possibly one of the greatest movies of all time
Assuming I understand such a feat even with exposure to pure O2, how does he manage to avoid CO2 build-up? Or, how did he train to retain CO2?
Cells use up O2 and release CO2 into the blood to form carbonic acid (keeping it simple), so the blood pH levels drop, which the body does not care about at all. This is what induces the suffocation reflex.
I wish I had known this while trying to master breathing while swimming freestyle: it is not just their VO2 max, but also their ability to retain CO2. Both aspects need to be trained.
And regarding co2 tolerance, it is a training effect. With training you can withstand much higher levels of co2 without resulting in panic
Still impressive nonetheless and I didn't know that this trick is sometimes used in Hollywood to extend underwater filming time. Avatar 2 comes to mind when I was impressed to find out Sigourney Weaver trained to hold her breath for 6 and half minutes in her 70s!
Coming back to the article, I'm disappointed that the details were sparse - how do they check whether the contestant is conscious? How does the contestant know what his limits are before passing out?
- A coach / safety will give a signal to the athlete, e.g. pinching of the arm and the athlete will react to it by e.g. lifting a finger.
- Training. You get to know your body and limits very well when training freediving for a longer time. That does not mean that you always avoid blackouts, particularly in competitions they happen but that's what safeties are for. In the end, a free diving competition is one of the safest places to explore your limits.
The record for regular air is 11min 35sec.
Pretty impressive either way.
I was also a kid doing this, my cousins and I held ourselves underwater with the ladder rungs in a swimming pool.
At first, yeah a minute was tough. But then it rapidly increased. Unfortunately I don't remember where we topped out, but I think ~3 minutes.
We would also swim pool lengths underwater(but it was a relatively small pool at a condo building). I think I swam 9 once.
They'd let us stay out all night at that pool, it was great. Florida summers don't really get chilly.
https://en.wikipedia.org/wiki/Shallow-water_blackout
1: https://en.wikipedia.org/wiki/Oxygen_toxicity
Pure oxygen puts oxidative stress on your cells. Your body can handle that just fine at 1 atm, but at elevated partial pressures the increased concentration will (quickly) overwhelm your cellular mechanics.
Underwater, the maximum operating depth for 100% O2 is 6 meters (20 feet) - which isn't very much at all. If you dive any deeper than that, you'll be at severe risk for a seizure and unconsciousness, and likely drown. (I'm simplifying, see [1].)
Which is why you don't go diving with pure O2.
However, in this case the freediver wouldn't be breathing compressed O2 gas underwater. They would've been breathing it at the surface, at 1 atm.
[1]: https://en.wikipedia.org/wiki/Maximum_operating_depth
For humans, acute breathing gas toxicity only happens in a high pressure environment.
Air approximates an 80/20 nitrogen-oxygen mix. Atmospheric pressure is 14.7psi.
The 120psi air compressor in your auto body shop is equivalent to a dive only 81 meters deep. SCUBA divers and later saturation divers have probed the various limits of the human cardiopulmonary system using very specialized gas blends all the way down to 700 meters. Too much oxygen partial pressure causes all the symptoms you see listed, and higher partial pressures cause symptoms to appear faster.
> The curves show typical decrement in lung vital capacity when breathing oxygen. Lambertsen concluded in 1987 that 0.5 bar (50 kPa) could be tolerated indefinitely.
This means you could breath 80/20 nitrox at 2.5 bar, or 37 psi, or 25 meters depth, "indefinitely" in the sense of hours or days.
PS: Chronic use of 100% oxygen at atmospheric pressure causes other types of toxicity. Some of the oxidative damage therein, accumulated over the years at a normal 20%, probably directly analogizes parts of the human aging process. Other types of oxidative damage probably work faster than proportional exposure. We only start to notice damage like this in people with impaired lung function who rely on an artificial supply of oxygen boosted to beyond an 80/20 ratio, to breath.
700m! That's wild, I mean nuclear submarine crush depths are at like 400-500m? I get that it's not like you can compare a hard steel tube with a human body but regardless, it's wild.
In the olden days this was tracked manually (the ratio of your depth to percentage of air and time under water) via so called “dive tables”. The purpose and output of the dive table is to determine the safe amount of time you could dive at a certain depth without risking narcosis.
As this is a sliding window based on multiple variables - and you are very rarely maintaining a constant depth as you dive - it’s of course annoying and less accurate to hand calculate this. Modern dive computers just seamlessly calculate it all for you nowadays.
At low pressure pure oxygen can similarly be beneficial, mountain climbers eventually need supplemental oxygen for Mount Everest though a few have made the trip without it they can’t stay at that altitude indefinitely. It can even help on airplane flights as commercial airlines don’t set things to sea level.
Where healthy people run into issues is when partial pressures get well over 100% at sea level. Part of the issue is people adjust their breathing based on carbon dioxide not oxygen levels. So at say 10 atmospheres at normal atmospheric mixtures your breathing the equivalent of 210%, but you don’t slow down enough to compensate. Thus why divers care so much about gas mixtures, however people with diminished lung capacity are going to encounter issues at different levels than normal divers.
The article you linked has a graph showing that 0.5 bar of O2 can be tolerated pretty much indefinitely, and it takes hours for significant toxicity to show up at 1 bar. Higher partial pressures cause much faster symptoms.
But I started to question the brain damage and couldn't find good science to confirm it either way.
But as someone with bad lungs...yeah, you only get one set and most meds/treatments are partial symptom relief at best.
* sensor accuracy not guaranteed
Voluntarily is an important point here.
[1] https://www.nationalgeographic.com/science/article/bajau-sea...
Spleens are big bags of blood, and trauma to them, especially when enlarged or inflamed, can be fatal. It's one of the easiest accidental ways to bleed out.
Impressive hack and performance, though!
If I take that to the extreme so that the program is almost always syntactically valud - not only should we want python's lack of character to end a block, but also an array, tuple, dict, etc. I'm not sure - something like this?
Adding extra red blood cells into our body?
Increasing the oxygen capacity of existing cells?
Is there anything we can eat/drink that would soak up excess carbon dioxide?
he'd done it plenty of times before, he said, but they recently changed the water pressure and he wasn't aware.
https://www.imdb.com/title/tt0095250/