text: The Epworth Scale is a short questionnaire that measures this phenomenon.
full_question: The Epworth Scale is a short questionnaire that measures this phenomenon. K-complexes and namesake "spindles" form during one type of this phenomenon, during which nearly half of all growth hormone production happens. "Z-drugs" like zolpidem and zopiclone treat defects in this phenomenon. Stages of this process, from 1 to 4, can be measured on an EEG. Some scientists believe that in humans before the Industrial Revolution, the (*) "polyphasic" form of this phenomenon dominated. Obesity is a common cause of interruptions in breathing during this phenomenon known as obstructive apneas. Acetylcholine dominates during the REM phase of this process. For 10 points, name this physiological process that is impaired in people with insomnia.
first_sentence: The Epworth Scale is a short questionnaire that measures this phenomenon.
raw_answer: sleep [or REM sleep; or rapid eye movement sleep; or NREM sleep; or non-rapid eye movement sleep; or polyphasic sleep; accept other forms]