Have you ever wondered why you feel tired all the time, or why your dad snores so loudly?

These are the kinds of questions that Dr. Clete Kushida, a researcher at the Stanford Sleep Clinic, and Dr. William C. Dement, a professor in the Department of Psychiatry and Behavioral Sciences, answered at a colloquium sponsored by Stanford Continuing Studies on Saturday.

Sleepless at Stanford

Dr. Kushida, who has been researching sleep and associated disorders for over 20 years, kicked off the event by discussing current research and potential treatments for many sleep disorders. He lectured on such ailments as sleep apnea, insomnia, narcolepsy, sleepwalking and Restless Leg Syndrome.

Kushida defined insomnia, which affects nearly 50 percent of American adults, as being more than just a problem of not being able to sleep at night. The pervasive disorder includes difficulty initiating and maintaining a restorative sleep and is caused by time zone changes, late-night work shifts and irregular sleep and waking times.

Insomnia is more than just a nuisance. It can result in poor job performance and potentially dangerous fatigue, according to Kushida.

Kushida’s research suggests that the disorder can be linked to the fact that the bedroom environment becomes associated with an awakened state.

Researchers believe that there are both psychological and biological causes for insomnia, but the evidence remains inconclusive.

“If you look at this, it’s called ‘psycho physiological’ and that basically tells you that we don’t have a clue what’s going on,” Kushida joked.

Kushida gave some advice that many college students would find surprising and even distasteful. He warned against taking naps in the middle of the day because they tend to disrupt regular sleeping patterns

He also cautioned against excessive use of stimulants such as nicotine and alcohol, which can also make it difficult to sleep.

The Dangers of Sleepwalking

Kushida also spoke about another common nocturnal ailment — sleepwalking. Although the thought of bumbling sleepwalkers elicits laughs, the effect on the victim can be surprisingly severe. Sleepwalkers have a 60 percent chance of injuring themselves if they are not woken up or otherwise stopped during the incident, according to Kushida.

“We get patients coming in with lots of cuts and bruises,” Kushida said. “They’ll jump out of bed and go straight for the window . . . we also tell them that if they’re traveling, to avoid getting rooms above the first floor.”

But in addition to causing harm to the patient, sleepwalking can result in surprisingly morbid conclusions and difficult legal situations for family and even innocent bystanders.

“We actually get quite a few calls asking for a number of us to be expert witnesses in medical and legal cases,” Kushida said. “There have been a number of cases when people have actually committed violent acts while sleep walking.”

Kushida cited a case in which a sleepwalking man stabbed his mother and brutally beat his father-in-law. The patient involved had a history of sleep problems and was eventually acquitted by a jury.

In another case that ended similarly, a man with a record of sleep disorders who assaulted another individual with a butcher knife and rolling pin.

Although the consequences of sleepwalking are rarely so dire, the condition remains a nuisance to many. Kushida explained that, other than taking certain medications and being careful, there are no agreed-upon treatments for sleepwalking.

Paying Back the Sleep Debt

Dement shifted the focus of the colloquium away from clinical sleep disorders toward a question that students routinely ponder in their 9 a.m. lecture classes: Why are we perpetually tired and what can we do about it?

Dement said that the only source of tiredness is sleep debt, which is a number that can be found by subtracting the amount of sleep gotten in one night from the eight-hour recommended daily average. This amount can be added up over the course of many days, creating cumulative sleep debt.

“Healthy young adults generally feel tired all the time or nearly all the time, and that’s sleep deprivation,” Dement said. “Whatever they call it, being unmotivated or being tired, that is all sleep debt.

“Ninety-five percent of Stanford students believe you can get too much sleep, and it’s counter-productive,” he added.

In order to prove his hypothesis, Dement set up the “Stanford Summer Sleep Camp,” for which he and his research team took over a residence hall and restricted the inhabitants’ sleep to five hours a night. Each day the experiment continued, the students’ alertness level, measured by the amount of time it took to fall asleep in bed, progressively decreased, suggesting a direct relationship between sleep debt and alertness.

“The larger your sleep debt the more tired you will feel, the more impaired you are, the more likely you are to become drowsy,” Dement said. “Many students feel the best sleeping occurs in lecture.”

“Sleep debt does not just dissipate; it will continue to accumulate until it is alleviated by extra hours of sleep,” he said.

Dement said that though he could not say exactly how much sleep debt constitutes a harmful amount, "50 hours is bad, and half of all college students have 50 hours or more sleep debt.”

Dement also said that many tragedies, such as the 1989 Exxon-Valdez oil spill and the 1986 Challenger Space Shuttle explosion could be attributed to excess sleep debt.

After the sleep deprivation experiment, Dement attempted to see what would happen when students were subjected to the opposite — 16 consecutive nights of 12.5 hours of sleep. This experiment yielded exactly the results he was looking for: students with sleep satiation reported feeling great and exhibited above-average reaction times.

Considering this evidence, the question remains as to why students sometimes still feel tired even after getting 16 hours of sleep. Dement said that students might be waking up at a time of day in which they are already accustomed to feeling tired, what he terms a “sleep trough.” He said that dehydration could also be a cause of tiredness.

“The key is maintaining consistent, sufficient sleep,” he said.

Dement is currently working on a nationwide “late to school” movement, which promotes starting primary school later than the standard 8 a.m. The movement is based on studies that show going to school later could tremendously improve academic performance and prevent up to 175,000 absent days.