How long a person can survive without oxygen?

As a medical professional with expertise in respiratory health, I can provide you with an informed answer to your question. Without oxygen, a person's survival time can vary significantly depending on factors such as health, physical activity, and environmental conditions. In general, a healthy person at rest can survive for about 3 to 5 minutes without oxygen. This is because the brain and other vital organs require a constant supply of oxygen to function properly. If deprived of oxygen, brain cells begin to die after just a few minutes, which can lead to severe and irreversible damage. However, there are cases where individuals have survived longer periods without oxygen, such as during medical emergencies or accidents where resuscitation was successful. In some instances, trained divers can hold their breath for several minutes, but this is not a typical scenario and comes with significant risks. It's important to note that the survival time without oxygen is not a fixed number and can be influenced by various factors, including the individual's overall health, the level of physical exertion, and the specific conditions of the environment.

The brain can survive for up to about six minutes after the heart stops. The reason to learn cardiopulmonary resuscitation (CPR) is that if CPR is started within six minutes of cardiac arrest, the brain may survive the lack of oxygen. After about six minutes without CPR, however, the brain begins to die.