ELLENSBURG — Most people recognize when they’re not getting enough sleep. They feel tired and may be irritable. They can’t concentrate or remember as well as usual. But missing sleep may be more unhealthy than you know. In severe cases, people not getting enough or the right type of sleep can die.

“You need to get enough sleep,” says Dr. Geoffrey Greenberg, who comes to Ellensburg each Wednesday to conduct the sleep clinic. He says there are several health problems associated with lack of sleep, including problems with the immune system and the heart.

Obstructive sleep apnea is a condition where the muscles that support the upper airway relax so much during sleep that the airway closes. The sleep is interrupted by an inability to breath for a short time. The interruptions can occur hundreds of times a night and put a strain on the heart.

“Reggie White died of sleep apnea,” says Greenberg. He says studies have shown that 40 percent of people who have untreated obstructive sleep apnea die within eight years.

White, the 43-year-old, all-pro, professional football player who died in 2004, was one of the more high-profile cases of sleep apnea, but it is a condition more common than diabetes, says Greenberg.

“About 4-5 percent of the population have sleep apnea,” says Greenberg. That translates into about 15-20 million Americans. While being overweight may contribute to the disorder, it isn’t confined to people who weigh too much.

“About 10 percent of the people with sleep apnea are normal weight,” says Greenberg.

Diagnosing and treating sleep disorders such as sleep apnea is what Greenberg does at the the Sleep Center at Memorial. He has been coming to Ellensburg weekly for the last 10 years or so to treat patients. Each Wednesday at Family Health Care at 107 E. Mountain View Ave.

In addition to sleep apnea, Greenberg says people come to the sleep center for a variety of other sleep problems.

He says some people come because they are tired during the day, one of the key symptoms of sleep apnea. Others come because they can’t get to sleep at night; some come because of abnormal sleep behavior, such as sleepwalking and others come because their circadian rhythm — their internal clock — is off. They can’t sleep when they want, although eventually they do sleep.

All are treatable conditions, some more easily than others.

Sleep apnea can be treated with pressure therapy, which is done with a device that provides continuous air pressure to the upper airway through the nose while the person sleeps, effectively keeping the airway from collapsing. It works for many people.

“Eighty percent of the people say they haven’t felt that well for years,” says Greenberg.

The pressure therapy, called continuous positive airway pressure, is covered by insurance. It involves a machine, which costs about $700.

Consultation is the first step towards treatment. If Greenberg believes the person may have sleep apnea, they are asked to wear a wristband, which measures their blood oxygen level. If the levels are not normal, a sleep test may be needed, which requires an overnight stay in Yakima at the sleep center.

Greenberg says he has about 30 people a week wearing wrist monitors. Of those, 30-40 percent indicate a problem, a high rate.

Many people come because of insomnia, the inability to initiate or maintain sleep.

“A lot of people come for that,” he says. The most common reason for insomnia is poor sleep habits. While medication can be helpful, Greenberg says it isn’t a cure all.

“People think they can just take a pill but it takes more than that,” he says. Sleeping pills can put you to sleep but don’t cure sleep apnea, for instance.

“Sometimes the best medicine is a sleeping pill left in the medicine cabinet,” Greenberg says. Even if they don’t take it, the security of knowing that they have a sleeping pill relieves anxiety and allows some people to go to sleep naturally.

Exposure to light is one way to treat sleep disorders. There is something about light that resets the body’s internal clock.

Greenberg says people should only use the bed for sleeping and sex, not to eat in or work in.

“It’s amazing what people do in bed,” says Greenberg. But working in bed gives the body the wrong message. Instead of associating bed with sleep, the bed becomes associated with work and the person becomes more alert.

“The job is to break that association,” says Greenberg.

Greenberg says you don’t have to be an adult to have sleep problems. And when children have pediatric sleep apnea, it can affect their ability to learn, in addition to other problems.

He says as many as half the youngsters diagnosed with attention deficit hyperactivity disorder are not getting enough sleep. When children don’t get enough sleep they become hyperactive, he says.

“A lot of ADHD is misdiagnosed,” says Greenberg. If the child has a sleep disorder, it is more serious than when an adult has one because the young person’s mind is still forming.

Youngsters need more sleep than adults and between video games, a hectic schedule and staying up too late; many simply do not get enough sleep.

“They’re sleep deprived,” says Greenberg. “They stay up too late.”

He says youngsters typically need nine or 10 hours of sleep daily, while adults need seven or eight hours.

Greenberg says education is an important part of his job.

“Sleep medicine is about education,” he says. “It’s about helping the patient understand their self.”