You can survive in a pure oxygen atmosphere for a short period, but it's not ideal for long-term survival. Breathing 100% oxygen at sea level can be tolerated for about 24-48 hours without serious tissue damage. However, longer exposures can lead to definite tissue injury.
The reason we can't survive in 100% oxygen indefinitely is due to oxygen toxicity. Our bodies have evolved to thrive in an atmosphere with a specific oxygen concentration (around 21%). When we breathe pure oxygen, the high concentration overwhelms our cells, leading to several detrimental effects:
- Oxygen radicals: These highly reactive molecules damage the fats, proteins, and DNA in our bodies, impacting lung function, vision, and other vital systems.
- Inflammation: Excessive oxygen exposure triggers inflammation in the lungs, potentially leading to respiratory distress.
- Oxidative stress: The increased oxygen levels can cause an imbalance in our cells, leading to oxidative stress, which can damage our cells and contribute to aging.
While breathing 100% oxygen at normal atmospheric pressure is dangerous, it's possible to survive for a longer duration at lower pressures. This is why astronauts breathe 100% oxygen in spacecrafts, where the pressure is reduced.
