How long can the human brain survive without oxygenated blood?

The human brain is highly dependent on a continuous supply of oxygenated blood to function properly. Without oxygen, brain cells begin to suffer damage relatively quickly. Generally, brain cells can survive for about 4 to 5 minutes without oxygen before irreversible damage begins to occur. This timeframe is critical because the longer the brain is deprived of oxygen, the greater the likelihood of serious and permanent neurological damage.

After about 4 to 5 minutes, the brain's cells might start dying off, leading to potentially severe outcomes such as loss of cognitive function, motor control, or other vital abilities. In some cases of specific medical interventions, there are rare instances of people surviving longer durations without permanent brain damage, but these cases are exceptional and not the norm. Therefore, the 4 to 5 minutes timeframe is widely accepted in the medical community as a standard threshold for irreversible brain injury due to oxygen deprivation.