The time it can take to die of hypoxia is pretty short.
When you're dying of hypoxia your brain is starving for oxygen and within 5 minutes of hypoxia and without oxygen your brain cells can begin to die off.
And within 10 to 15 minutes you can die of hypoxia so that's why hypoxia is a very serious thing and requires medical attention right away.
Hypoxia occurs when there is not enough oxygen getting to the brain which can cause death in just 10 to 15 minutes if not treated medically in time.
So if you think someone may be having trouble breathing and getting oxygen you need to seek medical attention for that person right away to give the person a good chance of surviving.