How long a person can live without oxygen?

As a respiratory physiologist, I can tell you that the human body is highly dependent on oxygen to function properly. Without oxygen, cells begin to die, starting with brain cells, which are particularly sensitive to hypoxia, or low oxygen levels. The average person can only survive for a very short period without oxygen. The 3 minutes mark is often cited as a general guideline for how long a person can remain conscious without oxygen. However, this is a rough estimate, and survival times can vary significantly based on factors such as health, physical fitness, and the individual's acclimatization to lower oxygen levels. It's important to note that while some trained individuals, like yoga and meditation experts, might be able to hold their breath for longer periods, this does not mean they are not consuming oxygen. Their bodies are still using up the oxygen available in their lungs and bloodstream, and they would eventually need to breathe in fresh air to replenish their oxygen supply. After the initial period of unconsciousness due to lack of oxygen, if oxygen deprivation continues, permanent brain damage and death can occur. The irreversible damage to brain cells typically happens after about 5 minutes without oxygen, although this can happen more quickly in some cases.

Though it varies from person to person, on an average, 3 minutes is the maximum time where the person can stay alive without oxygen. Yoga and meditation experts may hold breath for longer than this, but these are very rare examples. In an absence of oxygen, brain cells begin to die and this effect is irreversible!