Pushing the Limits of Extreme Breath-Holding(newyorker.com)
newyorker.com
Pushing the Limits of Extreme Breath-Holding
https://www.newyorker.com/tech/elements/pushing-the-limits-of-extreme-breath-holding
58 comments
I remember holding my breath when watching that movie. Thank you for reminding about it!
I'm a bit confused by the breath-hold where they breathed pure oxygen. The article claims that because they only started with oxygen in their lungs, that is all absorbed and nothing left by the end. But, where does the carbon dioxide go in this case? Your body is producing it, and it normally transitions from the blood into the lungs, to be exhaled. why doesn't it do that if there is only oxygen in there?
Correct me if I'm wrong, but maybe the carbon dioxide you exhale comes from the air you inhale. No air in, no carbon dioxide out.
Your metabolism looks like a combustion process: O2 + hydrocarbons -> CO2 + H2O. The carbon comes from food you ate. If you aren't breathing out CO2, you're either not metabolizing or you're storing the "burned" carbon in an undesirable metabolic byproduct (e.g. lactic acid).
Ok thank you, I also found a short answer[0]. It seems the carbon comes from the conversion of glucose; that is, from food.
[0] http://www.smh.com.au/news/big-questions/we-breath-in-oxygen...
[0] http://www.smh.com.au/news/big-questions/we-breath-in-oxygen...
How is this anything other than dangerous and stupid?
It gets worse:
Competitive diving: During competitions in breath-hold diving, most divers hyperventilate extensively and determine the duration of their breath-hold by means other than the hypercapnic ventilatory drive. Some seem to react to hypoxia via the urge to breathe, while others actively decide to abort the breath-hold when vision starts to falter, described as 'greyout' (personal communication with elite divers).
From:
https://www.diversalertnetwork.org/files/UHMS_DAN_2006_Breat... (Chapter 2, Physiological mechanisms involved in the risk of loss of consciousness during breath-hold diving; pg 27).
Competitive diving: During competitions in breath-hold diving, most divers hyperventilate extensively and determine the duration of their breath-hold by means other than the hypercapnic ventilatory drive. Some seem to react to hypoxia via the urge to breathe, while others actively decide to abort the breath-hold when vision starts to falter, described as 'greyout' (personal communication with elite divers).
From:
https://www.diversalertnetwork.org/files/UHMS_DAN_2006_Breat... (Chapter 2, Physiological mechanisms involved in the risk of loss of consciousness during breath-hold diving; pg 27).
For static apnea, I think they're talking about laying on the surface of a shallow pool with a spotter standing next to them. The free diving--where they do this at depth--is what kills people.
I'm curious, what does the spotter do? How does one know there is a problem? I assume at high levels the competitors are able to lower their metabolism and heart rate, etc. What are alert signs, are they monitoring brain activity?
Generally you lie in the water in a wetsuit for buoyancy. The spotter holds on to you to make sure you don't float out to sea (in our case). They also check on you by prompting you to give an "okay" indication (by lifting a finger every 30 seconds or so).
One danger of being under water is that you can pass out even after you've taken a breath of fresh air, so the spotter also is there to make sure you are good in the few seconds after you come up.
One danger of being under water is that you can pass out even after you've taken a breath of fresh air, so the spotter also is there to make sure you are good in the few seconds after you come up.
What kills people is inadequate security measures, not depth diving vs. static apnea in a pool.
There have been very few (I think only one) deaths during freediving competitions, where protocols are used to guarantee the security of the athletes. Remember that you don't die of a black out, you die of drowning because you inhale water during a black out. As said in another comment, the black out is a protective mechanism when you run low on oxygen, but the breathing reflex is triggered by high CO2. Freedivers train both to sustain low oxygen (by doing long breath holds) and high CO2 (by doing repeats of shorter ones).
