Why sleep matters

Meir H. Kryger, M.D., was giving a morning lecture on sleep disorders when he spotted the physician who’d invited him to speak slouched in the front row, deep in slumber.

Kryger approached his host, woke him, and began to interview him. “I wanted my audience to learn how to ask questions about sleepiness,” recalled Kryger, a professor of medicine (pulmonology) at the medical school. When Kryger asked, “Do you ever fall asleep while driving?” his host replied, “Doesn’t everybody?”

“A lot of people don’t appreciate that they have a symptom that can be really significant—and dangerous,” said Kryger in an interview. (Sleepy drivers cause one in five car crashes.) To help readers recognize sleep disorders in themselves and in people around them, Kryger has written The Mystery of Sleep: Why a Good Night’s Rest Is Vital to a Better, Healthier Life. The book discusses sleep-related phenomena, including sleep apnea, nightmares, sudden infant death, and restless legs syndrome. The book explains how to minimize the harms of shift work, lists “the thirteen commandments for fighting insomnia,” and outlines a plan for minimizing jet lag. Kryger also considers “secondhand sleep problems,” addressing the travails of bedmates whose partners snore, grind their teeth, or fidget nonstop.

Like the doctor who snoozed during that lecture, Kryger said that many people don’t recognize that drowsiness could signal a serious sleep disorder or even a disease such as cancer. And sometimes the signs aren’t obvious: Falling asleep in a movie theater can suggest a sleep problem, but so can moodiness, memory lapses, or dreaming while half awake. Readers can rate the probability that they suffer from a disorder by using the book’s modified Epworth Sleepiness Scale. For those who go on to seek medical advice, Kryger warns against speaking in generalities: Rather than saying, “I’m tired,” patients should specify changes in mood and behavior.

Women report more sleep problems than men do. In a National Sleep Foundation poll, 60 percent of the thousand women questioned said they slept well only a few nights per week. Kryger says women are often misdiagnosed, however; doctors conclude that they are depressed when their symptoms actually suggest a sleep disorder.

Women constitute about a third of the roughly 7.4 million Americans believed to have obstructive sleep apnea, in which blocked airways cause snoring and pauses in breathing during sleep. The condition can lead to heart disease and other serious illnesses. Although sleep apnea affects not only women but babies and children and even snub-nosed dogs such as Boston terriers, the stereotypical sleep apnea sufferer is an overweight older man. As a result, Kryger said, women with apnea are often misdiagnosed as suffering from depression. He called that “a failing of the medical-education system. Doctors do not know enough about sleep.”

Undergraduates show a keen interest in the topic, however. When Kryger offered a class on sleep at Yale College last fall, more than 100 students vied for 18 spots. Similarly, undergraduates flock to Stanford’s “Sleep and Dreams” course, where Kryger recently guest-lectured; the class has been taught since 1970, and former students include psychologist and Yale President Peter Salovey.

The Mystery of Sleep notes that President Barack Obama rarely got the seven to nine hours of sleep recommended for adults. Kryger quotes then-President Obama as saying that when his term ended, “I’m going to take three, four months where I just sleep.” Kryger said that insufficient sleep can be risky in presidents, because it may cause irritability and impulsivity.

As for Kryger himself, he usually manages to get at least seven hours of sleep. He recommends heeding a colleague’s caveat: “If you don’t sleep, you don’t dream.”