ROCHESTER, N.Y. — Night terrors. Sleepwalking. Daytime drowsiness. Insomnia. Bed-wetting.
Helping patients deal with these problems is the province of Dr. Donald W. Greenblatt, who practices in a relatively new specialty: sleep disorders.
Greenblatt, clinical assistant professor of medicine at the University of Rochester, directs the Sleep Disorders Center at St. Mary's Hospital in Rochester, where he studies the sleeping behavior of about 400 patients a year. It is one of about 100 such centers in the country, virtually all of which have sprung up since the late 1970s.
Sleep is part of a daily tapestry of biological rhythms of hormone levels, body temperature and alertness or sleepiness that has been called the body's clock, Greenblatt says.
"Natural cues like the rising of the sun or regular habits like getting up and going to bed at about the same time each day help 'set' these clocks," he says. "But when we jet across time zones or change work shifts, we upset the rhythms and then can't sleep when it's time to go to bed.
"It's easier for people to delay the cycle than to shorten it," he adds. "Studies have shown that when people are put in environments where there aren't any time cues at all and they're allowed to get up and sleep when they choose, they will develop daily cycles that last 25 to 27 hours."
Consequently, he explains, it's easier to readjust to local time if you're flying from east to west than the reverse. It's also easier to adjust to the return of standard time in the fall which, by turning the clock back, lengthens the day than it is to switch to daylight-saving time in the spring.
Shift workers--especially those who work rotating shifts--often have trouble getting the right amount of sleep because they frequently have to change their hours just about the time that their bodies are getting accustomed to the last shift.
Greenblatt's rule of thumb is that it takes about a day to adjust to every hour of change you make. If your work schedule begins eight hours later, it will take you about a week to get used to it.
For night owls who can't get up in the morning and people whose circumstances have changed, such as the late shift worker who goes back to school and must get up for 9 a.m. classes, there's a treatment called "chronotherapy" that resets the body clock.
"It's pretty simple," says Greenblatt, "but it takes several weeks. Say that you need to be in bed by 11 p.m. in order to be refreshed by 7 the next morning. But you've been going to bed at 4 a.m. If you tried going to bed at 11 p.m., which is much earlier than your usual bedtime, you probably wouldn't fall asleep.
"So chronotherapy puts people to bed later than usual. If a patient used to retire at 4 a.m., we ask him or her to wait until 6 a.m. before going to bed. In a day or two, we change the hour the patient retires to 8 a.m., and so on, until we move the patient around the clock and reach the correct new bedtime."
Though Greenblatt sees a fair number of patients who can't fall asleep when they want to, he says the majority of patients who consult him complain of being too sleepy during the day, or of falling asleep at inappropriate times.
One of the first things Greenblatt determines from a too-sleepy patient is whether he (it usually is a he) snores. Snoring is a symptom of obstructive sleep apnea--the closing off of airways to the lungs.
Snorers with apnea have smaller airways than other people, he says. During sleep, the airway may actually relax to the point of closing off the pathway for oxygen to reach the lungs. The brain senses that oxygen levels have dropped dangerously, so it "wakes up" the patient to get the breathing started again. The arousal may last less than a minute and the sleeper probably won't remember the episode, which might be repeated as many as 500 times during the night.
"Sleep disorders are more treatable than some other medical problems," says Greenblatt, who was trained as a specialist in lung diseases. "Patients get better, often lots better."
He offers these suggestions for a good night's sleep:
- Sleep only until refreshed. Sleep requirements vary from one person to the next; most people need seven to nine hours to feel their best.
- Sleep in a cool, quiet room. Temperatures above 75 degrees make you restless at night, and noise disrupts sleep even if you're not awakened by it.
- Exercise regularly, especially in the late afternoon. Studies show that people who do this increase their "delta" sleep--the kind that is most refreshing. Vigorous exercise shortly before bedtime will probably keep you awake, though, and exercise in the morning doesn't seem to affect sleep one way or the other.
- Don't drink alcohol before bedtime or take sleeping pills. Though they may cause you to fall asleep sooner in the short run, they can cause "rebound" insomnia when their effect wears off.
- Keep a regular schedule, getting up and retiring about the same time every day.