(Note: I’m not talking about FFI, but healthy people.)

It’s said that we need sleep because waste products, such as adenosine (which is a CNS depressant) build up in our brains while we’re awake. When we sleep, the glymphatic system activates and flushes it out. Too much adenosine is known to cause a slower heart rate, the body temperature to decrease, immune system to weaken, hallucinations, and more.

I read about how a Chinese guy (in 2014 or 2012?) deliberately stayed awake for 11 nights with no sleep at all to watch the world cup, and he died. The articles said he died of sleep deprivation.

Here’s the part which confuses me. I understand why too much of a CNS depressant waste product in your brain would be deadly, since it’d supress vital functions such as breathing, heart rate etc. I’m just wondering why it wouldn’t make you automatically pass out and sleep, long before it got to that level as it’s something which very gradually builds up in your brain the longer you’re awake.