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?
- 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.
I've seen people react so instinctively to tap-out signals both in martial arts and sometimes outside of it that I've often wondered if you could fight dirty in a real fight by tapping out and then clocking them or at least breaking a hold during that instant where they start to back off.
I think I have used it successfully both in chiropractic and physical therapy contexts. The thing with really top-shelf pain is that if you're not screaming you can't even talk at all. But your hands still work.
These sorts of little reflexive physical communications are super effective.
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
Correct. Usually you need to perform a so called surface protocol after surfacing to show you are still conscious enough. This can be e.g. the removal of your mask, an OK sign and saying "I'm OK". Only if you do that within 15 seconds after surfacing your performance will be valid.
And regarding easy to blackout. Yes and no, I personally avoided it for over 12 years, but then again, I'm no world class athlete and only an enthusiastic hobbyist.
In a documentary about freediving they explained that during competitions there are strict rules and steps for the diver to follow after they emerge from the water surface. Only when followed the dive is considered ok.
This is nuts. I remember reading that Hollywood gave up on underwater filming after near death accidents on sets of The Abyss and especially Waterworld making such productions too risky and expensive so they resorted to VFX faking long underwater scenes after that. Obliviously Cameron didn't get the memo.
James Cameron, maker of The Abyss, probably got the memo. But the memo read “You’re going to need to make much more successful movies before they let you do that again.”
James Cameron has done a huge number of truly amazing things, but he and Ed Harris both nearly drowned during filming of The Abyss. Hopefully he learned from his mistakes.
Yeah not to say some of his knowledge isn’t hard won. Niels Bohr approved.
Looks like in Cameron’s case it was a double fault situation. No alarm on the primary, and the safety person didn’t check his emergency gear. That guy shouldn’t have been punched he should have been fired. And had his license suspended.
What a great movie that is! Who can forget that rat breathing liquid oxygen (or whatever they called it), and the water creature making her face to say hello. It seems sort of forgotten now (perhaps it's just me?) compared to other good films from the same era.
> Who can forget that rat breathing liquid oxygen (or whatever they called it)
I remember seeing the movie as a child with my parents and I was quite appaled by that scene (I hate seeing animal abuse). My father ensured me that was just some kind of effect trickery (I think he believed so himself). Later I found out that it was indeed real.
Whoever wrote the production portion of the wikipedia page for the Abyss did a really good job capturing the sort of bleak "the best way out of this situation is forward" circumstances that arise from taking on a project at the limit of your capability like that.
> how do they check whether the contestant is conscious?
already answered but they'll apply pressure on your hand (or similar) and you need to apply pressure back
> How does the contestant know what his limits are before passing out?
When you hold breath for a long time your body will have muscle contractions. The time that needs to pass for each contraction to happen varies from person to person but it is quite consistent for each person. So free divers can know that they are good up to X contractions which will take after X minutes in certain conditions. The fun part is you can train to experience your first contraction by holding your breath while laying down in bed.
In a group sport like club cycling, it can be everyone's responsibility to make sure that your fellow riders haven't gone either hypoglycemic or into heat stroke. We all watch each other so we can go a bit harder and the people who can still talk keep tabs on everyone else.
I understand that with submersibles and astronauts there's a bit of this going on as well. Everyone is watching everyone else for nitrogen narcosis or hypoxia. Maybe another reason the Navy doesn't like assholes on submarines. How can I tell if you're being a jerk today or we need to check the CO2 sensors? Better to notice Lieutenant Ivers only gets short with people when his blood ox goes a little south.
If you go to solo walking or running, now you are the only one tracking your mental state. Now you have to use your own judgement to try to detect when your judgement is going away. It's... tough. Personally I think it's easier if you've already had practice on team settings. But it's still tough.
Same thing with alcohol. There's a reason bartenders don't serve drunks. No judgement anymore. You should have put the glass down half a drink ago and had some water instead. And I think you can only learn that safely by slowly sidling up to it from the safe side, and have someone to look after you if you go a little fuzzy.
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.
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 imagine a safe version could be made... that would suck all the direct-competition spontaneity out of it. Like "do it on land", or "only in standing-height water and take turns with someone timing and acting as a spotter."
As a teenager I did about 4.5 minutes, as I recall, in a bucket of water. I played the trumpet quite a bit at the time, so I think my capacity was above average. It was a competition and I got first, and the second place fellow was also a trumpet player.
All three of us trumpet players in my middle school band would sit in the back and have breath holding contests while the director was working with other sections or whatever.
In middle school, I was a swimmer on two teams and played trombone. We had a fun little “who can play the longest note” contest…everyone thought I cheated because I lasted about 30 seconds longer than anyone else. Really wasn’t that hard once you find the right position to use minimal air output, since the game wasn’t who could hold the same note, but any note. We regularly trained on the swim team to go as far as possible underwater in an Olympic pool — record on our team was 4 or 5 round-trips if I recall correctly (can’t remember 100%…long ago…but that kid was crazy in both speed and time underwater).
Pretty demoralizing to be labeled a cheater after such hard work expanding lung capacity and efficiency. After that, I wouldn’t even try anymore just so I wouldn’t be called a cheater again. Quit band the next year.
It should given that it works with trumpet (and even voice). I remember listening to some jazz piece on the radio where the DJ, before the song, alerted listeners to the long note that was being held and suggested trying holding your breath for the length of the note (but not—he warned—if you were driving).
It would, which was exactly what I was accused of but wasn’t something I knew how to do…even to this day. I have an idea of the mechanics, I just lack the ability because it has never been something I’ve practiced or developed.
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.
My brother did this in his geometry class and passed out. The nurse called my mom and asked if they should send him home to which she responded, “hell, no!”
From my experience, holding your breath in air and in water are totally different things. I guess, because it is difficult to stop any intake of air when you are in air.
Amazingly so Stephane Mifsud's 11:35 "regular air" WR apnea was set in 2009 and has stood since (at least as far as AIDA is concerned). There was a lot of speculation online back then as it is an extraordinary time and was quite high compared to the previous record. If I recall correctly the hold was performed at his home pool, and he has a lung capacity almost double the average adult male's.
