W. Niel Teeples tells a joke about a Russian who'd never been out of his country. "I like Russia best," he says.

Teeples tells it because he relates to it. He didn't know he was sick and tired until he stopped feeling that way — until, after he had a heart attack, his wife, Donna, and a nurse were talking about the funny way he slept, sucking in breath and holding it, then gasping for air. The nurse said he had sleep apnea. An overnight stay at LDS Hospital's sleep disorders center later confirmed it.

Kim Murdock knew he felt fatigued. Sometimes he'd wake up more exhausted than he'd been when he went to bed. He could function all right as a respiratory therapist at Salt Lake Regional Medical Center, but if he sat at the computer or just paused for a minute, he'd nod off.

Hank Finch had days at work for the U.S. Forest Service when it was "almost impossible" to do even normal tasks. He'd force himself, then come home, sleep 10 hours or more, wake up tired and slog through another day.

Unlike many who are tired, their problem wasn't lack of sleep. It was the poor quality of their sleep. All three have been diagnosed with sleep apnea.

Other sleep disorders also take a devastating toll on men, women and children.

Americans, in large numbers, are tired. It shows up in lost productivity, depression, higher health-care costs, more car crashes and tattered relationships. Sleep deprivation may kill concentration or cause behavior problems, mood swings and memory lapses.

"We have a huge national sleep debt," says Dr. Christopher Jones, director of the sleep center at the University of Utah. "We are servicing that debt with high interest."

Sleep matters. Consider:

• One-third of adults — 50 million Americans — will experience a "chronic" period of sleep disturbance. For many, it's persistent.

• Drowsy driving is the No. 1 cause of automobile-related deaths in Utah, according to the Utah Department of Transportation.

• Fatigue increases the likelihood of a workplace accident.

• Sleep deprivation can cause weight gain. It boosts hormones that stimulate fat cells to grow, increasing appetite. It also stresses hormones that raise blood sugar.

• An hour of quality work when you're rested is worth about 2 1/2 hours of "muddling through with a foggy head," Jones says.

• Individuals have different sleep needs, but most people need between 7 and 9 hours sleep each night to function at their best. Most Americans get fewer than 7.

• Shift workers are prone to sleep deprivation. And 10 to 20 percent doze on the job, says the National Sleep Foundation.