New Day for Night Owls: Sleep Study Aims at Resetting Internal Clocks

Washington Post

As a child, he would sit cross-legged on his bed in the dark, wide-eyed, wide awake. He would stare out of his bedroom window for hours on end.

His night vision was acute. Even today, he says, he can walk through a dark house as though it were lit, “while my wife just stumbles along behind me.”

“I always knew I was a night person,” he said. At 34, he is a technical consultant and works out of his house, so he is able to set his own hours.

This is fortunate, because he is still a night person, still out of sync with the world, still suffering from what the specialists have named “delayed sleep phase syndrome.”


He’s an owl in a world of larks--terms devised by researchers studying the syndrome. And although this may have some advantages for some people some of the time, by and large this man would rather spend the night sleeping like everyone else.

Chronic Jet Lag

As a rule, he cannot fall asleep much before 3 or 4 a.m. And if he has to waken before 11 a.m., he walks around all day in a daze. In essence, he is in a state of chronic jet lag.

What is supper time for most of the world is just about the time he gets going.


An article a few years ago on sleep disorders made him aware that his problem was not unique and that there might be some help for it.

Sleep studies are a relatively new phenomenon, although the phase-delay syndrome was described as long ago as 1836: “They lie awake,” wrote a 19th-Century doctor, “for perhaps two or three hours after going to bed, and do not fall into slumber till toward morning.

“Persons of this description often lie long and are reputed lazy by early risers, although it is probable they actually sleep less than those early risers themselves.”

One treatment for the syndrome was developed in the 1970s and reported on by leading U.S. sleep specialists, including Dr. Charles Czeisler of the Harvard Medical School.


Czeisler, then at Stanford University, and others put their night-owl patients on a program that delayed their bedtime by an hour or two a night until they had moved their 4 a.m.-to-noon sleep periods forward to 6 a.m. to 2 p.m., to 9 a.m. to 5 p.m., continuing round the clock until they got to an appropriate 10 or 11 p.m. to 6 or 7 a.m.

Day and Night

Sometimes the treatment, called chronotherapy, required lengthy periods in a sleep laboratory where no external cues came from the environment--whether, for example, it was night or day.

At first the patients were allowed “free running,” allowed to sleep when they were sleepy, wake and eat when they felt like it.


Most people in such circumstances settle into about a 25-hour cycle, from which came the term circadian --from the Latin circa, which means “about,” or about a day.

Most people have an internal clock that adjusts to the 24-hour day. The owls apparently adjust, too, but their “nights” are everybody else’s days.

The chronotherapy seemed to work quite well for some owls, at least for a few months, but gradually their sleep rhythms slipped deeper into the night, and their owl natures reasserted themselves.

The 34-year-old man who always had been a night person said he tried chronotherapy on his own and worked his way round the clock in about six weeks. But he, too, found that although this helped for a few months, he eventually was again lying awake until 3 or 4 a.m.


The owl syndrome differs markedly from insomnia, because the owls do get their full complement of good sleep--six to eight hours a day. But by normal standards, they are the wrong six to eight hours.

The true insomniac may sleep long enough but still feels unrefreshed. When owls are forced to live like larks, they may suffer the same symptoms exhibited by insomniacs.

Treatments With Lights

Now the patient described here will be working with scientists in the psychobiology branch of the National Institute of Mental Health to see if his internal sleep-wake clock can be reset by the same light treatments used in seasonal affective disorder syndrome.


Dr. Norman Rosenthal, a staff psychiatrist at the institute, has shown that some manic-depressive patients whose moods vary with the length of the day--low in the winter and high in the summer--can benefit from winter exposure to artificial full-spectrum lights.

On the basis of some research done elsewhere, Rosenthal believes that owls, people with delayed sleep phase syndrome, may also benefit from the artificial lights, even though their moods are not necessarily involved in the syndrome.

Rosenthal credits a former institute colleague, Dr. Al Lewy, now at the Oregon Health Sciences Center in Portland, with demonstrating that in people as well as animals, “light exposure at different times of the day will do different things to circadian, or daily, rhythms.”

The researchers found that “if you expose the animal to light at certain times, it will bring the rhythms earlier; if you expose the animal to light at other times, it will bring the rhythms later. And at certain times, known as the ‘dead zone,’ light does nothing at all to the circadian rhythms.”


Now, Rosenthal said, Czeisler has published a study in the journal Science of an elderly woman whose exposure to bright lights caused a six-hour phase shift in a relatively short time.

As a result, Rosenthal said, “We are being encouraged to believe that if light is administered in the right way, perhaps humans can also have their rhythms influenced by light.”

Indeed, said Rosenthal, some researchers believe that the seasonal affective disorder may be a variety of delayed sleep phase syndrome--a belief not shared, however, by Rosenthal and his institute team.

Synchronizing Clocks


Most people adjust their 25-hour circadian rhythm to a 24-hour day virtually automatically, responding to environmental cues--such as a 9 a.m. class or a 6 a.m. daily jog, and whether the sun or moon is high in the sky.

If, for some unidentified reason, this automatic daily resetting is malfunctioning, it would be easy for an individual to run on his 25-hour day and become thoroughly out of step with the rest of the world, rhythmically speaking.

Indeed, until recently, the sleep specialists held that the human circadian clock was not at all sensitive to light. As Czeisler wrote in Science, “The unexpected magnitude, rapidity and stability of the shift challenge existing concepts regarding circadian phase-resetting capacity in man.”

Rosenthal and his colleagues, while continuing studies of seasonal depression, are setting up a study to see if “light applied just in the right way, judiciously administered, might be able to influence for the good the rhythms of the (delayed sleep phase syndrome) people.”


People interested in participating in the National Institute of Mental Health study may write to Owl Study (or seasonal depressives to the Seasonal Affective Disorder Study) 4S239, Building 10, National Institute of Mental Health, National Institutes of Health, Bethesda, Md. 20892; (301) 496-2141.