A Japanese research team has found that more than 40% of people who felt that they slept enough actually lacked sleep.
The team, led by Masashi Yanagisawa, professor and director of the University of Tsukuba’s International Institute for Integrative Sleep Medicine, said Tuesday that there were gaps in many cases between self-assessments of sleep length and quality, and the results of analyses such as those by brain wave examinations.
The team concluded that it was hard to make diagnoses of sleep condition based only on self-reported information and that objective measurement is important. The study results are to be published in an online edition of the U.S. journal Proceedings of the National Academy of Sciences.