This is a video of the end of Mifsud's 11:35 breath hold: https://www.youtube.com/watch?v=MHPGKb7ipgc . The protocol after the hold is that you have to take off your goggles/mask and noseclip, look at the judges and do a clear hand signal that you're ok. Your chin/face should not touch the water before you get a reply from the judges, in the form of a card. It's nothing short of amazing how clearly he follows protocol given that his brain has been oxygen deprived for more than 11 minutes.
We train for surface protocol to become automatic, so even depraved of oxygen, it becomes a reflex. It does a big difference, you'd be surprised to see how many ppl blackout when surfacing because they exhale too much first :/
Regarding Mifsud, he had a YouTube channel, in French, which is full of information about freediving ! He worked a lot with scientists to understand how his body work and how to reach this world record.
Also he confessed that he does not have spams when holding breath, so it helps a bit.
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.
To add to this, when diving with compressed air most people get woozy and otherwise intoxicated from oxygen around 30 meters from the surface. For some people 25 meters is enough for such symptoms to occur.
Yes, he is. Oxygen toxicity causes seizures, not narcosis, and kicks in at around 1.6 bar of partial pressure (just below 65 m when breathing 21% oxygen as in regular air). PADI uses 1.4 bar to add an extra safety margin.
Oxygen toxicity is really the one thing in recreational diving that will kill you if you do it wrong, though for recreational divers the risk only exists when using enriched air(*).
Fortunately it's trivial to avoid it by only using enriched air where the sea floor is at a safe depth, but you should know the math nevertheless. For example if the sea floor is at 35 m (4.5 bar) you won't enrich air above 1.4/4.5=31% oxygen, probably more like 28%.
Oxygen toxicity is also the (or the main) reason why enriched air must never be stored in white or yellow bottles. If you see yellow you can assume it's 21%, while for any other color you must use an oxymeter before using it. Not doing so can be literally the difference between life and death.
Scuba diving is safe but a lot of the safety is about procedures, as you can see.
(*) Enriching air above 21% oxygen is done to avoid the other issue with nitrogen, which is decompression sickness. It lets you stay longer on the bottom. In other words, enriched air improves the trade-off between bottom time (limited by nitrogen) and maximum depth (limited by oxygen toxicity).
Not with 21% oxygen. 25 meters is 3.5*0.21=0.73 bar of O2 partial pressure, which is within even the strictest limits that apply to rebreathers (1.3 bar).
If you're breathing 100% oxygen for decompression, that's a completely different story and not something a recreational divers will do.
I don't see any thing that supports "when diving with compressed air most people get woozy and otherwise intoxicated from oxygen around 30 meters from the surface".
"Be aware that oxygen toxicity is unpredictable. Divers have experienced convulsions at shallow depths under conditions where most experts would not have expected them to occur."
But that doesn't say what depth, what oxygen % and how often it happens.
It also says that oxygen toxicity is a possibility only above 21% oxygen. In fact, with regular air there are way too many things that have already gone wrong if you are at 65 m depth (or even 50 m).
It's clear from reading the document that convulsions at "shallow depths" refers to the case of breathing 100% oxygen, where 1.5 m difference is the difference between <1.6 bar (safe) and >1.7 bar (absolutely not safe).
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.
The published data for military submarines is the nominal test depth, not the actual design limit. The operational depth may be much deeper but that will be classified.
Recent US submarines all have test depths described by as being in excess of the same few hundred meters. In all likelihood that is a throwaway value. It seems unlikely that they produced generations of submarines that were less capable than their older ones.
> The published data for military submarines is the nominal test depth, not the actual design limit. The operational depth may be much deeper but that will be classified.
We know the actual collapse depth for an older sub: 730m for the USS Thresher (test depth: 400m), in 1963.
Test depths of current generation subs are ~20% higher; pushing them to 700m or so might be plausible, but not much more. Radical hidden capabilities would either require substantial advances in material science or drastically different hull thickness, neither of which is really feasible to hide from adversaries anyway, especially considering how little utility you get from hiding this (compared to e.g. exact capabilities of anti-air interceptors or radar characteristics for bombers/fighters).
>It seems unlikely that they produced generations of submarines that were less capable than their older ones.
i wouldn't be sure. There seems to be no military advantage to deeper so why spend the money. A sub needs to hide, but it can't do any other job when too deep. sinking ships can only be done when near the surface. If the sub can get under a couple thermo layers that is good enough, any deeper is more a party trick than useful.
i'm not in the navy but that is how I read the unclassified information I have access to.
> sinking ships can only be done when near the surface.
Isn't this itself a huge assumption?
Sinking ships via upward facing torpedoes would be a huge tactical advantage at first glance. Less time to detection and deploy countermeasures or evasive maneuvers.
Perhaps, I am wrong in assuming they cannot be fired below a certain depth?
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.
Fun fact: those dive tables were created by the US Navy conducting experiments on its own divers, there was a real human cost to acquire that information.
Scuba diving is great. You don't have to do deep or risky dives to enjoy it. There's a ton of fun in diving around reefs 10m down.
That story is pretty wild. And relatable.
I got myself into a little trouble when I dove the Blue Hole 16 years ago. We were warned pretty heavily how many people have died doing it, so I went in with a healthy level of anxiety. It was my second dive where the dive plan was to go to 40m, which is the limit on regular air.
The descent was surreal. You have the wall of the crater on your side, but everything else is different shades of blue. Past about 10m, there's not really any wildlife to look at, just blue. We descended straight down, going in slow motion. As we went down the blues got gradually darker and deeper.
At probably the high 20s, I started to notice I could really see the surface clearly anymore, and I started to panic. My breath started racing and I started being annoyed by my regulator in my mouth, which is an unnatural feeling to being with. For maybe a minute, I debated whether I should try to get myself under control, or signal my dive instructor I wanted to ascend. Meanwhile, we were still drifting downward. I worried whether nitrogen narcosis might affect my judgment or ability to control my panic.
