How Long Can Your Brain Survive Without Oxygen?

The human body needs oxygen to sustain itself. The decrease of oxygen to at least one body part is known as hypoxia. The total lack of oxygen is known as anoxia. Brain cells are destroyed after 4 to 6 minutes without oxygen. When the flow of oxygen to the brain is completely cut off, a person will lose consciousness within 10 seconds. Extended hypoxia leads to brain damage and ultimately death.

The brain is the body’s largest user of oxygen, even though it makes up less than 5 percent of the body’s weight. The brain consumes 20 percent of the body’s needed oxygen. Cerebral hypoxia is the deficiency of needed oxygen to the brain. According to the National Institute of Neurological Disorders and Stroke, there are several causes of cerebral hypoxia, and most are related to accidents or health complications. These include smoke inhalation, head trauma, choking, carbon monoxide poisoning, drowning, drug overdose, stroke and strangulation.

Symptoms in cases of mild cerebral hypoxia are inattentiveness, poor decision making and uncoordination. In severe instances of hypoxia, a person will be unresponsive and fall into a coma, stop breathing and not respond to light. Once there is only blood pressure and a heart beat, the person may be brain dead.

The lack of oxygen to the brain can result in a person entering a vegetative state where the person’s bodily functions such as breathing still exist, but the person is unresponsive. The majority of patients who reach this state often die within a year, according to Shands HealthCare, which is affiliated with the University of Florida Health Science Center. How long a person survives after suffering oxygen deprivation varies according to how much treatment is given to prevent other medical difficulties. Complications also can include bed sores, pneumonia and the development of vein clots.

Since hypoxia often occurs unexpectedly, the condition is difficult to avert. Prevention often relies on what causes the condition. However, performing CPR immediately on a person who suffers from hypoxia can be a life-saving treatment. If someone suffers from hypoxia, get medical treatment immediately by calling 911.

The outlook for someone who has suffered from oxygen deprivation depends on how long the person went without oxygen and whether brain damage occurred, states the National Institute of Neurological Disorders and Stroke. People can usually make a full recovery if they were unconscious momentarily. The more time a person spends in an unconscious state, the less the chance for a full recovery. While recovering, a person can suffer from psychological and neurological damage, including amnesia, hallucinations and muscle spasms.