Featured Research

from universities, journals, and other organizations

New Study Shows People Sleep Even Less Than They Think

Date:
July 3, 2006
Source:
University of Chicago Medical Center
Summary:
A study of the sleep characteristics of 669 middle-aged adults found that people sleep much less than they should, and even less than they think. Published in the July issue in the American Journal of Epidemiology, the study also found that blacks sleep less than whites, men sleep less than women, and the poor sleep less than the wealthy.

A study of the sleep characteristics of 669 middle-aged adults found that people sleep much less than they should, and even less than they think. Published in the July issue in the American Journal of Epidemiology, the study also found that blacks sleep less than whites, men sleep less than women, and the poor sleep less than the wealthy.

Although participants spent an average of 7.5 hour a night in bed, they spent only 6.1 hours asleep. White women slept the most, 6.7 hours a night, followed by white men at 6.1 hours, black women at 5.9 hours and black men at 5.1 hours. Higher income also was associated with more sleep.

"People don't think they get enough sleep and they get less sleep than they think," said study author Diane Lauderdale, Ph.D., associate professor of health studies at the University of Chicago. "As we learn more and more about the importance of sleep for health, we find evidence that people seem to be sleeping less and less."

Studies suggest that average sleep times have declined since 1900, when people reported sleeping nine hours a night. Studies from the 1970s reported average sleep times closer to seven hours a night.

"Our study tells that we can't entirely trust those earlier surveys," Lauderdale said, "because people do not know how much they sleep."

This was one of the first large studies to combine sleep diaries with a technique called wrist actigraphy that uses a motion sensor -- worn like a watch -- to measure not just when people go to bed but when they fall asleep. Participants wore the device in the home for three days and nights. They also kept a log of their hours in bed.

Using the Actiwatch and nightly logs, Lauderdale and colleagues recorded how long people spent in bed (on average, 7.5 hours), how long it took them to fall asleep (22 minutes), how long they slept (6.1 hours), and their total sleep "efficiency" -- time asleep divided by time in bed (81 percent).

They found that sleep duration and sleep efficiency were "remarkably lower" than values reported in most previous studies, noted Stuart F. Quan of the University of Arizona in a commentary.

The researchers were particularly surprised by the short span and poor quality of sleep among African-American men -- 5.1 hours a night and 73 percent sleep efficiency.

"Although sleep scientists have generally accepted that the average sleep duration of Americans has been declining in parallel with our transformation to a frenetic 24-hour society," Quan wrote, "most sleep clinicians would consider those values indicative of sleep deprivation even by current standards."

Lack of sleep has long been connected with reduced ability to concentrate, trouble learning, decreased attention to detail and increased risk of motor vehicle accidents. More recent studies have tied chronic partial sleep deprivation to medical problems, including obesity, diabetes and hypertension.

This study may someday connect sleep loss to coronary artery disease. The 669 volunteers, aged 38 to 50, were recruited from the Chicago site (based at Northwestern University) of the CARDIA study, an ongoing project, begun in 1985, designed to assess long-term cardiovascular risk factors.

Although the study found significant variation based on race, sex and income it was not designed to get at the causes of those differences.

"People who make more money may have fewer worries," Lauderdale suggested, "or they may have more control over their sleep environment."

The findings, however, are "consistent with sleep being on the causal pathway between socioeconomic status (or race) and disease risk," the authors conclude.

"There are many temptations to sleep less," said Lauderdale, "but there is a growing body of evidence that this would be unwise."

"I try to get at least seven hours a night," she said. "I can't function the next day without it."

Additional authors of the paper include Kristen Knutson and Paul Rathouz from the University of Chicago, Lijing Yang and Kiang Liu from Northwestern University, Stephen Hulley from the University of California at San Francisco, and Steve Sidney Kaiser Permanente Northern California. The study was supported by grants from the National Institutes of Health.


Story Source:

The above story is based on materials provided by University of Chicago Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

University of Chicago Medical Center. "New Study Shows People Sleep Even Less Than They Think." ScienceDaily. ScienceDaily, 3 July 2006. <www.sciencedaily.com/releases/2006/07/060703162945.htm>.
University of Chicago Medical Center. (2006, July 3). New Study Shows People Sleep Even Less Than They Think. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2006/07/060703162945.htm
University of Chicago Medical Center. "New Study Shows People Sleep Even Less Than They Think." ScienceDaily. www.sciencedaily.com/releases/2006/07/060703162945.htm (accessed July 31, 2014).

Share This




More Mind & Brain News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dieting At A Young Age Might Lead To Harmful Health Habits

Dieting At A Young Age Might Lead To Harmful Health Habits

Newsy (July 30, 2014) Researchers say women who diet at a young age are at greater risk of developing harmful health habits, including eating disorders and alcohol abuse. Video provided by Newsy
Powered by NewsLook.com
It's Not Just Facebook: OKCupid Experiments With Users Too

It's Not Just Facebook: OKCupid Experiments With Users Too

Newsy (July 29, 2014) If you've been looking for love online, there's a chance somebody has been looking at how you're looking. Video provided by Newsy
Powered by NewsLook.com
How Your Face Can Leave A Good Or Bad First Impression

How Your Face Can Leave A Good Or Bad First Impression

Newsy (July 29, 2014) Researchers have found certain facial features can make us seem more attractive or trustworthy. Video provided by Newsy
Powered by NewsLook.com
Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins