If you're feeling well rested this morning, it might be because you live out West.

Residents of western states experience fewer restless nights than people in other regions of the country, according to data found in a new study by the Centers for Disease Control and Prevention. Several Midwestern states, including North Dakota and Wisconsin, also reported a low percentage of residents who don't get enough sleep.

The study, which was based on a national telephone survey, found that 11.1 percent of those surveyed said they hadn't experienced a good night's sleep in at least a month. That rate was highest in West Virginia (19.3 percent) and lowest in North Dakota (7.4 percent.)

Half of the twenty best-rested states are in the western U.S., according to the study. In Wyoming, one in 10 residents reported they hadn't gotten a good night's sleep in at least 30 days.

Dr. Ammar Hussieno, who evaluates sleep studies at Wyoming Medical Center's Sleep Lab, said he was surprised the survey found such geographic differences.

"I'm not sure how to explain that," he said.

A state's demographics might play a role, he speculated. The study found women and younger adults were more likely to suffer sleepless nights than men and people over 65. Poor sleep was also more common among the unemployed and high-school dropouts.

The study was based on the caller's own perceptions of good sleep, rather than a specific number of hours. People generally underestimate how much sleep they get, Hussieno said.

"People have a tendency to say, 'Well I just slept four hours last night,' but in fact, they slept six hours or more," he said.

Most people need about eight hours of sleep, although the exact amount various somewhat depending on the individual.

The public, and even some physicians, tend to discount the importance of sleep, Hussieno said.

"A patient with depression, it's not the first thing you'd think of, that they are not sleeping well. But that might be the reason for the depression," he explained.

Lack of sleep has been linked to a variety of other health problems, including anxiety, stress and chronic pain. There's also evidence that sleeplessness is tied to obesity.

A number of factors can lead to sleep problems, Hussieno said. For the majority of people, sleeplessness is connected to situational issues like work or a stressful event. Others wake up in the night for pathological reasons like sleep apnea -- a disorder where a person temporarily stops breathing while asleep -- or restless leg syndrome.

Reach reporter Joshua Wolfson at (307) 266-0582 or at josh.wolfson@trib.com. Visit tribtown.trib.com/JoshuaWolfson/blog to read his blog.

Get some sleep

To get a good night's sleep, Dr. Ammar Hussieno recommends avoiding alcohol, stimulants like caffeine and bright lights in the late evening.He also advises against sleeping or eating in the room where you sleep.