Brain starts dying after oxygen deprivation of 4 mins. (?)

00:17:23 mark

<< The syndrome of narcotic overdose if done by IV heroin is very very rapid So within 30 seconds if you've taken an excessive dose you will stop breathing. You will subsequently lose your oxygen and increase your carbon dioxide and become comatose, and potentially start killing off brain cells within 4 to 5 minutes. You have a very short window at that point to be resuscitated, but if that's not reversed very very quickly, then you're going to succumb. With the heroin it really happens so quick it's almost always because you've stopped breathing. >>

It sounds like the doctor is saying one doesn't start having brain damage until 4 minutes after the flow of oxygen stops.

Is that really right? I'd think your brain starts dying much quicker (?)
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