Waking up between 2-4 AM and being unable to fall back asleep isn't about your bladder or room temperature...
It's a classic sign of mid-sleep neurotransmitter depletion.
Your brain burns through its remaining GABA reserves maintaining sleep. Once depleted, usually around 3 AM, your brain literally cannot maintain the sleep state. Cortisol spikes, adrenaline surges, and you're suddenly wide awake with your heart pounding.
This creates a vicious cycle:
Poor sleep → More stress
More stress → Faster depletion
Faster depletion → Worse sleep
Worse sleep → Complete breakdown