If you are into choking, the bad news is that this is the least safe BDSM activity, it is responsible for the most numbers of death. The good news is that most of those deaths occur when people do it alone. Still, even if you do it as a couple, I strongly advise against it.
Choking, breath play or, more technically, erotic asphyxiation or asphyxiophilia, is used to refer to two very different types of actions. The first involves cutting the air supply to the lungs by choking or blocking the nose and the mouth. The second involves cutting blow flow to the brain, which is usually done by pressing on the carotid arteries. Spoiler alert: the second is much more dangerous than the first.
Straightforward choking, what we see in movies and TV, consists in pressing the neck to constrict the windpipe (https://en.wikipedia.org/wiki/Trachea) to keep air from reaching the lungs. The trachea is a very delicate structure made of cartilage, a tissue similar to bone that also makes our joints. This makes the trachea semi-rigid, so applying pressure on it can deform it permanently. Around the trachea are also the vocal cords and the esophagus. Therefore, this form of choking can produce long-term damage affecting breathing, talking and swallowing. It should never be done, unless it is just fake choking not involving any real pressure on the neck and that does not block breathing.
Of course, it is possible to interrupt the breathing of a bottom partner by other means. One popular one consists of sticking a cock deep into her mouth and then pinching the nose. This has the additional advantage of giving pleasure to the cock-owner and eliciting some interesting gagging reactions in the bottom. However, one thing I don’t understand is why in this type of situation the top is not concerned about having his cock bitten. Sure, any well-behaved submissive will never bite the cock that feeds her, but the body will do all kinds of weird stuff in a life-or-death situation. And breathing is our most basic drive.
OK, so we rule the cock as an instrument of asphyxiation, but there are still many other ways to stop a person from breathing, like putting a pillow or a bag over his nose and mouth. And, yes, this is safer than any of the other possibilities that I am examining [actually, it isn't, because you need to see the face of the bottom to decide when to stop, read the addendum]. The body as a whole can store a good amount of oxygen. There are three main reservoirs: the air still present in your lungs, the hemoglobin (https://en.wikipedia.org/wiki/Hemoglobin) in red blood cells and myoglobin in the muscles. Myoglobin (https://en.wikipedia.org/wiki/Myoglobin)is a protein similar to hemoglobin that is also able to bind oxygen. Cetaceans (whales and dolphins) have large amounts of myoglobin in their muscles that help them hold their breath for long periods of time. Free-divers learn to take advantage of these three reservoirs by different techniques to hold their breath underwater. I can comfortably free-dive for close to one minute, even while moving a lot. I once held my breath for 4 minutes, out of the water and relaxing. The world record in breath-holding is 22 minutes and 22 seconds, after hyperventilating in pure oxygen (https://www.outsideonline.com/1784106/how-long-can-humans-hold-their-breath). But don’t get any ideas. As I said, this is done by trained people able to slow down their heartbeat and using sophisticated techniques to store as much oxygen in their bodies as possible. Importantly, the “air starving” drive that makes you want to breathe is not triggered by the lack of oxygen in your blood but by an excess of CO2. This can lead to dangerous situations (common in free-diving) in which you don’t feel like you need to breathe but are actually about to lose consciousness because there is not enough oxygen reaching your brain. So, if you want to engage in other types of breath play involving hyperventilating and then holding your breath (as I did as a teenager), you may want to learn a thing or two about the physiology involved.
Because of all this, even if asphyxiated to the point of loss of consciousness, most people will resume breathing and regain consciousness without any major consequences. However, this is only when said loss of consciousness doesn’t last more than a few seconds. Any longer than that and you risk having to perform CPR on a person who is unconscious and does not breathe on his own, as it happens with most drowning victims. After all, the centers that control breathing are themselves in the brain, so if the brain is not working they may stop functioning as well. And if the breath is stopped for several minutes there is a real possibility of brain damage.
