Choke science

Experiments with human subjects and animals show the following effects from "choking":

• Unconsciousness is due to lack of oxygen and by the metabolites created in the brain as a result of:
  • Acute cerebral anemia by pressure on: common carotid artery, occipital artery, or jugular vein
  • Shock, reflex action initiated on the receptor organ in the carotid sinus.
• The appearance of flushing of the face because of the disturbances in pressure in the carotid arteries and jugular veins.
  • Decrease blood flow of the face shown by ultrasonic and laser-Doppler blood flow monitoring devices. The mean value is 89.4% with the lowest point in 6 seconds; after release return normal in 13.7 seconds.
  • Decrease oxygen saturation in blood in the helix of the ear by using an ear oximeter. Down from 95 to 86% and reach a minimum of 82% in 2-4 seconds. After regaining consciousness return to 90 to 92%. Sixty percent oxygen saturation in the brain causes unconsciousness.
• Tachycardia hypertension, and mydriasis (dilated pupils) are caused by stimulation of the sympathetic nervous system (vagus nerve). The systemic pressure rises 30-40 mm of Hg. After release the blood pressure returns to normal in 3-4 minutes.
• The peripheral blood vessels are also involved: dilatation of muscle vessels and constriction of skin vessels. In shock, accompanied by unconsciousness, bradycardia and hypotension are observed with dilation of muscle vessels.
• Choking acts as a stressor on the circulatory and hypophysio-adrenocortical system:
  • Decreased blood volume and increased plasma proteins as a result of increased permeability of blood vessels. This is similar to unconscious state following electric shock.
  • No change in the hematocrit value or albumin/globulin.
  • A temporary increase in eosinophiles, then after awakening, there is a decrease in number after 4 hours.
  • The 17-ketosteroids in the urine: 2 hours after recovery, the amount is very much increased then gradually decreased (lasts 6-8 hours).
• The electroencephalogram (EEG): convulsions that appear in the unconscious stage are very similar to those of petit mal of epilepsy. No deleterious effects remained after the use of the choke hold. It is considerable less dangerous than a knockout in boxing. 
  

Sources

Koiwai, E. K. (1999). How Safe is Choking in Judo?

Ohlenkamp, Neil. (1995). Principles of Judo Choking Techniques.  [Online]. Available: http://Judoinfo.com/chokes.htm [2004, December 31 ]. Used with permission.