Monitoring a static apnea is pretty simple if you just pay close attention: when a black out happens, the diver will usually release a lot of air for instance, and pulling them out of water before they drown is what you do. Then you slap them to wake them up :)
In open water competitions, these days divers are tethered to the dive line, announce their target depth and can't go past it. They also announce an expected dive time which is used to plan the start of the safety divers. These safety divers escort the athlete on the end of the dive up (sometimes, as deep as from 30m), staying close enough to grab them if needed, but never touching them (that would disqualify as assistance). There is also a counter weight in place to bring up everything quickly in case something goes wrong deep. Issues are usually happening close to the surface (let's say in the last 10-15m); deep blackouts are very rare and usually a consequence of other problems like being disoriented if you get a ruptured eardrum.
Recreative freediving is a wonderful activity with very little risk if you just use a buddy system and don't push the limits beyond what both of you can do. It's good for you body and your mind!
There have been very few (I think only one) deaths during freediving competitions, where protocols are used to guarantee the security of the athletes. Remember that you don't die of a black out, you die of drowning because you inhale water during a black out. As said in another comment, the black out is a protective mechanism when you run low on oxygen, but the breathing reflex is triggered by high CO2. Freedivers train both to sustain low oxygen (by doing long breath holds) and high CO2 (by doing repeats of shorter ones).
Monitoring a static apnea is pretty simple if you just pay close attention: when a black out happens, the diver will usually release a lot of air for instance, and pulling them out of water before they drown is what you do. Then you slap them to wake them up :)
In open water competitions, these days divers are tethered to the dive line, announce their target depth and can't go past it. They also announce an expected dive time which is used to plan the start of the safety divers. These safety divers escort the athlete on the end of the dive up (sometimes, as deep as from 30m), staying close enough to grab them if needed, but never touching them (that would disqualify as assistance). There is also a counter weight in place to bring up everything quickly in case something goes wrong deep. Issues are usually happening close to the surface (let's say in the last 10-15m); deep blackouts are very rare and usually a consequence of other problems like being disoriented if you get a ruptured eardrum.
Recreative freediving is a wonderful activity with very little risk if you just use a buddy system and don't push the limits beyond what both of you can do. It's good for you body and your mind!
The problem is that you can't hold your breath if you black out. So if you black out while submerged you're in grave danger, even more so if you're some 30m down (then you're as good as dead).
Even if you have a buddy while this happens and they manage to grab you and drag you out instantly, then start CPR the moment you're on the surface there's nothing guaranteeing you're going to survive.
Even if you have a buddy while this happens and they manage to grab you and drag you out instantly, then start CPR the moment you're on the surface there's nothing guaranteeing you're going to survive.
Actually the rescue procedure is straightforward https://www.deeperblue.com/rescue-procedures-for-freediver-b... so if there is a trained buddy watching your back you gonna be fine.
PS you don't need CPR to recover from blackout.
PS you don't need CPR to recover from blackout.
On a separate note, it is extremely irresponsible to dismiss concerns about getting in difficulty while in the sea as something that can be dealt with easily. Because it can't. The sea can take you in seconds, on a bright sunny day, with calm weather and while you're in full control of your faculties.
I am Greek and so I've grown up next to the sea. I learned to swim around the time I learned to walk. I am a strong swimmer, in other words and very familiar with the sea. And yet, I've almost drowned twice, once when I was grabbed by a strong current and once when I misjudged the strength of the waves and got in the sea to play with them. I'm lucky to be alive, twice over.
It is important to understand that the sea is not your friend. Every time you enter it, you put yourself in mortal danger and that's no exaggeration. Ignoring this puts you into even greater danger.
And, honestly, blacking out while 30m under (or even six, or one) is my own private nightmare. It's the last thing any sane person wants to happen to them. Dismissing it by saying that the rescue procedure is "straightforward" is completely missing the point, that such a situation is very likely to be fatal.