The carotid arteries (https://en.wikipedia.org/wiki/Commoncarotidartery) form the main supply of blood to the brain. They run quite superficially on both sides of the neck. Cutting them, as we see in Games of Thrones and other gory TV series, will irreversibly lead to death in a matter of seconds. To stay conscious and alive the brain needs a continuous supply of oxygen and glucose from the blood. Neurons are the most finicky cells of the body: if they don’t get their oxygen they immediately throw a temper tantrum and die. Temper tantrum is quite an appropriate figure of speech because a neuron that is starving for oxygen will begin firing a lot of action potentials and releasing its neurotransmitters. The main excitatory neurotransmitter in the brain is the amino acid glutamate, which is also an abundant metabolite. When a neuron dies all of its glutamate is released into its surrounding medium, activating glutamate receptors in its nearby neurons. Too much activation of these glutamate receptors can kill those neurons, too, setting off a chain reaction that produces a wave of cell death spreading through the brain. This is what produces most of the brain damage during a stroke, which happens when a capillary inside the brain is blocked by a blood clot. So, why doesn’t this “wave of death” eventually kill the whole brain? Because there are cells in the brain (astrocytes, microglia and epithelial cells in the capillaries) that are in charge of preventing damage by absorbing glutamate and other neurotoxic substances. Still, considerable harm can be done before these cells manage to bring the situation under control. And, once neurons die, it is almost impossible to replace them.
What does all this have to do with choking? When you block the carotids to induce loss of consciousness and increase pleasure, you are starving neurons of oxygen and may be killing some of them. Keep in mind that you could have a substantial loss of neurons in your brain and not notice anything, because we are not conscious of most of what goes on in our brain. This happens to victims of concussion, who may suffer considerable brain damage without knowing it. The point is: you don’t know what is actually going on in your brain when you drive it close to unconsciousness, just because it is so much fun! Neurons could be dying while you party.
Let me explain why carotid occlusion is much more dangerous than other forms of asphyxiation. The key fact is that when you hold your breath, or when somebody blocks your breathing, there is a big reservoir of oxygen your body can use to stay alive. However, your brain does not have a similar store of oxygen. When you block the carotids, that’s it, your brain starts to run out of oxygen right away. That’s why people die much faster when their necks are cut than when they are strangled. There may be other complications of carotid occlusion, like cholesterol plaques being released from inside the carotids to cause strokes in the brain. But, even if you think you had a safe experience, there may be brain damage that you did not notice. As it happens with concussions (traumatic brain injury), injuries accumulate over time until all of a sudden the symptoms manifest themselves. And then is too damn late to do anything about it.
What I have learned from the comments (Addendum, 2/25/2019)
The main argument put forward by people who disagree with my original post is that choking is routinely practiced in some martial arts and by the police. It turns out that the common wisdom in martial arts is the opposite of what I argued in the original post: that carotid occlusion is more dangerous than blocking air flow into the lungs. In martial arts, what I call carotid occlusion is called “blood choke” while compressing the trachea is called “air choke”, and blood chokes are considered safer than air chokes. Chokeholds in martial arts are done by placing the arms around the neck of the adversary in a position resembling the number 4. This is supposed to compress the carotid arteries but not the trachea. The reason why a blood choke is considered safer than an air choke is that the supply of oxygen to the brain is interrupted and restored very quickly. Conversely, an air choke depletes the blood of oxygen and this takes time to reverse. Furthermore, during an air choke there is an increase of CO2 in the blood that turns into carbonic acid, making it more acidic, which may lead to heart problems. It is further argued in the comments that air chokes have been practiced in martial arts for many years with few recorded accidents.
Blood chokes are used in martial arts and BDSM to achieve entirely different goals. In martial arts the objective is to defeat and subjugate the opponent. In training, since the opponent knows that this is supposed to cause loss of consciousness he may simply go limp once the choke has been completed. And the person doing the choke doesn’t need to cause unconsciousness for more than a few seconds, if at all. On the other hand, in BDSM loss on consciousness is the goal and a fairly long unconsciousness may be desirable to increase orgasms and all the other wonderful things the blood choke is supposed to do. Therefore, unlike in martial arts, there is an incentive to prolong unconsciousness.