In the end, I decided not to be a hero. I gave my instructor the thumbs up to ascend, and we went through the orderly process of safety stops. When we got to the top I told her I explained I was feeling panicky (you can't really communicate anything nuanced below the surface), and then I spent the rest of my tank diving the first 10m, which was relaxing, and let me finish the day on a high note.
that comment is a classic and certainly entertaining, but there are multiple levels of safety to prevent something like this from happening, the first of which is the wall of tombstones that greets you when you arrive at that specific dive site. To end up in that situation means to have already made a number of big, big errors.
I remember the Blue Hole as one the best dives I made, and not even the scariest: that prize goes to the time I was in calm waters at 20 meters, and the pressure regulator just failed, leaving me without air from both mouthpieces. And that's why you have a buddy...
I don't think I've ever had anything fail on me diving, but I've been with people who have run out of air (my buddy was constantly using all his up), so having to breathe off someone else's tank isn't uncommon.
As I mentioned in my sibling comment, I did have a scary time on the Blue Hole. I think my other most nervous dives were:
- Pacific dive in Costa Rica in rough seas and surge. We suddenly had visibility drop to near zero when we hit the outflow current of a river. Definitely a lesson in how quick conditions can change.
- Cavern diving in a cenote in Mexico. Nothing weird happened, but we went kinda far in, and I get nervous in overhead environments.
Running out of gas or having to breathe off of someone else's tank is uncommon. Gas planning and monitoring is a fundamental skill that every diver needs to master just to get a basic open water certification. If your buddies aren't able to do this reliably then they need remedial training.
It's good to practice gas sharing as a contingency in case of equipment failure but actually running out is not acceptable.
same, blue hole is notorious because inexperienced divers get pressured into deep dives they haven't trained for by local guides looking to make a quick buck.
my scariest dive was when a 14 year old got separated from the group and thought it would be a good idea to continue his dive for 30 minutes.
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.
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.
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.
How is it even possible to hold breath for 11 minutes? I tried it last week (to avoid inhaling insecticide fumes) and could manage about a minute after trying very hard.
Genetics/randomness must play a significant role. When I was a teenager I could hold my breath for ~1.5 minutes without even trying. With a bit of technique I got it up to 2 minutes with relative ease, I think my max was around 2.5 minutes. The odd thing is that I had no reason to be able to do that, I was pretty out of shape, I didn't play any instruments, or have any other hobbies that would help build that kind of stamina.
On the flip side, out of all the genetic benefits one can get, this might be the lamest one. :(
I'm rather unfit these days - but as a teen I could easily do 3mins at my desk in a class. I can't remember the volume but we did a lung capacity test at school and I had the highest in the class, despite not being sporty or active at all, so I think I have genetics on my side.
I recently tried the 'Wim Hof' method, and was well over 4mins after just a few days practice, and I just went snorkelling and was able to outlast all those I went with. If I was healthier I am sure I could get longer still.
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.
The body doesn't notice a lack of oxygen. Hence the danger of carbon monoxide poisoning or air without o2 etc, as you won't notice o2 lacking. What you notice is co2 buildup, and as long as you keep breathing that's not happening.
When freediving, you can't really avoid it. What you learn however is how to deal with it. Control your diaphragm when it wants to start breathing, as the spasms are wasted energy. It's mostly a mind thing. With simple exercises (co2 tables) and just getting used to the feeling, it took my quite a short time to reach 5 minutes.
One "trick" btw is hyper ventilating. But DONT DO IT! It get rids of lots of co2 in your blood stream / lungs, so it takes a bit longer for the co2 buildup. But you need that buildup. Even though it's painful, that's your only signal as to how you're doing and which you kinda calibrate against. Especially when diving, hyper ventilating before can make it so you suddenly go unconscious before you felt the urge to surface.
Wow, TIL hyperventilating increases the danger! My brothers and I used to compete against each other in swimming pools, and we'd always hyperventilate at the beginning, thinking this 'got the oxygen in'. In any case, it definitely helped. Glad we never got into trouble this way.
My personal record is ~3:30, but I'm pretty sure I could go well past that if we had practiced instead of just competing.
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
And co2 build up isn't even that dangerous, just really uncomfortable. Lack of co2 (from hyperventilating) actually inhibits oxygen uptake and causes dizzyness (up to passing out) that way
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.
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.
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.
I read an article years ago on this. It was interesting. There'a a big psychological component to holding your breath. If I remember correctly, you go through the alphabet and think of an animal that corresponds to each letter. You can also try to think of a person you know for each letter. It's to help you stay calm and focused. The fear and accompanying response will have you out of the water fast. I suspect it's also dangerous. If you start freaking out underwater you're in trouble. I tried applying it while doing Wim Hoff exercises and it helped a lot.
Again I read this in an article. I'm just some guy on the internet. Please don't try without investigating how it's actually done and about any associated dangers.
I'm curious about breath holding and freediving: When you're depriving your body of oxygen for such a long time, do you not risk cells dying, in particular in your brain?
Can you use the oxygen trick to practically extend snorkelling dives?
I used to do a little scuba, but overall didn't like the reliance on often poorly maintained kit. But I do love snorkelling - the lightness and simplicity of it.
Can I breathe pure oxygen for half an hour on the boat and be able to repeatedly snorkel longer?
The desire for breathing comes from CO2, not oxygen. Pre-breathing pure oxygen will likely not have a significant impact on non-trained free divers
Pure oxygen also has its own issues and risks which is part of the training for people who use it. It is not a stretch to call it the opposite of simplicity.
Even though you can do it with pure oxygen, it won't be fun. This is because our breathing reflex activated from the rising carbon dioxide levels - meaning that for a significant portion of the attempt the person was fighting their urge to breathe.
shallow water practice is the best way to gain capacity and confidence, or some sort of winhoff method....sitting on the couch or whatever as it is a simmilar flex that you can drop into any sort of free STATIONARY time, ie not while driving, or on top of anything like that, or before doing a dive, even just blowing your head up, blowing baloons, again within limits, as I believe that there are possible ways to injur yourself doing that, but as an easy to do (very rough) capacity test that can be repeated as often as desired for
almost no cost.
I got to the point where I could swim a full lap(two lengths)in an olympic pool underwater with no trouble, and only a few extra breaths before going, it seemed to be mostly up to following a very moderate and steady stroke.
