Contemporary culture increasingly suffers from problems of attention, over-stimulation, and stress, and a variety of personal and social discontents generated by deceptive body images. This book argues that improved body consciousness can relieve these problems and enhance one's knowledge, performance, and pleasure.
In the R&K standard, NREM sleep was divided into four stages, with slow-wave sleep comprising stages 3 and 4. In stage 3, delta waves made up less than 50% of the total wave patterns, while they made up more than 50% in stage 4. Furthermore, REM sleep was sometimes referred to as stage 5. In 2004, the AASM commissioned the AASM Visual Scoring Task Force to review the R&K scoring system.
Each complete cycle takes about an hour and a half. A group of researchers proposed in 1937 that the cycle be divided into 5 stages identifiable in the EEG record, labeled A through E. Now these stages are labeled 1 to 4, with the fifth being REM sleep. Some researchers refer to the wakefulness before sleep as stage 0.