Question: How long would someone live without oxygen before they die?

Philip Dolan answered on 16 Jun 2011:

I think your brain starts to suffer permanent damage after 2 minutes of oxygen starvation. Some free divers can hold their breath for up to 5 minutes (I think), but that’s not starving their brains of oxygen, as they take an epically large deep breath before starting the clock (the same goes for whales/dolphins/seals etc.). There are some cases where (normally by falling into a freezing cold lake) peoples bodies immediately shut down, they lose consciousness and blood is pumped only to the heart and brain. In this way they can survive for ten or fifteen minutes without permanent damage.