Objective Correlates of the Refreshing Effects of Sleep

Abstract

This chapter discusses an investigative study conducted to establish certain objective correlates of refreshing and unrefreshing sleep. Two groups consisting of 11 emotionally stable, and 11 emotionally labile subjects were selected from a larger sample of 127 randomly selected male students. Differentiation of these two study groups was made by a measure of emotional stability-lability established through factorial analyses of questionnaire data, body measurements, and measures of autonomic functions. In the investigation, average depth of sleep as evidenced by electroencephalogram (EEG)criteria failed to differentiate the two study groups. Findings of the present study, however, indicated that emotionally labile subjects manifest more movements of facial muscles during sleep, and as shown by actographic recordings, they display less body movements and less pronounced body movements during sleep than emotionally stable subjects. Multiple correlations of these indices with the questionnaire-scale utilized to assess subjective feelings of freshness following sleep yielded a highly significant coefficient of 0.80. Based on the results, objective correlates of sleep subjectively reported to be refreshing consist of minimal movements in facial muscles and a maximum of pronounced body movements during sleep. As measured by EEG potentials, depth of sleep appeared to be unrelated to the degree of freshness on waking.