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.
Just came from 2 week vacation in Togian islands in Indonesia where there is big community spread across various places of these 'sea gypsies'. Their ability to hold breath easily for 5-6 minutes while freediving to 20m depth and chasing fish with harpoons is quite something to see.
True story here. If you're fit you can train this pretty easily. I count my time pushing against the current in Northern CA with free diving fins, a 5mm suit and a speargun and I can manage 2:30. In a warm pool with no current, no sharks and plenty of time to relax I can hit 3:45 and I'm old and out of shape.
When I was in high school I could hold my breath all the way through comfortably numb. None of my friends could even come close. My technique was to breath in and out real fast until I felt tingly.
Which is dangerous and should not be done that way, see my other comment here. Doing it that way masks the signals you get, drastically increasing the chances of blacking out.
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.
So, are "blood scrubbers" a thing? Something like dialysis that could let someone stay under water longer by removing CO2 (combined with novel ways of oxygenating the blood). Could future SCUBA just skip the lung gas exchange part entirely?
The whole history of freediving is an excellent example. E.g Scientists were telling freedivers to not go under 100m, or their lungs would implode under the pressure.
They did it anyway and discovered that our body has a way to protect against this, called blood shift!
I'm not saying you shouldn't listen to scientists though ;)
At least two other Croats broke the same record in the last 11 years (Goran Čolak 23:01 in 2014 and Budimir Šobat 24:37 in 2021). There must be some genetic predisposition.
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.
While that is true, and the full context only makes it worse, the important reminder is that a lot of people have died doing "Wim Hof" breathing before diving. It is not safe to hyperventilate before going into the water, because you are not saturating your blood with any more oxygen (normal breathing accomplishes that), but you are rejecting CO2. Your urgent need to breath is not triggered by low O2 but by high CO2.
So if you hyperventilate and then go under water, you will experience an urgent need to breath after you start to become hypoxic. This has killed people and will kill again. Don't let it be you.
Ah yes the guy who psychologically tortured his own son so much the boy will have massive trauma(s) for rest of his life. Applies also to other people around him.
Really a person we should hold in high regard and listen to. Its not like that person invented cold or coping mechanisms with it.
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?
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.
I've seen people react so instinctively to tap-out signals both in martial arts and sometimes outside of it that I've often wondered if you could fight dirty in a real fight by tapping out and then clocking them or at least breaking a hold during that instant where they start to back off.
I think I have used it successfully both in chiropractic and physical therapy contexts. The thing with really top-shelf pain is that if you're not screaming you can't even talk at all. But your hands still work.
These sorts of little reflexive physical communications are super effective.
yes, i've seen that done in videos of streetfights.
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
Correct. Usually you need to perform a so called surface protocol after surfacing to show you are still conscious enough. This can be e.g. the removal of your mask, an OK sign and saying "I'm OK". Only if you do that within 15 seconds after surfacing your performance will be valid.
And regarding easy to blackout. Yes and no, I personally avoided it for over 12 years, but then again, I'm no world class athlete and only an enthusiastic hobbyist.
In a documentary about freediving they explained that during competitions there are strict rules and steps for the diver to follow after they emerge from the water surface. Only when followed the dive is considered ok.
> Sigourney Weaver trained to hold her breath for 6 and half minutes in her 70s!
That is crazy. It seems Kate Winslet broke Tom Cruise's old record while filming Avatar 2; over 7 minutes(!) in her case:
https://www.indiewire.com/features/general/kate-winslet-beat...
This is nuts. I remember reading that Hollywood gave up on underwater filming after near death accidents on sets of The Abyss and especially Waterworld making such productions too risky and expensive so they resorted to VFX faking long underwater scenes after that. Obliviously Cameron didn't get the memo.
James Cameron, maker of The Abyss, probably got the memo. But the memo read “You’re going to need to make much more successful movies before they let you do that again.”
James Cameron is considered a subject matter expert on deep sea submersibles.
Which a bunch of people found out as soon as they started bitching about why some random Hollywood asshole was commenting on the Oceangate disaster.
If anyone can manage underwater filming safely it's probably him.
He has also confessed that his ulterior motive for making Titanic was to get a studio to pay for an expedition to the Titanic. Which they did.
James Cameron has done a huge number of truly amazing things, but he and Ed Harris both nearly drowned during filming of The Abyss. Hopefully he learned from his mistakes.
[1] https://collider.com/james-cameron-the-abyss-movie-productio...
Yeah not to say some of his knowledge isn’t hard won. Niels Bohr approved.
Looks like in Cameron’s case it was a double fault situation. No alarm on the primary, and the safety person didn’t check his emergency gear. That guy shouldn’t have been punched he should have been fired. And had his license suspended.
Your username is great.
Thankyou! The advantage of having been around a long time: short great usernames were still available!
Jody Foster would like a word..
These actors and actresses don't have to do it, are well compensated for the risk, and likely sign the most air tight waiver that can ever be forged.
> the most air tight waiver
I see what you did there.
> ..near death accidents on sets of The Abyss
What a great movie that is! Who can forget that rat breathing liquid oxygen (or whatever they called it), and the water creature making her face to say hello. It seems sort of forgotten now (perhaps it's just me?) compared to other good films from the same era.
> Who can forget that rat breathing liquid oxygen (or whatever they called it)
I remember seeing the movie as a child with my parents and I was quite appaled by that scene (I hate seeing animal abuse). My father ensured me that was just some kind of effect trickery (I think he believed so himself). Later I found out that it was indeed real.
The liquid is called fluorocarbon.
https://en.wikipedia.org/wiki/Liquid_breathing#Films_and_tel...
> Later I found out that it was indeed real.
Wow, we do learn something new everyday :-)
The effects were so good for their time as well, a semi-forgotten gem that film.
Whoever wrote the production portion of the wikipedia page for the Abyss did a really good job capturing the sort of bleak "the best way out of this situation is forward" circumstances that arise from taking on a project at the limit of your capability like that.
Mary Elizabeth Mastrantonio has a great line: "'The Abyss' was a lot of things. Fun to make was not one of them."
Obliviously [...]