I am Greek and so I've grown up next to the sea. I learned to swim around the time I learned to walk. I am a strong swimmer, in other words and very familiar with the sea. And yet, I've almost drowned twice, once when I was grabbed by a strong current and once when I misjudged the strength of the waves and got in the sea to play with them. I'm lucky to be alive, twice over.
It is important to understand that the sea is not your friend. Every time you enter it, you put yourself in mortal danger and that's no exaggeration. Ignoring this puts you into even greater danger.
And, honestly, blacking out while 30m under (or even six, or one) is my own private nightmare. It's the last thing any sane person wants to happen to them. Dismissing it by saying that the rescue procedure is "straightforward" is completely missing the point, that such a situation is very likely to be fatal.
That link literally says exactly what my comment says. That if you black out on the surface, then, OK, but if you black out in the water then laryngospasm will protect you from inhaling water for a bit (under a minute), but then it will end, at which point you'll inhale water and CPR will become even harder. etc. etc.
Actually, reading a bit about it, laryngospasm does not occur during drowning and so it can't protect you.
The source is "Laryngospasm in breath-hold diving", found in the proceedings of the 2006 Breath-hold diving workshop:
https://www.diversalertnetwork.org/files/UHMS_DAN_2006_Breat...
Vocal cord closure is certainly protective in the initial stages of an immersion accident. This occurs only when the victim is conscious. A person who is unconscious when they enter the water or who loses consciousness in the water will not have protective laryngeal reflexes. If consciousness is lost during static apnea or in an underwater swimming contest, the vocal cords will relax and will not close in response to inhaled water. Similarly a breath-hold diver who loses con sciousness will not develop laryngospasm.
The source is "Laryngospasm in breath-hold diving", found in the proceedings of the 2006 Breath-hold diving workshop:
https://www.diversalertnetwork.org/files/UHMS_DAN_2006_Breat...
Vocal cord closure is certainly protective in the initial stages of an immersion accident. This occurs only when the victim is conscious. A person who is unconscious when they enter the water or who loses consciousness in the water will not have protective laryngeal reflexes. If consciousness is lost during static apnea or in an underwater swimming contest, the vocal cords will relax and will not close in response to inhaled water. Similarly a breath-hold diver who loses con sciousness will not develop laryngospasm.
Sure, but if you have a buddy, a minute is more than enough for a rescue. I did it a couple of times from about 10m and it is a bit stressful but I got free beers in the end :)
Sounds like fun. Maybe drown-and-get-rescued should be introduced as a new sport.
>> There have been very few (I think only one) deaths during freediving competitions, where protocols are used to guarantee the security of the athletes.
Deaths are more frequent than that.
A total of 417 freediving accident cases were captured; 308 fatal and 109 non-fatal. [1]
Of those 417, 18% or ~75 were freediving proper (the rest were snorkelling, spearfishing etc). That was between 2006 and 2011- so about 15 incidents a year, 3/4 of them probably fatal.
Your comment specifically mentions competitions, but that is not really a good measure, because people often dive solo to go after records etc.
In any case, there have been several high-profile deaths in recent years: Audrey Mestre [2], Nicholas Mevoli [3], Loïc Leferme [4], Patrick Musimu [5], Adel Abu Haliqa [6] and of course my personal hero, Natalia Molchanova [7] whom, I should say, is not really gone and is going to come up any time now.
So, you know. Not exactly "very few" deaths.
________________________
[1] http://divewise.org/education/freediver-blackout/statistics/
[2] https://en.wikipedia.org/wiki/Audrey_Mestre
[3] https://en.wikipedia.org/wiki/Nicholas_Mevoli
[4] https://en.wikipedia.org/wiki/Lo%C3%AFc_Leferme
[5] https://en.wikipedia.org/wiki/Patrick_Musimu
[6] https://www.thenational.ae/sport/risks-of-freediving-apparen...
[7] https://en.wikipedia.org/wiki/Natalia_Molchanova
Deaths are more frequent than that.
