It is impossible to biologically adapt to chronic sleep deprivation; the impression of 'getting used to it' is merely a loss of the ability to assess one's own level of fatigue.

noli's read

Shelby Harris's assertion is widely supported by chronobiology research. A pivotal study published in the journal 'Sleep' (Van Dongen et al., RCT) demonstrated that sleep-deprived subjects accumulate increasing cognitive deficits, even though they subjectively report not feeling 'more tired' after a few days. This phenomenon is explained by a decrease in objective alertness that is no longer correlated with the conscious perception of sleepiness. Meta-analyses consistently confirm that chronic deprivation impairs executive function, memory, and emotional regulation. The idea of biological adaptation to short sleep is therefore a documented cognitive illusion. The statement is precise, scientifically sound, and avoids exaggeration by focusing on the disconnect between perceived and actual performance.

the sources

1. 1Depner CM, Melanson EL, Eckel RH, et al. 2019