“…34,35,37,40,47,48 Namely, three of the existing studies used polysomnography, 37,47,48 which is considered as the gold standard of sleep measurements. 69 In this direction, others have used less complex and more practical methods of nap recording, such as actigraphy or accelerometers. 34,35,40 By contrast, the majority of the studies (71%) have provided napping opportunity without 29,30,33,42,49 or with 31,32,43,45,46 subjective measures of nap recording; thus, in these studies the exact amount of sleep was not adequately quantified.…”