A total of 417 freediving accident cases were captured; 308 fatal and 109 non-fatal. [1]
Of those 417, 18% or ~75 were freediving proper (the rest were snorkelling, spearfishing etc). That was between 2006 and 2011- so about 15 incidents a year, 3/4 of them probably fatal.
Your comment specifically mentions competitions, but that is not really a good measure, because people often dive solo to go after records etc.
In any case, there have been several high-profile deaths in recent years: Audrey Mestre [2], Nicholas Mevoli [3], Loïc Leferme [4], Patrick Musimu [5], Adel Abu Haliqa [6] and of course my personal hero, Natalia Molchanova [7] whom, I should say, is not really gone and is going to come up any time now.
So, you know. Not exactly "very few" deaths.
________________________
[1] http://divewise.org/education/freediver-blackout/statistics/
[2] https://en.wikipedia.org/wiki/Audrey_Mestre
[3] https://en.wikipedia.org/wiki/Nicholas_Mevoli
[4] https://en.wikipedia.org/wiki/Lo%C3%AFc_Leferme
[5] https://en.wikipedia.org/wiki/Patrick_Musimu
[6] https://www.thenational.ae/sport/risks-of-freediving-apparen...
[7] https://en.wikipedia.org/wiki/Natalia_Molchanova
So you know, only one in competition (Mevoli). I'm very well aware than many die in less well catered environments. I've lost spearfishing friends, and I've been part of search and rescue operations more than once unfortunately. I've also rescued people during freediving training sessions where they felt that they could push their limits because there was adequate safety. But that was always the same story: a little bit deeper, a little longer...
I stand by my point that if you use well known safety measures you reduce the risk level a lot. Specifically from your list: Mestre did not have proper safety (a total shit show from Pipin), Musimu was training alone, Leferme has a inadequate setup for what he was doing, Molchanova was diving alone in >30m (should have been a joke for her, but anything can happen). We'll never know for Adel Abu Haliqa.
I'm not even sure why I argue about that on the internet. I should go diving...
I stand by my point that if you use well known safety measures you reduce the risk level a lot. Specifically from your list: Mestre did not have proper safety (a total shit show from Pipin), Musimu was training alone, Leferme has a inadequate setup for what he was doing, Molchanova was diving alone in >30m (should have been a joke for her, but anything can happen). We'll never know for Adel Abu Haliqa.
I'm not even sure why I argue about that on the internet. I should go diving...
Like I say above, there is no good reason to look at competitions in particular. As there is no good reason for training dives to have worse safety than official events.
Also, the statistics I quoted include competitions. The point is that, safety or no safety, if you black out during a dive, there's a strong chance you'll drown.
>> I'm very well aware than many die in less well catered environments. I've lost spearfishing friends, and I've been part of search and rescue operations more than once unfortunately.
I'd expect anyone with such experience to not take matters of safety lightly, nor dismiss the grave danger of a blackout -with smilies.
Is there some hope that treating the seriousness of the difficulties one can come into during a freedive lightly, could bring more people to the sport? If the only effect of bringing more people to the sport is that more people die, then they're better off staying away.
Also, the statistics I quoted include competitions. The point is that, safety or no safety, if you black out during a dive, there's a strong chance you'll drown.
>> I'm very well aware than many die in less well catered environments. I've lost spearfishing friends, and I've been part of search and rescue operations more than once unfortunately.
I'd expect anyone with such experience to not take matters of safety lightly, nor dismiss the grave danger of a blackout -with smilies.
Is there some hope that treating the seriousness of the difficulties one can come into during a freedive lightly, could bring more people to the sport? If the only effect of bringing more people to the sport is that more people die, then they're better off staying away.
Didn't you read the part where they compare it to any other sport?
“Apnea is not different from many other sports, in the sense that practice at a high level often leads to deleterious impacts on human physiology,” he said. “Think about alpinists going to Mount Everest, climbers, gymnastics, marathon runners—every sport has its drawbacks when performed at the élite level.”