I love that, thanks! :D
I'm making it my new email sign-off.
> how do they check whether the contestant is conscious?
already answered but they'll apply pressure on your hand (or similar) and you need to apply pressure back
> How does the contestant know what his limits are before passing out?
When you hold breath for a long time your body will have muscle contractions. The time that needs to pass for each contraction to happen varies from person to person but it is quite consistent for each person. So free divers can know that they are good up to X contractions which will take after X minutes in certain conditions. The fun part is you can train to experience your first contraction by holding your breath while laying down in bed.
I think this is a self selection bias.
In a group sport like club cycling, it can be everyone's responsibility to make sure that your fellow riders haven't gone either hypoglycemic or into heat stroke. We all watch each other so we can go a bit harder and the people who can still talk keep tabs on everyone else.
I understand that with submersibles and astronauts there's a bit of this going on as well. Everyone is watching everyone else for nitrogen narcosis or hypoxia. Maybe another reason the Navy doesn't like assholes on submarines. How can I tell if you're being a jerk today or we need to check the CO2 sensors? Better to notice Lieutenant Ivers only gets short with people when his blood ox goes a little south.
If you go to solo walking or running, now you are the only one tracking your mental state. Now you have to use your own judgement to try to detect when your judgement is going away. It's... tough. Personally I think it's easier if you've already had practice on team settings. But it's still tough.
Same thing with alcohol. There's a reason bartenders don't serve drunks. No judgement anymore. You should have put the glass down half a drink ago and had some water instead. And I think you can only learn that safely by slowly sidling up to it from the safe side, and have someone to look after you if you go a little fuzzy.
It’s a classic at this point but David Blaine held the record for a while and gave a fantastic TED talk on his process: https://www.ted.com/talks/david_blaine_how_i_held_my_breath_...
Another factor is that it's easier to do it underwater than on land. The mammalian diving reflex is what helps.
That's 29min 4sec after breathing pure oxygen.
The record for regular air is 11min 35sec.
Pretty impressive either way.
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.
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.
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.
https://en.wikipedia.org/wiki/Shallow-water_blackout
I know that now, and I would prevent any kids from breath-holding contests.
But I didn't at 14 years old, nor did my mom or uncle, apparently.
I imagine a safe version could be made... that would suck all the direct-competition spontaneity out of it. Like "do it on land", or "only in standing-height water and take turns with someone timing and acting as a spotter."
Yes, although as another commenter pointed out, being underwater triggers a response in our body that lowers our oxygen consumption.
We did spot for each other, even then, but I don't ever remember anyone thinking they almost passed out or anything.
Funny, I did exactly the same things in my childhood, in my cousin's pool.
But it was on the other side of the pond!
As a teenager I did about 4.5 minutes, as I recall, in a bucket of water. I played the trumpet quite a bit at the time, so I think my capacity was above average. It was a competition and I got first, and the second place fellow was also a trumpet player.
All three of us trumpet players in my middle school band would sit in the back and have breath holding contests while the director was working with other sections or whatever.
In middle school, I was a swimmer on two teams and played trombone. We had a fun little “who can play the longest note” contest…everyone thought I cheated because I lasted about 30 seconds longer than anyone else. Really wasn’t that hard once you find the right position to use minimal air output, since the game wasn’t who could hold the same note, but any note. We regularly trained on the swim team to go as far as possible underwater in an Olympic pool — record on our team was 4 or 5 round-trips if I recall correctly (can’t remember 100%…long ago…but that kid was crazy in both speed and time underwater).
Pretty demoralizing to be labeled a cheater after such hard work expanding lung capacity and efficiency. After that, I wouldn’t even try anymore just so I wouldn’t be called a cheater again. Quit band the next year.
I wonder if circular breathing would work, or works, for trombone. If so you could have held that note "forever" with some training.
It should given that it works with trumpet (and even voice). I remember listening to some jazz piece on the radio where the DJ, before the song, alerted listeners to the long note that was being held and suggested trying holding your breath for the length of the note (but not—he warned—if you were driving).
It would, which was exactly what I was accused of but wasn’t something I knew how to do…even to this day. I have an idea of the mechanics, I just lack the ability because it has never been something I’ve practiced or developed.
I could do 3 minutes pretty easily as a kid, again, sitting in class like another poster. Maybe we had the same boring classes.
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.
Glad I'm not the only one who was bored enough in class to do this.
It was Latin...
My brother did this in his geometry class and passed out. The nurse called my mom and asked if they should send him home to which she responded, “hell, no!”
From my experience, holding your breath in air and in water are totally different things. I guess, because it is difficult to stop any intake of air when you are in air.
¯\_(ツ)_/¯
Amazingly so Stephane Mifsud's 11:35 "regular air" WR apnea was set in 2009 and has stood since (at least as far as AIDA is concerned). There was a lot of speculation online back then as it is an extraordinary time and was quite high compared to the previous record. If I recall correctly the hold was performed at his home pool, and he has a lung capacity almost double the average adult male's.
This is a video of the end of Mifsud's 11:35 breath hold: https://www.youtube.com/watch?v=MHPGKb7ipgc . The protocol after the hold is that you have to take off your goggles/mask and noseclip, look at the judges and do a clear hand signal that you're ok. Your chin/face should not touch the water before you get a reply from the judges, in the form of a card. It's nothing short of amazing how clearly he follows protocol given that his brain has been oxygen deprived for more than 11 minutes.
We train for surface protocol to become automatic, so even depraved of oxygen, it becomes a reflex. It does a big difference, you'd be surprised to see how many ppl blackout when surfacing because they exhale too much first :/
Regarding Mifsud, he had a YouTube channel, in French, which is full of information about freediving ! He worked a lot with scientists to understand how his body work and how to reach this world record. Also he confessed that he does not have spams when holding breath, so it helps a bit.
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?
1: https://en.wikipedia.org/wiki/Oxygen_toxicity
There's definitely nuance here.
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
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.
To add to this, when diving with compressed air most people get woozy and otherwise intoxicated from oxygen around 30 meters from the surface. For some people 25 meters is enough for such symptoms to occur.
Diving on normal air, oxygen toxicity occurs around 60m.
