It’s believed we need sleep because of a waste product called adenosine builds up in our brains while we’re awake. When we’re unconscious the waste stops building up and the CSF in the brain gets rid of it. Adenosine is a CNS depressant and works on the same receptors as sleeping pills. Eventually your nervous system would be so depressed you’d just fall unconscious as if you took some sleeping pills.
Its not the lack of sleep that kills you, it is the stress on your body from not sleeping for long periods of time causing things like heart failure and aneurysms.
I have underlying health issues so I see the symptoms stronger and faster than most. I start trembling. My blood pressure destabilises and jump high to low. I get confused and mess up mundane tasks like starting the coffee maker without putting water in it
If you’ve ever let your blood sugar get too low, where you started seeing spots and shaking and getting dizzy, it’s a lot like that