Yes, I thought that was smugly dismissive of the fact that these guys were brain damaged. In more mainstream sports where brain damage is a problem, it at least isn't met with "meh".
For a list of examples, mostly contact sports, see the Wikipedia article on Chronic Traumatic Encephalopathy:
https://en.wikipedia.org/wiki/Chronic_traumatic_encephalopat...
https://en.wikipedia.org/wiki/Chronic_traumatic_encephalopat...
Most documented cases have occurred in athletes involved in contact sports such as American
football, wrestling, ice hockey, rugby, and soccer.[1] Other risk factors include being in the
military, prior domestic violence, and repeated banging of the head.[1]"Traumatic" is the key word there. There are different sorts of brain damage, and traumatic brain damage (the kind from impact) is only one kind. I am not a doctor, but I wouldn't be surprised if brain damage due to hypoxia (low levels of oxygen in the brain) is not considered "traumatic" brain damage, and so wouldn't be on that list.
Mobile friendly quote:
> Most documented cases have occurred in athletes involved in contact sports such as American football, wrestling, ice hockey, rugby, and soccer.[1] Other risk factors include being in the military, prior domestic violence, and repeated banging of the head.[1]
> Most documented cases have occurred in athletes involved in contact sports such as American football, wrestling, ice hockey, rugby, and soccer.[1] Other risk factors include being in the military, prior domestic violence, and repeated banging of the head.[1]
Never had issues with rowing. Just don't compete as a lightweight and you'll be fine. Cycling could be fine but just about everyone gets into traumatic road accidents from time to time.
I did 3m06s in a pool, very much like those apnea competitions. I had a spotter and people around me in case something went wrong.
For me the idea of controlling my body and mind to do such a feat felt like a huge accomplishment. It requires fighting off reflexes, relaxing my muscles and reducing my thoughts to the bare minimum so as to use the least oxygen possible.
Control and determination are tested and it feels great to overcome these things.
I stopped practicing apnea because I didn't have any data on how it could affect my brain negatively but I still am very proud of my accomplishment. Also before I started I couldn't swim a full lap underwater without coming up for air but now I can do it without any problem.
For me the idea of controlling my body and mind to do such a feat felt like a huge accomplishment. It requires fighting off reflexes, relaxing my muscles and reducing my thoughts to the bare minimum so as to use the least oxygen possible.
Control and determination are tested and it feels great to overcome these things.
I stopped practicing apnea because I didn't have any data on how it could affect my brain negatively but I still am very proud of my accomplishment. Also before I started I couldn't swim a full lap underwater without coming up for air but now I can do it without any problem.
It seems Guillaume Néry's career haven't damaged his brain. Of course, this is a single data point, but he has been freediving for twenty years
https://www.deeperblue.com/what-does-a-freedivers-brain-look...
https://www.deeperblue.com/what-does-a-freedivers-brain-look...
I can do around 4m, but I don't try anything longer than that, on purpose. I once did a little short film of mine with the title 3:30 to see if looking at a blank face for that time is interesting enough. It worked but the audience still thought that I was cheating with some film trick. So diving 50m makes a better demo.
used to do this during swim practice. unbelievably relaxing and amazing how far you can swim without a breath with a slow buildup. we used to go up to 4 lengths aka 100m
I recall louis zamperini did similar exerxises to increase his VO2 max
What stroke? Seems like you'd choose a minimal stroke.
Freediving is actually a lot of fun. I freedive with flippers in the summer and I could probably do twice as well in duration and distance if I really tried- but I'm always worried I might pass out underwater and die in the middle of a dive. And that woulnd't be very fun, now would it?
There's lots of recreational activities like that that people start doing because they're very pleasant, then they start getting all competitive about them and take it all to extremes where the only reward is knowing you can beat the competition.
That's kind of sad, really, and completely misses the point of doing something for enjoyment. But I guess it's the prevailing culture. We value being the best at something more than we value life itself.
