How to Respond When They Go to Sleep

When someone goes to sleep on the mats, it’s almost always via a compression of the carotid arteries. The sudden loss of oxygenated blood rapidly lowers the brain’s metabolic state and causes unconsciousness within seconds.

Once that pressure is released however, blood flow resumes almost immediately, and normal function returns, and this is why the common response of elevating the legs, while well intentioned, can do more harm than good.

The practice itself comes from treating syncope (fainting); typically caused by systemic hypotension when blood pressure drops suddenly. In that situation, raising the legs helps push blood back toward the brain.

Mechanical compression, however, is not systemic hypotension. It is a localized, temporary interruption of blood flow that reverses when pressure is released. In this situation, leg elevation fixes nothing and distracts from what matters.

The best protocol here is the recovery position, and here’s why:

First, when someone is unconscious, the muscles that keep the airway open lose tone. If they are supine, gravity pulls the tongue and soft palate backward against the throat, which can block airflow partially or fully. This explains why an unresponsive person may struggle to breathe even with healthy heart and lungs.

Second is the risk of aspiration. This is when reflexes like gagging and coughing are suppressed during unconsciousness. If the person regurgitates, it can mean fluid enters the airway instead of leaving the mouth, and aspirated stomach contents can cause serious lung complications.

On their side, the tongue shifts forward rather than backward, and any fluid flows out of the mouth instead of into the windpipe. And, if convulsive jerking occurs, which is common after a choke, they are less likely to hurt themselves or block their airway.