Issue 020
December 2006
By Rosi Sexton
Some of the most common submissions used in grappling and mixed martial arts are chokes and strangles. The most common examples in MMA are the guillotine, the rear naked choke and the triangle choke, although there are endless variations, not to mention the many gi chokes of judo and Brazilian Jiu Jitsu.
MECHANISMS OF CHOKING
The objective of a choke is to induce unconsciousness. Typically, in combat sports, the person being choked will tap out or submit before this happens but once in a while a fighter will leave it too late to tap and will “pass out”.
There are two basic mechanisms by which unconsciousness occurs:
1. restriction of air supply to the lungs
2. restriction of blood flow to and from the brain.
Some martial artists make a division in terminology, describing
the former as “chokes” and the latter as “strangles”. While logical, this appears not to be in common usage; the dictionary does not make this distinction, and neither does judo terminology. In this article, to avoid any confusion, I will use the terms “air choke” and “blood choke”.
In practise, the two may look similar. To both the person doing the strangling and the person being strangled, however, there are some significant differences.
AIR CHOKES
An air choke attacks the trachea (windpipe). The trachea is the tube that runs down the front of the neck, allowing air to flow from the nose and mouth into the lungs. The rear side is soft and pliable (as, for example, when you swallow something that is just slightly too large), while the front is tough and reinforced by C-shaped bands of cartilage.
It is relatively difficult to cause unconsciousness with an air choke. To do so, it is necessary to compress the trachea almost completely to prevent the flow of air. This requires a considerable amount of pressure (according to various sources between three and six times as much as a blood choke) and carries a high risk of causing a serious and potentially life threatening injury if the trachea is crushed and cannot reopen or later swells shut due to inflammation.
Fortunately, this rarely becomes an issue. The pressure from an air choke is exceedingly painful, and in competition people will almost invariably tap long before they are close to unconsciousness. This makes them comparatively safe to use in combat sports under appropriate supervision, but much less suitable for use in law enforcement or self defence situations where control and restraint are required.
BLOOD CHOKES
A blood choke works by disrupting the flow of blood to and from the head. The simplified view is that it stops blood getting to the head by shutting off the carotid artery, but this misses some important details.
The first thing to notice is that in addition to the better known carotid arteries, there are two other arteries that go to the brain - the vertebral arteries. It is impossible to shut these off with a choke, as they are protected by bone where they run upwards through the vertebrae in the neck. So when the carotid arteries are pinched off, blood flow to the brain may be reduced but never completely stopped.
This is only half the story, however. Of the veins leaving the head, none are protected in the same way as the vertebral arteries. The main ones are the internal and external jugular veins, which lie in the “carotid triangle” on the side of the neck, near the carotid arteries, and have little protection. It is much easier to squash a vein shut than an artery. Arteries carry blood under high pressure, and have tougher walls; veins on the other hand are under much lower pressure and are less resilient.
So it’s harder to stop blood from getting into the brain, but much easier to stop it leaving. When blood can’t get out of the head, there is a build up of pressure and carbon dioxide in the brain. This is why a person being choked will typically turn red, rather than white. Too much carbon dioxide is as much of a problem for the body as too little oxygen. As the pressure builds up, it becomes even harder for fresh blood to get to the brain and some of the small capillaries in the head start to burst. Many people who are strangled close to unconsciousness will experience bloodshot eyes; this is the place where the ruptured capillaries are most easily visible.
There is also a third effect that may contribute to the effects of
some blood chokes: the carotid sinus reflex. It is highly disputed exactly how much of an effect this has, but is important to understand because it is one of the potential dangers of these techniques and can, in vulnerable individuals, lead to cardiac arrest and sudden death.
High up in the carotid arteries, there are sensors called baroreceptors that monitor the pressure of the blood. These send feedback to the cardio regulatory centre in the brain - the areas that control how fast and hard the heart beats. When the blood pressure in the carotid artery becomes too high, these receptors feed back that information and a signal is sent to the heart which slows it down.
If a choke is applied on or above these baroreceptors in the carotid artery, it can stimulate this response. This can cause the blood pressure to fall rapidly, resulting in unconsciousness. In rare cases, it can cause the heart to slow down to the point where it stops, resulting in cardiac arrest and requiring emergency medical attention. It is this effect that has been implicated in the few deaths from choking that have occurred in judo.
SAFETY
Obviously there is an element of danger to these techniques. In Japan, it is apparently common in judo for athletes to be choked unconscious in training rather than to submit. This naturally raises issues of safety and questions about the potential long-term effects.
The consensus is that being strangled unconscious is considerably less dangerous than a knock out from strikes to the head. Providing the technique is released immediately when the subject becomes unconscious, it appears that there is unlikely to be any lasting damage.
As mentioned above, however, it is worth remembering that there is always the possibility of potentially fatal complications in vulnerable individuals. Extreme caution should be used when applying choking techniques to older individuals or those with a history of cardiovascular problems, including high blood pressure. It is not always possible to tell in advance when someone is at risk, and (rare) cases of cardiac arrest have been reported in young, previously healthy, athletes. Bearing this in mind, it makes sense to avoid choking to unconsciousness during training. In competition, where the risk is highest, qualified medical help should be on hand.
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