There's lots of recreational activities like that that people start doing because they're very pleasant, then they start getting all competitive about them and take it all to extremes where the only reward is knowing you can beat the competition.
That's kind of sad, really, and completely misses the point of doing something for enjoyment. But I guess it's the prevailing culture. We value being the best at something more than we value life itself.
"There's lots of recreational activities like that that people start doing because they're very pleasant, then they start getting all competitive about them and take it all to extremes where the only reward is knowing you can beat the competition."
You've just described most people's second to third year of Crossfit.
You've just described most people's second to third year of Crossfit.
You don't find it ironic in that you're judging people for what they find enjoyable and arguing it misses the point of doing something for enjoyment? I receive immense pleasure and enjoyment in improving at things -- something I assume is probably an evolutionary imperative. Bettering ourselves is fun. Competing is fun. Bettering ourselves while competing is absurdly fun.
Fun is one thing. Dangerous is another.
Edit: btw, I think it's fine to "judge" people. My judgement, if that's what it is, can't really affect anyone's life, or actions and they're not even addressed to any particular individual.
You might even say they're actually my, you know- opinions.
Edit: btw, I think it's fine to "judge" people. My judgement, if that's what it is, can't really affect anyone's life, or actions and they're not even addressed to any particular individual.
You might even say they're actually my, you know- opinions.
Sure, but in reality opinions are the one thing we ought scrutinize the most, right? Facts are either true or false, but are unchanging at given any moment in time. Opinions are not necessarily true or false, but can and arguably should constantly change. So perhaps seeing things from anothers eyes might lead you to consider your own opinion in another way. And if not then of course that's also fine. To each their own!
At some point, you have to form an opinion, though. The fact of the matter is that there are dangers associated with freediving, in any form. Whether one considers those dangers as necessary or acceptable, or not, is a matter of opinion.
I mean, there's no way to objectively decide what is acceptable risk. You can choose some arbitrary cutoff point, but it's always going to be an arbitrary cutoff point and nothing else.
And I think it's important to be able to look at facts (limited obviously by our ability to know them for sure) and make a decision about what you think is right to do based on them- and not just regarding risk. Regarding anything. In many issues that we have to deal with in our everyday life there is no cut-and-dried answer, so we just have to exercise our best, well, judgement.
You're right that we must leave such judgements open to re-evaluation, absolutely. That's what debating them on the internets is for :)
I mean, there's no way to objectively decide what is acceptable risk. You can choose some arbitrary cutoff point, but it's always going to be an arbitrary cutoff point and nothing else.
And I think it's important to be able to look at facts (limited obviously by our ability to know them for sure) and make a decision about what you think is right to do based on them- and not just regarding risk. Regarding anything. In many issues that we have to deal with in our everyday life there is no cut-and-dried answer, so we just have to exercise our best, well, judgement.
You're right that we must leave such judgements open to re-evaluation, absolutely. That's what debating them on the internets is for :)
Personally I don't consider it either, it's humans pushing the edge of what is humanly possibly which is something we always do. It's what makes us unique.
That being said, static apnea is actually pretty safe, there is a spotter with the person the whole time. Competition free diving is fairly safe as well, as they have divers stationed at different depths who spot for black out and have spare air.
I don't freedive, but given that I am an avid spearfisher I do apnea training to hit deeper depths and to be able to hunt longer at depth. It is probably the most dangerous of any of the apnea related sports but still relatively safe if you do it correctly, which means having a inflatable buoyancy device, a knife and practicing one down 2 up where one diver goes down, another follows down half way a minute later and one stay at the surface as a spotter. Not only does this provide aid in the event of a blackout but it also provides spotters for sharks.