Are you sure you aren't talking about Nitrogen narcosis ('raptures of the deep')?
Yes, he is. Oxygen toxicity causes seizures, not narcosis, and kicks in at around 1.6 bar of partial pressure (just below 65 m when breathing 21% oxygen as in regular air). PADI uses 1.4 bar to add an extra safety margin.
Oxygen toxicity is really the one thing in recreational diving that will kill you if you do it wrong, though for recreational divers the risk only exists when using enriched air(*).
Fortunately it's trivial to avoid it by only using enriched air where the sea floor is at a safe depth, but you should know the math nevertheless. For example if the sea floor is at 35 m (4.5 bar) you won't enrich air above 1.4/4.5=31% oxygen, probably more like 28%.
Oxygen toxicity is also the (or the main) reason why enriched air must never be stored in white or yellow bottles. If you see yellow you can assume it's 21%, while for any other color you must use an oxymeter before using it. Not doing so can be literally the difference between life and death.
Scuba diving is safe but a lot of the safety is about procedures, as you can see.
(*) Enriching air above 21% oxygen is done to avoid the other issue with nitrogen, which is decompression sickness. It lets you stay longer on the bottom. In other words, enriched air improves the trade-off between bottom time (limited by nitrogen) and maximum depth (limited by oxygen toxicity).
Got the symptoms wrong, but oxygen toxicity is also present from 25 meters down.
Not with 21% oxygen. 25 meters is 3.5*0.21=0.73 bar of O2 partial pressure, which is within even the strictest limits that apply to rebreathers (1.3 bar).
If you're breathing 100% oxygen for decompression, that's a completely different story and not something a recreational divers will do.
Have you got a reference for that?
E.g. https://dan.org/health-medicine/health-resources/diseases-co....
I don't see any thing that supports "when diving with compressed air most people get woozy and otherwise intoxicated from oxygen around 30 meters from the surface".
It does say:
"Be aware that oxygen toxicity is unpredictable. Divers have experienced convulsions at shallow depths under conditions where most experts would not have expected them to occur."
But that doesn't say what depth, what oxygen % and how often it happens.
It also says that oxygen toxicity is a possibility only above 21% oxygen. In fact, with regular air there are way too many things that have already gone wrong if you are at 65 m depth (or even 50 m).
It's clear from reading the document that convulsions at "shallow depths" refers to the case of breathing 100% oxygen, where 1.5 m difference is the difference between <1.6 bar (safe) and >1.7 bar (absolutely not safe).
> 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.
The published data for military submarines is the nominal test depth, not the actual design limit. The operational depth may be much deeper but that will be classified.
Recent US submarines all have test depths described by as being in excess of the same few hundred meters. In all likelihood that is a throwaway value. It seems unlikely that they produced generations of submarines that were less capable than their older ones.
> The published data for military submarines is the nominal test depth, not the actual design limit. The operational depth may be much deeper but that will be classified.
We know the actual collapse depth for an older sub: 730m for the USS Thresher (test depth: 400m), in 1963.
Test depths of current generation subs are ~20% higher; pushing them to 700m or so might be plausible, but not much more. Radical hidden capabilities would either require substantial advances in material science or drastically different hull thickness, neither of which is really feasible to hide from adversaries anyway, especially considering how little utility you get from hiding this (compared to e.g. exact capabilities of anti-air interceptors or radar characteristics for bombers/fighters).
https://en.wikipedia.org/wiki/Russian_submarine_Losharik says test depht of 2,000–2,500 meters (6,600–8,200 ft), allegedly happened in 2012 somewhere in the Arctic Ocean.
>It seems unlikely that they produced generations of submarines that were less capable than their older ones.
i wouldn't be sure. There seems to be no military advantage to deeper so why spend the money. A sub needs to hide, but it can't do any other job when too deep. sinking ships can only be done when near the surface. If the sub can get under a couple thermo layers that is good enough, any deeper is more a party trick than useful.
i'm not in the navy but that is how I read the unclassified information I have access to.
> sinking ships can only be done when near the surface.
Isn't this itself a huge assumption?
Sinking ships via upward facing torpedoes would be a huge tactical advantage at first glance. Less time to detection and deploy countermeasures or evasive maneuvers.
Perhaps, I am wrong in assuming they cannot be fired below a certain depth?
just watched: https://www.youtube.com/watch?v=V-mzZXwCn68&t=2s
while these torpedoes are going in the other direction seems like the technology for surviving, functioning and navigating depths definitely exist.
Found the SCUBA diver
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.
Fun fact: those dive tables were created by the US Navy conducting experiments on its own divers, there was a real human cost to acquire that information.
Numerous other training agencies also teach how to use nitrox safely. PADI training isn't specifically required (or even particularly good).
I don't see where the person you replied to claimed there was anything special about PADI.
Never done it, never gonna.
Thank _Neoshade_'s legendary story in a Reddit comment for that - https://www.reddit.com/r/todayilearned/comments/dv99nf/til_t...
With a side helping of Neal Stephenson's Cryptonomicon, and the submarine / treasure hunting arc which describes decompression sickness.
Scuba diving is great. You don't have to do deep or risky dives to enjoy it. There's a ton of fun in diving around reefs 10m down.
That story is pretty wild. And relatable.
I got myself into a little trouble when I dove the Blue Hole 16 years ago. We were warned pretty heavily how many people have died doing it, so I went in with a healthy level of anxiety. It was my second dive where the dive plan was to go to 40m, which is the limit on regular air.
The descent was surreal. You have the wall of the crater on your side, but everything else is different shades of blue. Past about 10m, there's not really any wildlife to look at, just blue. We descended straight down, going in slow motion. As we went down the blues got gradually darker and deeper.
At probably the high 20s, I started to notice I could really see the surface clearly anymore, and I started to panic. My breath started racing and I started being annoyed by my regulator in my mouth, which is an unnatural feeling to being with. For maybe a minute, I debated whether I should try to get myself under control, or signal my dive instructor I wanted to ascend. Meanwhile, we were still drifting downward. I worried whether nitrogen narcosis might affect my judgment or ability to control my panic.
