Why strangulation works.

 

Here is some interesting information that many do not know. A strangulation (blood choke) is actually not causing unconsciousness soley from decreasing blood flow, what happens is much more interesting. The human neck has four main arteries that deliver oxygen to the brain, the carotids and the vertebral arteries which run along the spine. The carotid arteries are the ones effected by strangulations while the vertibral arteries still deliver blood unimpeded. When applying a blood choke, you're actually only disrupting a very small amount of actual blood flow, on the order of 10%.

 

So why do people go unconscious when there is still blood flow to the brain? The reason, and also the reason some people are easier or harder to choke lies in nerves that sense blood pressure changes that are concentrated near where the carotids split into two arteries to supply blood to the brain and the face. These clusters of nerves are called Baroreceptors and connect to the carotid sinus nerve. When a strangulation is applied these receptors are tricked into believing there is a massive increase in blood pressure.

 

To counter act this perceived increase in blood pressure the body tries to decrease blood pressure by opening capillaries in the brain. This causes a quick drop on blood pressure in the brain and since the actual blood pressure was not significantly elevated the person passes out, similarly to how if someone with low blood pressure might faint from standing up too quickly.

Even more facinating is that this mechanism is actually used by ER doctors and EMT to palpitate the carotid sinus bariorecpetors to reduce heart rate and blood pressure in emergency situations.

 

When the choke is released the brain believes the pressure has been equalized and constricts the capillaries again restoring normal blood pressure and allowing the person to regain conciousness.

 

So what can we gain from understanding this information?

 

The location of the strsnglehold on the concentration of bariorecpetors is important to produce the fastest most intense reaction from the body

 

Differences in anatomy of someones neck can make the bariorecpetors more or less sensitive making some people go out in 2-3 seconds while others may last 10-15 seconds before passing out.

Adjusting the chokehold causes the bariorecpetors to send pulses of signals and will make it less likely to trigger a drop in blood pressure even if the pressure applied is significant throughout the choke. It's often better to apply constant force to the bariorecpetors than to keep adjusting the choke.