John P. Robinson, a sociologist at the University of Maryland, and Steven P. Martin report that Americans do, in fact, get the recommended average of 8 hours of sleep per night. This in contrast to the findings of the National Sleep Foundation (NSF)’s most recent “Sleep in America Poll.”
The study, released today, investigated 24-hour sleep diaries collected from 1965 to 2005. Sleep diaries require respondents to report only on “yesterday” in chronological order from early morning until the morning “today”. The study’s report explains the contrast between its results and those of the NSF’s annual poll by calling the NSF’s questions “vague and ambiguous questions about vague and ambiguous time periods.”
Robinson and Martin found that time diaries taken from 1965-2001 reported American adults do get the recommended 7-9 hours of sleep per night, sleeping an average of 8 hours per night, 56 hours per week. The most recent diaries, from 2003-2005 included 37,000 respondents and showed the average hours of sleep per week actually increased to 59 hours.
These diaries reported on every day of the week, and all diaries from 1975 reported on every season of the year. The NSF’s most recent poll targeted a random sample of 1000 Americans from September 25 – November 19, 2007.
The results of the latest Sleep in America poll conclude that American’s only get 6 hours and 40 minutes of sleep per night on average.
A copy of the study, “Not So Deprived: Sleep in America, 1965-2005,” is available to media on request. An earlier version of the paper was presented at an academic meeting in October of 2007. The raw data are available at http://webuse.umd.edu.