Fitful sleep, restless nights, hitting the alarm clock button for an additional 10 minutes of sleep—all are all too familiar manifestations of the interactions of life with one of the frontiers of science and clinical practice—somnology1 and sleep medicine. It is estimated that 50 to 70 million Americans suffer from a chronic disorder of sleep and wakefulness (NHLBI, 2003), hindering daily functioning and adversely affecting health. The current capacity of America’s health system is not sufficient to diagnose and treat all individuals with sleep disorders. Further, awareness among health care professionals and the general public is low considering the size of the problem. Among those individuals with sleep disorders are 3 to 4 million individuals with moderate to severe obstructive sleep apnea (Young et al., 1993), a disorder characterized by brief periods of recurrent cessation of breathing caused by airway obstruction with morbid or fatal consequences. Chronic insomnia, which hampers a person’s ability to fall asleep, is observed in approximately 10 percent of the American population (Ford and Kamerow, 1989; Simon and VonKorff, 1997; Roth and Ancoli-Israel, 1999). Restless legs syndrome and periodic limb movement disorder are neurological conditions characterized by nocturnal limb movements and an irresistible urge to move the legs. These conditions affect approximately 5 percent of the general population (Lavigne and Montplaisir, 1994; Rothdach et al., 2000; NSF, 2000; Montplaisir et al., 2005), making it one of the most common movement disorders (Montplaisir et al., 2005).

The negative public health consequences of sleep loss and sleep-related disorders are enormous. Some of the most devastating human and environmental health disasters have been partially attributed to fatigue-related performance failures,2 sleep loss, and night shift work-related performance failures, including the tragedy at the Union Carbide chemical plant in Bhopal, India; the nuclear reactor meltdowns at Three Mile Island and Chernobyl; and the grounding of the Exxon Valdez oil tanker (NCSDR, 1994; Moss and Sills, 1981; United States Senate Committee on Energy and National Resources, 1986; USNRC, 1987; Dinges et al., 1989). Each of these incidents not only cost millions of dollars but also had a disastrous impact on the environment and the health of local communities.


Somnology is the branch of science devoted to the study of the physiology of sleep, the behavioral dimensions of sleep, and the consequences of sleep loss and sleep disorders on an individual’s and the general population’s health, performance, safety, and quality of life. Sleep medicine is the branch of clinical medicine devoted to the diagnosis and treatment of individuals suffering from chronic sleep loss or sleep disorders.


A significant portion of fatigue, but not all, is caused by chronic sleep loss and/or sleep disorders.

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement