Needing very few hours of sleep is extremely rare. Basically everyone who claims to get along with less than the usual 7-8h of sleep do worse in various cogniti

Needing very few hours of sleep is extremely rare. Basically everyone who claims to get along with less than the usual 7-8h of sleep do worse in various cognitive performance tests and most likely will suffer in longer term as well. Matthew Walker writes about this in his excellent book Why we sleep.