Blood chokes are not universally considered safe. From a Wikipedia article on chokeholds (https://en.wikipedia.org/wiki/Chokehold): “Following a series of choking deaths, the Los Angeles Police Department banned chokeholds in 1980, and was soon followed by police departments nationwide. Choking suspects was widely banned by American police departments by the early 1990s, when New York City strengthened the force of an earlier ban on chokeholds.” That supports my idea that the reason why blood chokes are safe in martial arts is because they are used in a light version that leads to only partial or brief loss of consciousness. However, when a blood choke is done for real to completely subjugate a suspect, the risk of death is high enough (https://judoinfo.com/chokes6/) that the police doesn’t want to deal with it.
Most people that practice choking in BDSM do not practice martial arts. In fact, there seem to be a lack of awareness about how long a blood choke can be held without causing brain damage. Worryingly, chokes seem to be practiced by beginners in BDSM or even by vanilla people looking for intense orgasms or a free, legal high. For example, the Choking Game (https://en.wikipedia.org/wiki/Chokinggame#Injuriesand_fatalities) is an activity similar to the one we are discussing here but done for “non-erotic” reasons, just to produce loss of consciousness and euphoria. If it becomes part of the popular culture that choking is safe, fatalities and brain damage will start to increase.
Although I am less sure about my statement that air deprivation is safer than blood chokes, this would be because they are both equally unsafe. Yes, as it was pointed out, using pillows or bags to stop air flow is a bad idea because they will block the view of the bottom’s face, which is essential to know his or her state. However, I do not agree with the idea that increases in CO2 should be the main concern. Blood CO2 increases drive the “air hunger” reflex that would make the bottom struggle and complain, hopefully making the top stop the air deprivation. Lack of oxygen, on the other hand, can be more insidious and produce damage without warning.
Even if it does not cause death, repeated choking to the point of unconsciousness may have cumulative effects leading to brain damage. This was one of the main points I was trying to make in my original post. Neuronal death from anoxia may happens without any symptoms because the brain is very good at compensating for loss of function. This is what happened with traumatic brain injury (TBI), which is now called a “silent epidemic”. Sports like boxing and football cause repeated concussions that have an additive effect. When TBI finally manifest itself is too late to do anything about it. TBI is different from one person to another because different brain regions are affected. It may produce sensory hypersensitivity, chronic pain, motor problems, memory loss and cognitive decline. While the mechanisms of TBI and brain anoxia may be different, they both involve neuronal death, so they may produce similar symptoms. Recreational choking, erotic or otherwise, may lead to another silent epidemic that would remain unknown for many years because the symptoms take a long time to appear and their cause may not be apparent at first.
The vaso-vagal response or reflex syncope (https://en.wikipedia.org/wiki/Reflex_syncope) “is a brief loss of consciousness due to a neurologically induced drop in blood pressure. Before the person passes out there may be sweating, a decreased ability to see, or ringing in the ears. […] Carotid sinus syncope is due to pressure on the carotid sinus in the neck. The underlying mechanism involves the nervous system slowing the heart rate and dilating blood vessels resulting in low blood pressure and therefore not enough blood flow to the brain.” It is been argued that loss of consciousness from blood chokes results from a vaso-vagal response triggered by applying pressure in the carotid arteries, and not by brain anoxia. Therefore, the comment said, blood chokes are not as dangerous as I said in the original post.
Well, first of all, this explanation is still controversial, as explained in this Wikipedia article (https://en.m.wikipedia.org/wiki/Choke-out). Second, even if this is the mechanism behind the blood choke, this doesn’t mean it is safe. Brain anoxia still occurs, even if it is triggered by a decrease in blood pressure. The vagus nerve is one of the main ways the brain control body functions, so repeatedly messing with its activity may have unforeseen health effects. Drops in blood pressure leading to unconsciousness are generally considered a medical condition. Since a slowing of the heart rate is a signature of the vaso-vagal response, a pulse-oximeter could be used to detect its presence. A pulse-oximeter is a medical device that is placed at the end of the finger and that reads in real time the heart rate and the amount of oxygen in the blood. They can be bought online for less than $100. But please note that a pulse-oximeter cannot detect lack of oxygen in the brain during a blood choke, because the concentration of oxygen in the fingers will be normal while it decreases in the brain. In any case, if there is no sweating, vision problems or ringing in the ears, the loss of consciousness is probably not caused by a vaso-vagal response.
