the.com/sleepiness
Your brain quietly billing you for every hour of sleep it didn't get.
means The heavy, foggy pull toward sleep that comes from being tired.
from From 'sleepy,' built on 'sleep,' which traces back to Old English 'slæp' — part of an old Germanic word family (related to German 'Schlaf') whose deeper roots are lost to time. The '-y' makes it an adjective quality, and '-ness' turns that quality into a noun — the state of being overcome by it.
- caused by
- adenosine buildup, not willpower failure
- peak slump
- 2-4pm, biologically wired, not just lunch
- fix that fails
- caffeine just blocks the tired signal, doesn't erase it
- sleep debt
- accumulates and compounds, like interest you can't skip