ischemia and a temporary hypoxic condition in the brain. A well-applied blood choke may lead to unconsciousness in 10–20 seconds. Injury or death is plausible if the arteries remain constricted for more than 20 seconds. Compared to strangulation with the hands, properly applied blood chokes require little physical strength. Use in combat sports Most chokeholds featured in combat sports and martial arts are blood chokes, although some air chokes or combinations occur as well. Blood chokes, especially the rear naked choke, triangle chokes, or gi chokes, are commonly used as submission holds in Brazilian jiu-jitsu. In judo, chokeholds, known as shime-waza, are often subject to restrictions based on age or rank. Chokeholds are not allowed in sport sambo but are allowed in combat sambo. The chokeholds used in catch wrestling and shoot wrestling are the inspiration for the "chokeholds" in modern professional wrestling performances. Due to the effectiveness of chokeholds and their popularity in a wide variety of martial arts, they are most often used to force submissions in mixed martial art and submission grappling competitions. Some martial arts include instruction on , resuscitation techniques to heal a fighter choked to unconsciousness. Use in law enforcement (lateral vascular neck restraint) In law enforcement the goal is to force an uncooperative subject to submit without causing death or permanent injury. In this situation 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. Possibly the most important element of training for the use of chokeholds in law enforcement