Some comments argue that chokes are no different than other BDSM activities that are also dangerous. This argument is fallacious because not all risks are equivalent. Choking is the only BDSM activity in which death is a likely outcome if done wrong. Suspension bondage, blood play and fire play can do a lot of damage if done wrong, but death is still a very unlikely outcome. Humans are notoriously bad at risk assessment. Thinks that scare us a lot, like rock climbing and roller coasters, can be done relatively safely, while others, like driving, are less safe than they feel. Rational risk assessment should involve considering 1) the probability of a bad outcome, 2) how bad that outcome is (i.e. skin burns versus death), 3) the possibility that unforeseen elements affect 1) and 2), for example, when choke is done in addition of other things (bondage, pain, sex, etc.) that complicate the physiology of the bottom and the ability of the top to pay attention.
It was also pointed out that epidemiology does not reveal a huge mortality from chokes. This is also fallacious because assessing the risk of an activity should not be based on examining the mortality relative to the general population, but relative to the number of people practicing that activity. For example, if only 100 people practiced choking and 10 of them died, that would be barely a blip against the whole population in a country, but it would indicate that choking is an extremely dangerous activity (10% mortality rate).
I did several searches in Pubmed to find articles on the damage and safety of chokes, and found little useful information. Perhaps I was using the wrong search terms. Wikipedia and the internet provided some good information, however.
-- This article in Wikipedia titled Chokehold (https://en.wikipedia.org/wiki/Chokehold) makes the following important points: "[…] it is vital to distinguish between air and blood chokes. A hold that simultaneously blocks both the left and right carotid arteries results in cerebral ischemia and loss of consciousness within seconds. If properly applied, the hold produces almost immediate cessation of resistance. However to avoid injury the hold cannot be maintained more than a few seconds. When pressure on the carotids is released, the flow of oxygenated blood resumes immediately and consciousness slowly returns. In contrast, if the airway rather than the carotid arteries is blocked, the subject cannot breathe, but his brain is still perfused with blood and he will remain conscious and may continue to struggle for a minute or more; he will lose consciousness only when the oxygen in the circulating blood is consumed and he collapses from hypoxia. Even if the hold is released at this point, the blood circulating through the brain contains no oxygen, and consequently the subject may not regain consciousness or resume spontaneous breathing.”
--This is an article in Quora evaluating the risk of death from a choke (https://www.quora.com/Could-a-person-die-from-a-sleeper-choke-hold) “It’s completely harmless if the choke is released early, but it can kill if the choke is held tight for 30 seconds or more. The most recent report of a death from a rear naked choke described the deceased as beginning to turn blue in the face after about a minute.”
-- This article discusses the long-term effects of non-consensual strangulation (https://www.domesticshelters.org/articles/health/strangulation-can-leave-long-lasting-injuries).
-- This article describes a stroke resulting from a choke in martial arts (http://www.espn.com/mma/story/_/id/8660482/sean-entin-life-choke)
-- This is a nice short article (https://writersforensicsblog.wordpress.com/2011/07/09/q-and-a-how-long-does-it-take-for-someone-to-die-from-carotid-artery-compression/) about how to describe realistically a murder by choke in a novel, with some useful details on the timing of the process. “The carotids are interconnected in the brain so that in a normal individual compressing a single carotid artery will have little effect. Compressing both can cause a loss of consciousness in 15 to 20 seconds and death in 2 to 4 minutes.”
For the reasons listed above, I consider choking unsafe and I advise against doing it. However, I do recognize that there are a lot of unknowns about its practice. I could not find any research articles that addressed the effect on the brain of repetitive anoxic episodes. In view of this, the rational approach would be to err in the side of caution. Weighing pleasure, on the one hand, against a real possibility of brain damage and even death, on the other, the decision seems quite obvious to me. However, I respect the liberty of everybody to make their own choices. I do practice some risky activities, like rock climbing and free diving, and I would hate it if somebody decided to take away my right to do them. I also think is important that we continue having a conversation about this issue. In particular, if people are going to do it, we need to continue to evaluate its risks and disseminate information about the safest way to do it. What we don’t want is to create a “closet inside the closet” by marginalizing people who do these things.
SOURCE: https://fetlife.com/users/29788/posts/5473993