Cerebral hypoxia causes

Cerebral hypoxia can be caused by any event that severely interferes with the brain’s ability to receive or process oxygen. This event may be internal or external to the body.

Mild and moderate forms of cerebral hypoxia may be caused by various diseases that interfere with breathing and blood oxygenation. Severe asthma and various sorts of anemia can cause some degree of diffuse cerebral hypoxia. Other causes include work in nitrogen rich environments, ascent from a deep water dive, flying at high altitudes in an un-pressurized cabin, and intense exercise at high altitudes prior to acclimatization.Severe cerebral hypoxia and anoxia is usually caused by traumatic events. Examples include choking, drowning, strangulation, smoke inhalation, drug overdoses, crushing of the trachea, status asthmaticus, and shock.^[1]

It is also recreationally self-induced in the choking game and in autoerotic asphyxiation.