In October 2013, JITS France published issue 5 of its magazine, with a remarkable article on blood chokes, and the causes and consequences of losing consciousness.
Our thanks to the authors, Dr SEIFI and Dr MOUDEN, and to JITS France (Raphael LEVY), for allowing us to republish this article on our site exactly as it was written.
Enjoy the read, and learn to tap.
Table des matières
Blood chokes: the causes and consequences of losing consciousness
I have now spent three years working as a doctor at all kinds of sporting events, dealing with injuries that run from the trivial to the potentially fatal. Every so often, I have to wake up a friendly 100 kg lump who forgot to tap.
Ah, the mata leão, that beautiful technique. How many times have I found myself in the middle of it all, hoisting up a pair of 30-kilo legs. Such efficiency.
Brazilian jiu-jitsu history records a saying from the Gracie family according to which chokes are superior to joint locks: break an opponent’s arm and he can still fight; put him to sleep and the victory is total.
Except that he is not asleep: he is unconscious, and the difference is roughly that between kissing Kyra Gracie and kissing André Galvão.
So JITS magazine got in touch with my colleague Dr Mouden and myself, mild-mannered doctors and rather less mild-mannered Brazilian jiu-jitsu practitioners, to clear up how chokes actually work.
So how does a choke work? Is it as bad for you as it looks?
What is a choke?
There are two kinds.
The air choke (for example the Ezekiel choke)
This is compression of the trachea, which sets off a powerful reflex involving coughing and vomiting, as if to clear a foreign body from the airway. Without that reflex, the choke could lead to rupture of the trachea and the complications that come with it.
The blood choke (for example the mata leão, the triangle choke, the cross choke)
In principle, this is vascular compression causing syncope.
Blood supposedly stops reaching the brain.
But what actually happens?
Even though we have some idea of the physical mechanisms behind these blackouts, talking it over with my colleague made me realise that neither of us had any real certainty from our medical school textbooks.
The initial assumption was that Brazilian jiu-jitsu being a young discipline, few doctors had looked into the question.
So we turned to judo, and there, dismay: a search on Pubmed (the database of every existing medical paper) returned few satisfactory results. Judoka apparently do not choke each other much.
But it is not every day you get to combine business with pleasure, so there was only one option left: find out the truth for ourselves, using a doppler ultrasound machine.
An ultrasound scanner is an expensive machine that shows what is happening under the skin in real time. With a doppler mode, it also lets you observe and quantify blood flow, arterial or venous.
After trying it on myself, it was clear the idea worked and would let me advance both science and Brazilian jiu-jitsu. So I went looking for masochistic volunteers.
At the hospital, armed with my nearly €100,000 ultrasound machine, I worked my way through the intensive care unit, choking every nurse willing to play along, and ran fifteen dopplers on the neck vessels of innocent volunteers.
Later, and a few 90 to 100 kg porters further on, I had the beginnings of an answer.
The results are simple:
From the very start of a blood choke, jugular venous flow stops immediately. Blood can no longer leave the brain, and within a few seconds come the headache, then the sensation of blacking out.
If the choke continues, the intracranial hypertension caused by the pooling blood prevents any fresh supply through the carotids, and the brain stops being oxygenated. At that point I let the nurses go, since I still need them to do my job.
I then tried a properly hard choke on the bigger lads at the hospital, and on myself.
This time, not only did venous flow stop, but carotid flow slowed very quickly and the measured diameter of the carotids shrank as well. I released before anything went wrong, because hospitals are not insured against Brazilian jiu-jitsu practitioners.
The mechanism behind loss of consciousness is therefore mixed, both arterial and venous, and it leads to full syncope through cerebral anoxia. Nothing like sleep, since sleep is good for you.
So what are the risks of a choke?
Since 1882 there has not been a single fatal accident in judo competition.
In 1991, Italian doctors ran electroencephalograms to measure brain electrical activity while monitoring changes in cerebral blood flow, choking seven judoka to the point of syncope. The results are fairly reassuring: no lasting damage, and although brain activity does drop, the readings return to normal once the choke is released, within 20 seconds at most according to a comparable study carried out in Frankfurt.
