<i>Sleep and Variations in Certain Functional Activities Accompanying Cyclic Changes in Depth of Sleep</i>

Multiple recording has been employed to identify and quantitate sleep and detect functional changes associated with variations in sleep of men and women.

Abstract

Multiple recording has been employed to identify and quantitate sleep and detect functional changes associated with variations in sleep of men and women. Long periods of uninterrupted deep sleep occurred most frequently early in the night. However, the average estimated depth of sleep was similar during the first and second halves of the night. Intervals of lessened sleep were often associated with cardiac acceleration, greater variation in cycle length and body movements but average depth of sleep did not correlate with average heart rate or number and duration of movements. Persons who slept most deeply moved less often, wakened less frequently and showed less variation from night to night. Motility was greater during the latter half of the night in five of six subjects. Variation in toe temperature, frequency of sleep cycles and numerous other changes recorded did not correlate well with depth of sleep estimated from electroencephalographic records. These findings suggest that changes in heart rate or toe temperature from a basal value rather than average nightly values can be used as indicators of the depth of sleep to support interpretation of electroencephalographic tracings. Although movement most often is associated with brief alterations in the depth of sleep and heart rate, fewer or more moves do not necessarily result in better or poorer sleep and relaxation.