Why aren't you asleep yet? A bedtime story - includes related information

FDA Consumer, Oct, 1989 by Egon Weck

Why Aren't You Asleep Yet?

A BEDTIME STORY

Every night millions of Americans toss in their beds, restless and wakeful. Some sleep specialists suggest that as many as 35 million Americans suffer from insomnia.

Although sleeplessness is not thought of as a life-and-death problem, 14 members of a family in Bologna, Italy, have died as a result of chronic insomnia since 1922, according to a report by neurologist Elio Lugaresi, M.D., in the Oct. 17, 1986, issue of the New England Journal of Medicine. Lugaresi says that the last victim, a 53-year-old man, died after going without sleep for nine months.

Although deaths ascribed directly to insomnia are extremely rare, accidents--including traffic fatalities -- indirectly attributed to disturbed sleep have been the subject of research for more than 20 years, according to James W. Danaher, chief of the Human Performance Division of the National Transportation Safety Board.

The fragmented slumber of sleep apnea patients, for instance, shows up in a deterioration of physical and mental performance. (People with sleep apnea stop breathing during sleep for brief periods, causing them to awaken repeatedly, gasping for air.)

In two studies of sleep apnea victims, one group was found to have a higher rate of traffic accidents and another performed much below average on driving tests.

"Some of these people are almost sleep-walking," observes Martin Cohn, M.D., director of the Southwest Florida Sleep Center, who studied sleep disorders at Mt. Sinai Hospital in Miami Beach. "Their reflexes are slower, they may miss red lights and present other driving dangers. Inattentive, they may make frequent mistakes and appear lazy and indifferent, causing employers to fire them."

Besides their concern for motorists, researchers studying the link between disturbed sleep and accidents are becoming increasingly aware of the adverse effects of sleep deprivation on airline pilots, railroad engineers, and others whose performance affects public safety. "There is a growing national interest in the effect of the quality of sleep on next-day performance," says Cohn.

Sleep and Immunity

Animal studies suggest a link between sleep and the immune system, and research scientists have identified chemicals made in the human body that foster sleep but also have a role in the healing process. For example, one chemical called factor S stimulates the production and release of interleukin-1, which helps the body fight disease.

Summarizing current research on sleep and the immune mechanism, researcher James M. Krueger of the University of Tennessee in Memphis, says that there seems to be a multi-feedback system working on channels tied to both sleep and the immune system. "Sleep and the immune response seem to be so interwoven that sleep may eventually be recognized as a component of the body's infection-fighting mechanism," Krueger concludes.

Many Symptoms and Causes

With sound sleep so important, how much is enough? Individual needs can vary greatly. For most adults, seven to eight hours is enough. Older people generally seem to need less after age 60--they get along with five or six hours of sleep per day. Babies, on the other hand, normally require 16 to 17 hours.

Insomnia has a variety of causes, ranging from physical ills to the emotional stress of grief or anxiety. It may also be traceable to psychiatric problems.

There are no hard and fast criteria that define insomnia. The duration and depth of sleep can vary so greatly among individuals that it may be difficult to decide what is enough in each case. For example, some persons who sleep more than six hours may feel they haven't slept enough.

Some signs of insomnia include: * difficulty falling asleep, taking more than a half hour--several hours in some cases--to fall asleep, * awakening several times during the night, and * awakening early, or sleeping less than four hours a night.

Researchers have observed that sleep patterns change with age and sleep problems occur more frequently in the elderly. After 60, people have more trouble falling asleep, awaken more often, and, once awake, find it more difficult, if not impossible, to drop back into sleep.

Sleep Cycles

Each sleep cycle is characterized by two principal types of sleep--rapid eye movement (REM) and non-REM (NREM) sleep. NREM sleep is further subdivided into four stages that can be differentiated by electroencephalography (a recording of electric currents developed by the brain). Brain wave tracings during NREM sleep decrease in frequency and increase in amplitude as sleepers move from stage 1 to 4--the last being the most restful. Stage 1 marks the transition from wakefulness to sleep. Stage 4 (delta sleep) is accompanied by slow heart rate and breathing and deep muscle relaxation.

A comparison of sleep cycles published in the New England Journal of Medicine in 1974 reveals significant differences between the sleep patterns of young adults and older people. During a normal night's sleep, young adults go through four to six cycles of combined NREM/REM stages lasting from 60 to 90 minutes each. They may awaken two or three times in the course of a night but be unaware of it. About 90 minutes after falling asleep, or soon after stage 4 is reached, young adults go into REM sleep, a period of dreaming and, in men, penile erection.