That's 29min 4sec after breathing pure oxygen.
The record for regular air is 11min 35sec.
Pretty impressive either way.
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.
But I didn't at 14 years old, nor did my mom or uncle, apparently.
We did spot for each other, even then, but I don't ever remember anyone thinking they almost passed out or anything.
But it was on the other side of the pond!
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.
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.
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.
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.
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.
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.
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.
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.
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.
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...
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.
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.
It's good to practice gas sharing as a contingency in case of equipment failure but actually running out is not acceptable.
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.
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.
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.
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.
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?
while these torpedoes are going in the other direction seems like the technology for surviving, functioning and navigating depths definitely exist.
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).
Are you sure you aren't talking about Nitrogen narcosis ('raptures of the deep')?
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).
"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'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).
If you're breathing 100% oxygen for decompression, that's a completely different story and not something a recreational divers will do.
On the flip side, out of all the genetic benefits one can get, this might be the lamest one. :(
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.
Like why isn't some Peruvian on Nepalese person the record holder? Lakes too cold for recreational swimming maybe?