How quickly can brain damage occur after the heart stops beating and breathing ceases?

Brain damage can begin to occur as soon as four minutes after the heart stops beating and breathing ceases. This timeframe is critical because the brain relies on a constant supply of oxygen and glucose delivered by the blood. When the heart stops, blood circulation halts, leading to a lack of oxygen (hypoxia) and nutrients necessary for brain function.

Within the first few minutes, the vulnerability of brain cells increases significantly due to their high metabolic demand. After about four to six minutes of oxygen deprivation, irreversible damage may start to set in, which can result in severe neurological deficits or death. This is why the emergency response to cardiac arrest emphasizes immediate CPR and defibrillation to restore circulation and oxygenation to the brain.

Understanding this timeframe is crucial for healthcare providers, caregivers, and individuals trained in emergency response, as every second counts in preventing brain injury during cardiac emergencies.