Another issue with safety is setting a reasonable limit, in static apnea in a pool I can hold for over 5 minutes, but when I am spearfishing I set my clock to 4 minutes, 3 if I am going to 100ft or deeper no matter what is going on, when the time runs out I am surface bound. Once trained it easy to ignore hypoxia and spend another 30 seconds chasing a fish but that can be the difference between life and death. The average human can hold enough oxygen in their lungs to stay conscious for over 6 minutes, the CO2 reflex is what get's them, so if one keeps their dive below 4 minutes as a safety margin the chances of black out are minimized significantly. It becomes dangerous and stupid when people start to throw away those safety mechanisms in a quest to cut corners and push further.
A good example is we where diving a wreck last summer, I was at about 70ft, my cousin was down to 45 2 minutes after I went down. I lined up on a huge Pompano and it started swimming away from me, I pursued for about 20 seconds and it had stopped and turned broadside to me, I needed to close 30 ft. to take the shot but I was already past the 4 minute mark by a few seconds. When you are in that situation it's easy to get tunnel vision on the goal and go for it, but then if the fish moves again you are in this game of just a few more seconds. Anyways, I broke off, flagged my cousin to descendand showed him where the fish was, I went up, took the spotter position, the spotter depended to 45 and I took the spotter position on the surface. My cousin ended up with a prize Pompano and bragging rights, but we all got to ride home on the boat and listen to him go on and on about lining up the shot, at that's the point with proper safety procedures everyone get's to enjoy the ride home.
That being said, static apnea is actually pretty safe, there is a spotter with the person the whole time. Competition free diving is fairly safe as well, as they have divers stationed at different depths who spot for black out and have spare air.
I don't freedive, but given that I am an avid spearfisher I do apnea training to hit deeper depths and to be able to hunt longer at depth. It is probably the most dangerous of any of the apnea related sports but still relatively safe if you do it correctly, which means having a inflatable buoyancy device, a knife and practicing one down 2 up where one diver goes down, another follows down half way a minute later and one stay at the surface as a spotter. Not only does this provide aid in the event of a blackout but it also provides spotters for sharks.
Another issue with safety is setting a reasonable limit, in static apnea in a pool I can hold for over 5 minutes, but when I am spearfishing I set my clock to 4 minutes, 3 if I am going to 100ft or deeper no matter what is going on, when the time runs out I am surface bound. Once trained it easy to ignore hypoxia and spend another 30 seconds chasing a fish but that can be the difference between life and death. The average human can hold enough oxygen in their lungs to stay conscious for over 6 minutes, the CO2 reflex is what get's them, so if one keeps their dive below 4 minutes as a safety margin the chances of black out are minimized significantly. It becomes dangerous and stupid when people start to throw away those safety mechanisms in a quest to cut corners and push further.
A good example is we where diving a wreck last summer, I was at about 70ft, my cousin was down to 45 2 minutes after I went down. I lined up on a huge Pompano and it started swimming away from me, I pursued for about 20 seconds and it had stopped and turned broadside to me, I needed to close 30 ft. to take the shot but I was already past the 4 minute mark by a few seconds. When you are in that situation it's easy to get tunnel vision on the goal and go for it, but then if the fish moves again you are in this game of just a few more seconds. Anyways, I broke off, flagged my cousin to descendand showed him where the fish was, I went up, took the spotter position, the spotter depended to 45 and I took the spotter position on the surface. My cousin ended up with a prize Pompano and bragging rights, but we all got to ride home on the boat and listen to him go on and on about lining up the shot, at that's the point with proper safety procedures everyone get's to enjoy the ride home.
Very informative and good story too.
You mentioned 6 minutes is a typical limit, so 4 gives a good buffer. How much of this buffer do you think is used up by the exertion of descent, hunting and so on?
You mentioned 6 minutes is a typical limit, so 4 gives a good buffer. How much of this buffer do you think is used up by the exertion of descent, hunting and so on?
if you look up freedive fins or watch a spearfishing video you will see they are very different from traditional scuba diving fins, they are designed to magnify small movement. The trick is not to descend fast and vigorous, but rather to lazily peddle down, it takes longer but you end up burning less oxygen and end up with more reserve at depth.