So you might think, reader who only taps at the very last moment, that you are safe. You would be wrong.
There may have been no fatal accidents, but several cases of carotid dissection have been reported.
In plain terms, a tear in the main blood supply to the brain.
The consequences?
At best surgery, at worst death, and most often somewhere in between: motor disability for the rest of your life, though you can also end up unable to speak, or slower than you were, or both.
There are probably also carotid microlesions, the same ones found at autopsy after hanging and in people who play with scarves.
Who knows what they cause in the long run, whether they encourage carotid dissection or strokes?
In 1991, this time in England, a case was reported of a young judoka who, after repeated chokes, was said to have suffered permanent anoxic damage to the left temporal lobe of the brain: in plain language, a softening of the brain, causing memory loss and reduced intelligence.
What should we conclude?
Unfortunately something fairly obvious: repeated cerebral anoxia inevitably has long-term consequences for how our brain works, and therefore for memory, intelligence and motor coordination.
But judoka choke each other less than we do, so we should expect these accidents to be both more frequent and more serious in our sport. To assess the risk properly, you would ideally study serial chokers.
The people best placed to tell us about chokes are the police.
Yes, the police. Not the ones on television, the American ones.
So we have to look at the Americans and their forensic records, from a period when doctors were still allowed to research just about anything.
Through the 1980s, police and prison services routinely used a choke to restrain the bad guys: shime-waza (the cross choke).
And since the land of the stars and stripes likes people who see things through, the choke was held until unconsciousness, for the safety of the good guys.
The outcome was grim: in 1987, 14 deaths were reported, even though the choke had apparently been released right after unconsciousness.
Those same Americans established that a well-executed choke produces full syncope in 10 to 20 seconds at most.
So in judo as in Brazilian jiu-jitsu, the window for tapping is narrow.
When should you tap?
Beyond the feeling that you are about to pass out, you need to know your body and the signals it sends you. The little spots you sometimes see are called phosphenes, and they are a sign of retinal anoxia. If you are starting to see them, your chances of escaping that triangle are slim.
In the same way, the headache comes from intracranial hypertension, and by then it is generally too late as well.
Given that you lose consciousness within 15 seconds on average after these symptoms appear, the margin for tapping is thin.
What happens when I do not tap?
Nobody has studied this seriously yet, so there is no certainty. But ask the various specialists, neurologists, radiologists, forensic pathologists and intensive care doctors, and they all agree on one point:
if there is loss of consciousness, there is cerebral anoxia, and if there is repeated cerebral anoxia across a lifetime, there will be consequences later on.
Every time you lose consciousness, neurons die, and neurons are cells that never regenerate.
One of the main points too often forgotten is that we are not all born equal in the face of disease.
If you are going to develop a neurodegenerative disease at 70 (Alzheimer’s, Parkinson’s, other dementias of old age), with twenty years of Brazilian jiu-jitsu behind you during which you did not tap often enough, you risk developing those diseases earlier, and perhaps more severely.
You might think that tapping keeps you safe. You would be wrong.
In conclusion
One last study by our Italian friends compared brain damage, largely through electroencephalograms, in professional and amateur boxers and judoka.
Carried out in 1998, it found long-term damage only in the professional boxers.
Judo, then, appears to be a combat sport that leaves fewer neurological after-effects than boxing.
But because chokes are far more frequent, Brazilian jiu-jitsu is more dangerous for the brain than judo, and its long-term effects have not yet been studied.
The immediate risk is not zero either.
Every time you lose consciousness, the long-term consequences for your health are real.
So know your limits, and respect your body, your sport and your opponent: sometimes you have to know how to lose with style.
And if your training partner is short on style: release the choke. Once the mechanical obstruction is lifted, blood returns to the brain, and unless you held it far too long, he should come round on his own within 20 seconds.
Nothing stops you from helping him along with the old recipe: raise his feet to speed blood back to the brain and oxygenate it, then season with a few kicks up the backside to… sorry, I meant to stimulate him.
If that does not work? Check that he is still breathing, call someone with a first aid qualification, quickly, and cross your fingers, it can help.
We hope this thorough article has shed some light on how blood chokes work, and on the dangers of tapping too late.