By Rick Weiss
Washington Post Staff Writer
Wednesday, March 12, 2008
Americans are not as sleep-deprived as they think they are and, in fact, appear to be getting more Z's these days than they got a few years ago, according to an independent analysis of government statistics.
The new findings run counter to the widespread public perception that Americans are getting less and less sleep because of increasing workplace demands and the plethora of distractions available around the clock on the Internet and cable television.
"Many Americans work too much, but most do not seem to be cutting corners on their sleep to do so," said John P. Robinson, a sociologist at the University of Maryland, who led the analysis with faculty colleague Steven Martin.
Their report, "Not So Deprived: Sleep in America, 1965-2005," scheduled for release by the university today, finds that Americans on average got 59 hours of sleep per week in 2005, the latest year for which precise statistics are available. That is three hours more than in 2000.
The new numbers contrast significantly with the 2008 "Sleep in America" poll, the oft-quoted survey conducted annually by the Washington-based National Sleep Foundation, which advocates for better diagnosis and treatment of sleep problems.
Released last week, that survey concluded that Americans get an average of 48 hours of sleep per week.
The difference, experts said, reflects the two groups' methodologies. The Sleep Foundation survey asks Americans to estimate how much sleep they typically get. By contrast, the Maryland analysis draws upon detailed "time-use" data collected by the U.S. Census Bureau for the Department of Labor Statistics. In that approach, individuals must account for every minute of the previous day.
"This gives us a much better picture of where the time goes than when people just make an estimate," Robinson said.
The primary factor affecting the amount of sleep a person gets is whether he or she is employed, the new analysis shows. Apparent differences among men and women and people of varying ages and races effectively disappear when individuals' employment status is taken into account.
"Older people sleep more, but that's because they tend to be unemployed," Robinson said. "If you control for those differences, the differences in sleep disappear, too."
Most surprising are the hints in census data that sleep time may be increasing after many decades of virtually no change.
The new data show Americans getting an average of 8.5 hours per night in 2005, compared with eight hours in 2000. Most of the extra minutes of weekly sleep are coming on Saturday nights: 9.5 hours of which were spent slumbering in 2005, compared with 8.8 hours in 2000.
Friday night slumber grew to 8.9 hours from 8.5, and workweek sleep grew to 8.2 hours from 7.8.
Sociologists at the University of Toronto recently published a report of similar trends in Canada.
Addressing the contrast with the National Sleep Foundation data, Robinson said he is not surprised that people who are asked to simply estimate how much sleep they get tend to underestimate.
"It's a status symbol," he said. "If you are a good American, you work all hours. It's virtuous in American society to not get enough sleep."
The Sleep Foundation gets funding from the makers of sleep-related drugs and medical devices but says its surveys are conducted independently.
Christopher Drake, a psychologist at Henry Ford Hospital's sleep center in Detroit and a board member of the Sleep Foundation, agreed that sleep estimates are not ideal. However, he added, "Time-use surveys have issues, too. Tossing and turning from insomnia and the time spent 'waking up' or 'falling asleep' is often counted as 'sleep time' in those surveys."
That can lead to overestimates of time spent sleeping, Drake said, adding that part of the difference may also be because the foundation's survey focused on working Americans.
Robinson and Drake agreed that averages do not tell the whole story, and that some parts of society may be getting less sleep these days even as others -- the undereducated and unemployed among them -- may be getting more.
"The message we're trying to get across is not that everyone is sleep-deprived, but there are certain segments of the population living with a regular sleep debt, people getting less than six hours per night," Drake said.
That includes the one-third of night shift workers who report getting less than six hours of sleep per 24 hours, and the 43 percent of people holding down two jobs who say they get a good night's sleep, on average, only twice a month.
That is important, Drake said, and not only because sleepiness can lead to automobile accidents and other life-threatening errors. "Sleepiness is impairing their work, their relationships with their families and pretty much every aspect of their lives," he said.
One solution: naps. Less than half of the U.S. population takes two or more naps a month, according to the foundation, and 10 percent have taken a nap during a break at work.
"The bottom line for us is to tell people to make sleep one of their number one priorities," Drake said. "Because if you don't do that, then it easily falls to the bottom of the list."