If I where to take a guess I would say if well trained in controlling muscles and heart rate non-static apnea required 15-25% of the oxygen supply that you would have had if you where doing static.
Also the 6 minutes I mentioned has a margin in it as well. I remember reading that totally calm and motionless it's closer to 8 (I have never tried to push past 5, due to the cognitive issue talked about in the article). Most people drown because they panic which can spend it all and get you to black out in as little as 2-3.
That is the really interesting thing about spearfishing, it's requires you to be almost meditative in the face of a bunch of stimuli such as you are in water, you are deep, there are predators attracted to what you are doing and the excitement of the hunt. All those have to be put aside because you biggest issue is time, when it runs out none of it matters so you become hyper focused on time and mastering control of your body to extend you time.
One time I got pinned between the surface and a nosy tiger shark and it struck me after the event, that I never had an oh crap a 14ft tiger is interested in me moment. Instead every thought was about how to engage in a pissing contents with this shark while I conserve energy. It was a fascinating conversation of variables in my mind and almost meditative and robotic. In the end I decided to use the blowfish defense (Compact yourself into a tight ball with eyes on the shark, then when they come in to bump you, you sprawl out in a X formation fast like a squid or a blowfish, predators in the ocean don't like it when something triples in size right as they approach) as it would be one quick burst of energy, instead of poking it with my gun until it got deterred, which would be a death by a thousand prick by slowly eating my time each time I had to volley with it.
If I where to take a guess I would say if well trained in controlling muscles and heart rate non-static apnea required 15-25% of the oxygen supply that you would have had if you where doing static.
Also the 6 minutes I mentioned has a margin in it as well. I remember reading that totally calm and motionless it's closer to 8 (I have never tried to push past 5, due to the cognitive issue talked about in the article). Most people drown because they panic which can spend it all and get you to black out in as little as 2-3.
That is the really interesting thing about spearfishing, it's requires you to be almost meditative in the face of a bunch of stimuli such as you are in water, you are deep, there are predators attracted to what you are doing and the excitement of the hunt. All those have to be put aside because you biggest issue is time, when it runs out none of it matters so you become hyper focused on time and mastering control of your body to extend you time.
One time I got pinned between the surface and a nosy tiger shark and it struck me after the event, that I never had an oh crap a 14ft tiger is interested in me moment. Instead every thought was about how to engage in a pissing contents with this shark while I conserve energy. It was a fascinating conversation of variables in my mind and almost meditative and robotic. In the end I decided to use the blowfish defense (Compact yourself into a tight ball with eyes on the shark, then when they come in to bump you, you sprawl out in a X formation fast like a squid or a blowfish, predators in the ocean don't like it when something triples in size right as they approach) as it would be one quick burst of energy, instead of poking it with my gun until it got deterred, which would be a death by a thousand prick by slowly eating my time each time I had to volley with it.
This is quite interesting -- tangentially related, is anyone aware of studies of the long term effects of sports which include blood chokes (constricting carotids)? These might include Judo, Brazilian Jiu Jitsu, as well as modern MMA and submission grappling. In these cases, there may be plenty of oxygen in the blood, but the blood flow to the brain is being restricted causing loss of consciousness.
One thing I find fascinating is that when you hold your breath long enough and your body is forcing you to breath, your lungs still hold plenty of oxygen. If you exhaled into an empty bag, then inhaled that air back into your lungs, that reflex would be quelled for awhile. Of course after each cycle the O2 content would drop an CO2 would rise and the period of each cycle would get shorter.
matt_wulfeck(5)
The record is held by the first homo sapiens who asphyxiated. Tens of thousands of years and counting!
https://www.popsci.com/scitech/article/2003-06/one-dive-one-...
Although, my first exposure to the topic was a movie called The Big Blue about a free diver pushing himself to and past his limits. Had Jean Reno in it. Just found out it was Luc Besson's movie, too.
https://www.youtube.com/watch?v=82onGmBx9ZM