Kleitman, Nathaniel, 1895-

Nathaniel Kleitman, recognized as the father of modern sleep research, served on the faculty of the University of Chicago's Department of Physiology. His papers include notes, experiment data, drafts of articles and books, academic reprints, newspaper clippings, photographs, artifacts and audio-visual recordings.

Nathaniel Kleitman was born in Kishinev, Russia in 1895. He came to the US in 1915 and earned his B.S. degree four years later from what is now City College in New York. In 1920 he received his M.A. from Columbia University. After two years as an instructor in physiology and pharmacology at the University of Georgia, he returned to graduate school and earned his PhD in physiology from the University of Chicago in 1923. From then until 1925, a National Research Council Fellowship allowed him to study at the University of Utrecht in the Netherlands and the University of Paris. In 1925 he became a faculty member in physiology at Chicago, where he would spend the next 35 years, until his retirements as a full professor in 1960.

Dr. Kleitman was the first scholar to concentrate entirely on sleep research and is internationally recognized as the founder of his field. In 1939, the University of Chicago Press published his collection of sleep studies, Sleep and Wakefulness (revised in 1963 and 1987), which became the foundational text for sleep research.

Dr. Kleitman, his assistants, students and even family were themselves subjects in many of his early sleep experiments. In an effort to see if human subjects-namely, himself and an assistant, Bruce Richardson-could adapt to a 28-hour day, they lived in Mammoth Cave for over a month in 1938. Since the temperature in the cave was perpetually 54 degrees and there was no natural light, there were no environmental cues to the time of day. Though Dr. Kleitman could not sleep until 10 pm surface time, Mr. Richardson adapted. In the cave, Dr. Kleitman measured body temperature and discovered that there was a slight but regular fluctuation throughout the day, and that peak efficiency occurred while the body temperature was highest. He later applied this knowledge to recommendations that soldiers and industrial staff work regular shifts so that their bodies could adjust to a 24 hour cycle, allowing them to stay more alert than if they continually switched shifts.

His research took Dr. Kleitman to other unusual places. In 1948 he spent two weeks on a submarine, the U.S.S. Dogfish, studying the effects of mental alertness as a result of temperature changes. He recommended a system of watch scheduling that took into consideration the normal patterns of sleep and body temperature, arguing that too many men went on duty when their body temperatures and alertness were low. He also once traveled to Tromso, in northern Norway, to see if inhabitants of the Artic Circle, where winter plunges the sky into months of darkness while summer brings unending daylight, slept on a different schedule. The answer was no.

The discovery of rapid-eye movement (R.E.M.) sleep came in 1953. Dr. Keitman and his student Dr. Eugene Aserinsky recorded regular periods of jerky eye movements during sleep. They also showed that people who were awakened in

this period, recalled having dreams, while those awakened in non-R.E.M sleep did not. The discovery of R.E.M., in addition to Kleitman's other sleep research, eventually led to a much greater understanding of the sleep process in general and to the discovery of sleep disorders.