Your brain depends on oxygen. Even just a minute or so of oxygen deprivation can cause a cascade of reactions that damage your brain. Cerebral anoxia occurs when your brain is completely deprived of oxygen. When oxygen flow is reduced—usually due to reduced blood flow—but not completely eliminated, cerebral hypoxia is the result.

In some cases, your brain responds to the loss by temporarily increasing blood flow in an attempt to provide more oxygen. Though this can save your life if your brain is deprived of oxygen, it can also cause cardiovascular episodes such as brain bleeding, strokes, and ruptured blood vessels in the brain, particularly if you have other cardiovascular problems.

Cerebral hypoxia can cause both immediate and long-term brain damage, and the course of recovery from a serious episode of cerebral hypoxia is unpredictable. Only a doctor can properly assess you, so if you suspect your brain has been deprived of oxygen, seek immediate medical care.

Types of Cerebral Hypoxia

Doctors classify hypoxia of the brain into four distinct categories, ranging from least to most severe:

  • Diffuse cerebral hypoxia causes mild to moderate impairment in brain function due to low blood oxygen levels. This sort of hypoxia is common among people who hold their breaths for too long, or who participate in sports that involve choking one's opponent, such as jiu-jitsu.
  • Focal cerebral ischemia occurs when there is oxygen deprivation in a specific area of the brain. This is usually the result of a hemorrhage, stroke, or blockage in a single blood vessel.
  • Global cerebral ischemia is a complete cessation of blood flow to the brain, and quickly leads to cerebral anoxia. Severe strokes, traumatic injuries such as gunshot wounds, choking, and suffocation can cause global cerebral ischemia.
  • Cerebral infarction is cessation of blood flow to multiple areas of the brain, and often causes extensive brain damage. A stroke is the most common cause.

Symptoms of Cerebral Hypoxia

Cerebral hypoxia is a medical emergency, and victims often know the cause, particularly if they've fallen or suffered another traumatic injury. When cerebral hypoxia is due to a stroke or other internal issue, symptoms can appear more slowly.

Some warning signs that your brain has been deprived of oxygen include:

  • Feeling light-headed.
  • Intense pressure in the brain or reddening of the face; this suggests the body is increasing blood flow to compensate for hypoxia. Some people experience very painful headaches.
  • Loss of consciousness. 
  • Seizures. 
  • Changes in mood, personality, or judgment. People suffering from hypoxia may make poor decisions, suddenly forget words, or not know where they are. 
  • Weakness, particularly on one side of the body. It's common for people having a stroke to be unable to raise both arms above the head, to have a crooked smile, or to experience paralysis on one side of the face. 
  • Sudden bleeding anywhere around the face, particularly if blood vessels in the eyes are ruptured. 

Short and Long-term Effects of Cerebral Hypoxia

The effects of cerebral hypoxia depend primarily on how long the brain is deprived of oxygen. Short-term diffuse hypoxia often produces no effects at all. For instance, a wrestler who loses consciousness with his opponent's arm around his neck will likely regain full functioning after he regains consciousness. People who experience this sort of short-term oxygen deprivation, though, will still experience symptoms. Those include:

  • Loss of sensation in one or more areas of the body.
  • Confusion, memory difficulties, or impairments of judgment.
  • Loss of consciousness.
  • Blurred vision or difficulty focusing the eyes on a single point.
  • Feeling nauseated or woozy.
  • A headache during or after the period of hypoxia.

When hypoxia lasts less than 60 seconds, it is unlikely to cause lasting damage. At two minutes, the risk of brain damage becomes more likely, while at three to four minutes, it becomes a near-inevitability. The long-term effects of cerebral hypoxia can include:

  • Damage to specific areas of the brain. The specific prognosis depends on which areas are damaged. For instance, severe damage to regions of the brain that govern speech and language may lead to aphasia.
  • Long-term loss of consciousness in the form of a coma. Some patients also enter a persistent vegetative state. This loss of consciousness may give the brain time to heal, but can also be a permanent state.
  • Epilepsy or persistent seizures.
  • Damage to motor skills, especially fine motor skills. Sometimes this damage is localized to just one region or one side of the body.
  • Death, either immediately after the deprivation or due to the side effects of hypoxia, such as stroke or other cardiovascular episodes.
  • Birth defects; hypoxia is a relatively common birth injury, and newborns who suffer prolonged oxygen deprivation may suffer chronic diseases such as cerebral palsy.

Treatment for Cerebral Hypoxia

The most important treatment for cerebral hypoxia involves removing the source of the oxygen deprivation. Choking victims may need the Heimlich maneuver or to be intubated. Blood clots might need to be removed, or the patient might need the assistance of a ventilator until the source of the oxygen deprivation can be discovered.

Thereafter, there is no specific treatment for cerebral hypoxia. The brain remains a mysterious organ, and we do not yet know how to reverse brain damage or regenerate brain cells—though experimental research has shown some promising results. Instead, doctors focus on addressing the symptoms of cerebral hypoxia. This typically means extensive physical, occupational, or speech therapy to teach your brain how to work around any damaged areas. Such therapy can be challenging and emotionally draining, but the more committed you are to challenging your brain, the more likely it is that you will see improvements in functioning. Some other treatments include:

  • Drugs to prevent future hypoxia episodes; this may include the use of blood thinners.
  • Antibiotics to treat infections that caused or resulted from the hypoxia.
  • Surgery to remove any blockages or to discover the source of the blockage.
  • The use of assistive gear, such as a wheelchair, to help you work around hypoxia-related motor skill deficits.
  • Psychotherapy to help you and your family find effective ways to cope with the long and short-term effects of your injuries.

Researching information on your own can provide useful context when talking to your physician and other medical professionals but it is not a substitute for medical care. Be sure to speak to your doctor about any questions you have regarding an injury or treatment.

Download our free guide with all of the important questions to ask your doctor by clicking the button below.

Important Questions To Ask Your Brain And Spinal Cord Injury Doctor.