Early to bed and early to rise, something we learned as children, makes sense given the number of Americans who suffer from chronic sleep loss and sleep disorders.

About 10 percent of adults report not getting enough rest or sleep every day in the past month, according to a new four-state study released by the Centers for Disease Control and Prevention’s (CDC) Morbidity and Mortality Weekly Report.

The data from the four states–Delaware, Hawaii, New York, and Rhode Island–may not reflect national trends. But an additional study conducted by CDC utilizing data from the National Health Interview Study indicated that across all age groups the percentage of adults who, on average, report sleeping six hours or less has increased from 1985 to 2006.

Nationwide, an estimated 50 to 70 million people suffer from chronic sleep loss and sleep disorders. Sleep loss is associated with health problems, including obesity, depression, and certain risk behaviors, including cigarette smoking, physical inactivity, and heavy drinking.

"It’s important to better understand how sleep impacts people’s overall health and the need to take steps to improve the sufficiency of their sleep," said Lela R. McKnight-Eily, Ph.D., the study’s lead author and a behavioral scientist in CDC’s Division of Adult and Community Health. "There are very few studies to assess and address sleep insufficiencies; therefore, more needs to done to better understand the problem and to develop effective sleep interventions."

The study, "Perceived Insufficient Rest or Sleep--Four States, 2006," analyzed data from CDC’s Behavioral Risk Factor Surveillance System (BRFSS) survey. Among the four states, the percentage of adults who reported not getting enough rest or sleep every day in the past 30 days ranged from 14 percent in Delaware to 8 percent in Hawaii.

People concerned about chronic sleep loss should consult a physician for an assessment and possible treatment, such as behavioral or medical interventions, McKnight-Eily said. They can also try setting a regular sleep schedule and avoiding caffeine or other stimulants before bed, she said.

Variation for insufficient rest and sleep may be due to occupational or lifestyle factors. The causes of sleep loss could include busy schedules or shift work; irregular sleep schedules; or lifestyle factors such as heavy family demands, late–night television watching and Internet use, or the use of caffeine and alcohol, according to a 2006 Institute of Medicine report. The National Sleep Foundation reports that most adults need 7-9 hours of sleep each night to feel fully rested while school children aged 5-12 years require 9-11 hours, and adolescents aged 11-17 years require 8.5–9.5 hours each night.

The study also found that the prevalence of insufficient sleep decreased with age. An estimated 13.3 percent of adults aged 18-34 reported insufficient rest or sleep everyday in the past month compared to only 7.3 percent of adults ages 55 and older. While some studies have found sleepdisturbance more prevalent among older adults, results from this study are consistent with other research that supports the idea that older adults (who are more likely to be retired) make fewer complaints regarding impaired sleep and adapt their perception of what encompasses sufficient sleep.

In addition, the study showed that only one out of three (29.6 percent) adults said they did get enough rest or sleep every day in the past month.

The MMWR report said the definitions of "enough" (sufficient) sleep and "rest," and responses to the survey question were subjective and were not measured or equated to reports of hours of sleep per night. The report said the analysis cannot be compared directly with studies measuring hours of sleep. The survey question also did not define or distinguish between "rest" and "sleep."

The study was released in connection with National Sleep Awareness Week®, an annual campaign held in conjunction with Daylight Saving Time. For more information on the National Sleep Foundation, visit www.sleepfoundation.org.

For more information on CDC‘s Sleep and Sleep Disorders Program, visit www.cdc.gov/sleep.