In the end, I decided not to be a hero. I gave my instructor the thumbs up to ascend, and we went through the orderly process of safety stops. When we got to the top I told her I explained I was feeling panicky (you can't really communicate anything nuanced below the surface), and then I spent the rest of my tank diving the first 10m, which was relaxing, and let me finish the day on a high note.
I have over 5000 logged dives and have only suffered DCS once, with the right training SCUBA can be very safe.
that comment is a classic and certainly entertaining, but there are multiple levels of safety to prevent something like this from happening, the first of which is the wall of tombstones that greets you when you arrive at that specific dive site. To end up in that situation means to have already made a number of big, big errors.
I remember the Blue Hole as one the best dives I made, and not even the scariest: that prize goes to the time I was in calm waters at 20 meters, and the pressure regulator just failed, leaving me without air from both mouthpieces. And that's why you have a buddy...
I don't think I've ever had anything fail on me diving, but I've been with people who have run out of air (my buddy was constantly using all his up), so having to breathe off someone else's tank isn't uncommon.
As I mentioned in my sibling comment, I did have a scary time on the Blue Hole. I think my other most nervous dives were:
- Pacific dive in Costa Rica in rough seas and surge. We suddenly had visibility drop to near zero when we hit the outflow current of a river. Definitely a lesson in how quick conditions can change.
- Cavern diving in a cenote in Mexico. Nothing weird happened, but we went kinda far in, and I get nervous in overhead environments.
Running out of gas or having to breathe off of someone else's tank is uncommon. Gas planning and monitoring is a fundamental skill that every diver needs to master just to get a basic open water certification. If your buddies aren't able to do this reliably then they need remedial training.
It's good to practice gas sharing as a contingency in case of equipment failure but actually running out is not acceptable.
Yeah this is no laughing matter, i would refuse to dive with someone who lacks the basic skills to monitor their air responsibly.
same, blue hole is notorious because inexperienced divers get pressured into deep dives they haven't trained for by local guides looking to make a quick buck.
my scariest dive was when a 14 year old got separated from the group and thought it would be a good idea to continue his dive for 30 minutes.
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.
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.
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.
It's dangerous in an enclosed environment, see Apollo 1 for more details.
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.
holding your breath for 11 minutes is asking to see the gates damn
Holding your breath for more than 11 minutes?! That's absolutely crazy, wow.
How is it even possible to hold breath for 11 minutes? I tried it last week (to avoid inhaling insecticide fumes) and could manage about a minute after trying very hard.
Being underwater does make it significantly easier, though the effect is fairly moderate in most humans: https://en.wikipedia.org/wiki/Diving_reflex
Training and genetics.
Genetics/randomness must play a significant role. When I was a teenager I could hold my breath for ~1.5 minutes without even trying. With a bit of technique I got it up to 2 minutes with relative ease, I think my max was around 2.5 minutes. The odd thing is that I had no reason to be able to do that, I was pretty out of shape, I didn't play any instruments, or have any other hobbies that would help build that kind of stamina.
On the flip side, out of all the genetic benefits one can get, this might be the lamest one. :(
I'm rather unfit these days - but as a teen I could easily do 3mins at my desk in a class. I can't remember the volume but we did a lung capacity test at school and I had the highest in the class, despite not being sporty or active at all, so I think I have genetics on my side.
I recently tried the 'Wim Hof' method, and was well over 4mins after just a few days practice, and I just went snorkelling and was able to outlast all those I went with. If I was healthier I am sure I could get longer still.
I would think that high altitude cultures with genes for handling altitude sickness would do well in breath holding contents.
Like why isn't some Peruvian on Nepalese person the record holder? Lakes too cold for recreational swimming maybe?
Incredible!
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.
The body doesn't notice a lack of oxygen. Hence the danger of carbon monoxide poisoning or air without o2 etc, as you won't notice o2 lacking. What you notice is co2 buildup, and as long as you keep breathing that's not happening.
When freediving, you can't really avoid it. What you learn however is how to deal with it. Control your diaphragm when it wants to start breathing, as the spasms are wasted energy. It's mostly a mind thing. With simple exercises (co2 tables) and just getting used to the feeling, it took my quite a short time to reach 5 minutes.
One "trick" btw is hyper ventilating. But DONT DO IT! It get rids of lots of co2 in your blood stream / lungs, so it takes a bit longer for the co2 buildup. But you need that buildup. Even though it's painful, that's your only signal as to how you're doing and which you kinda calibrate against. Especially when diving, hyper ventilating before can make it so you suddenly go unconscious before you felt the urge to surface.
Wow, TIL hyperventilating increases the danger! My brothers and I used to compete against each other in swimming pools, and we'd always hyperventilate at the beginning, thinking this 'got the oxygen in'. In any case, it definitely helped. Glad we never got into trouble this way.
My personal record is ~3:30, but I'm pretty sure I could go well past that if we had practiced instead of just competing.
You can still do it, just never do it alone
We used to hyperventilate before underwater training to extent our time under water
Actually knew someone who didn't make it, after (presumably) using the hyperventilation technique. Such a senseless way to go.
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
And co2 build up isn't even that dangerous, just really uncomfortable. Lack of co2 (from hyperventilating) actually inhibits oxygen uptake and causes dizzyness (up to passing out) that way
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.
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.
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
Were you engaging in a highly scientific study of the deco song whip it?
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%.
What do you mean by “iterating animal names”?
I read an article years ago on this. It was interesting. There'a a big psychological component to holding your breath. If I remember correctly, you go through the alphabet and think of an animal that corresponds to each letter. You can also try to think of a person you know for each letter. It's to help you stay calm and focused. The fear and accompanying response will have you out of the water fast. I suspect it's also dangerous. If you start freaking out underwater you're in trouble. I tried applying it while doing Wim Hoff exercises and it helped a lot.
Again I read this in an article. I'm just some guy on the internet. Please don't try without investigating how it's actually done and about any associated dangers.
I assume a mental strategy to distract yourself from the pain
I'm curious about breath holding and freediving: When you're depriving your body of oxygen for such a long time, do you not risk cells dying, in particular in your brain?
If not, how do we know it's not happening?
It does happen-- which is why we're told to watch out for high CO2 levels in our living spaces and let fresh air in often
A slight increase in inspired CO2 levels might cause some mild symptoms but it won't kill brain cells.
Can you use the oxygen trick to practically extend snorkelling dives?
I used to do a little scuba, but overall didn't like the reliance on often poorly maintained kit. But I do love snorkelling - the lightness and simplicity of it.
Can I breathe pure oxygen for half an hour on the boat and be able to repeatedly snorkel longer?
The desire for breathing comes from CO2, not oxygen. Pre-breathing pure oxygen will likely not have a significant impact on non-trained free divers
Pure oxygen also has its own issues and risks which is part of the training for people who use it. It is not a stretch to call it the opposite of simplicity.
Even though you can do it with pure oxygen, it won't be fun. This is because our breathing reflex activated from the rising carbon dioxide levels - meaning that for a significant portion of the attempt the person was fighting their urge to breathe.
shallow water practice is the best way to gain capacity and confidence, or some sort of winhoff method....sitting on the couch or whatever as it is a simmilar flex that you can drop into any sort of free STATIONARY time, ie not while driving, or on top of anything like that, or before doing a dive, even just blowing your head up, blowing baloons, again within limits, as I believe that there are possible ways to injur yourself doing that, but as an easy to do (very rough) capacity test that can be repeated as often as desired for almost no cost. I got to the point where I could swim a full lap(two lengths)in an olympic pool underwater with no trouble, and only a few extra breaths before going, it seemed to be mostly up to following a very moderate and steady stroke.
Free diving wouldn't be mainstream conscientiousness if it wasn't for possibly one of the greatest movies of all time
https://www.imdb.com/title/tt0095250/
Although you need to watch the non US version for the real ending and good soundtrack !
His spleen must be enormous[1].
[1] https://www.nationalgeographic.com/science/article/bajau-sea...
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!
And injury to it can cause spleen cells to colonize other parts of the abdomen. You could end up with extra spleens!
Just came from 2 week vacation in Togian islands in Indonesia where there is big community spread across various places of these 'sea gypsies'. Their ability to hold breath easily for 5-6 minutes while freediving to 20m depth and chasing fish with harpoons is quite something to see.
Archive-link: https://archive.is/ZR8JL
I wonder if their babies also have enlarged spleens
https://en.wikipedia.org/wiki/Lamarckism
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Most people on this forum could hit 3 minutes with normal air in an afternoon of training.
True story here. If you're fit you can train this pretty easily. I count my time pushing against the current in Northern CA with free diving fins, a 5mm suit and a speargun and I can manage 2:30. In a warm pool with no current, no sharks and plenty of time to relax I can hit 3:45 and I'm old and out of shape.
When I was in high school I could hold my breath all the way through comfortably numb. None of my friends could even come close. My technique was to breath in and out real fast until I felt tingly.
Which is dangerous and should not be done that way, see my other comment here. Doing it that way masks the signals you get, drastically increasing the chances of blacking out.
> “the longest breath held voluntarily under water using oxygen”
Voluntarily is an important point here.
Probably even more important that you have to come out alive
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?
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.
Just lots and lots of training. And probably some good genes to start with.
Huffing O2
So, are "blood scrubbers" a thing? Something like dialysis that could let someone stay under water longer by removing CO2 (combined with novel ways of oxygenating the blood). Could future SCUBA just skip the lung gas exchange part entirely?
It's so crazy that this is even possible. A lot of our old assumptions about the limits of human performance are being rewritten.
The whole history of freediving is an excellent example. E.g Scientists were telling freedivers to not go under 100m, or their lungs would implode under the pressure. They did it anyway and discovered that our body has a way to protect against this, called blood shift!
I'm not saying you shouldn't listen to scientists though ;)
No Guybrush Threepwood joke in here yet?
At least two other Croats broke the same record in the last 11 years (Goran Čolak 23:01 in 2014 and Budimir Šobat 24:37 in 2021). There must be some genetic predisposition.
> There must be some genetic predisposition.
Impossible. It's purely cultural factors, like West African runners or Jewish Nobel prize winners.
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.
It is sobering to see all the related articles underneath that talk about divers who died. Every one of those articles.
I increased my lung capacity using Wim Hof breathing technique and can now hold my breath for 3 minutes.
Same.
Strong recommendation for Wim Hof method if you're undergoing acute stress. Really calms me down.
But stay away from water. Do it on your bed.
Yes, not to be gratuitous but doing Wim Hof breathing before diving can and does lead to drowning.
https://en.wikipedia.org/wiki/Freediving_blackout#Shallow_wa...
It fixed my anxiety.I highly recommend
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.
While that is true, and the full context only makes it worse, the important reminder is that a lot of people have died doing "Wim Hof" breathing before diving. It is not safe to hyperventilate before going into the water, because you are not saturating your blood with any more oxygen (normal breathing accomplishes that), but you are rejecting CO2. Your urgent need to breath is not triggered by low O2 but by high CO2.
So if you hyperventilate and then go under water, you will experience an urgent need to breath after you start to become hypoxic. This has killed people and will kill again. Don't let it be you.
https://en.wikipedia.org/wiki/Freediving_blackout#Shallow_wa...
If it had gone well, like it always did the previous times, then he would have shat out everything in his colon into the fountain.
Yes, really.
"That guy has been cleaning his arse in our fountain again. Let's turn up the pressure to maximum."
So? What does that have to do with his breathing technique?
Also, for anyone needing a bit of background: https://www.reddit.com/r/BecomingTheIceman/comments/e9m2jt/t...
I did not need this reminder.
Ah yes the guy who psychologically tortured his own son so much the boy will have massive trauma(s) for rest of his life. Applies also to other people around him.
Really a person we should hold in high regard and listen to. Its not like that person invented cold or coping mechanisms with it.
You really have to be from the Balkans to do something like this :)
wondering how newborns under respiratory distress can survive hypoxia almost 30' post-birth with 50 and 57% measured SpO2, respectively.
I think it is in some part to do with https://en.wikipedia.org/wiki/Fetal_hemoglobin
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