We welcome you to our beautiful city! This is truly an exciting time for Worcester. Major investments in transportation improvements such as roadway network reconstruction projects and the provision of commuter rail service at the magnificently renovated Union Station are generating new economic activity.
Since the early 20th century, human sleep has been described as a succession of five recurring stages: four non-REM stages and the REM stage. (A sixth stageârelaxed wakefulness, the phase during which a person falls asleepâis sometimes included).
Slow-wave sleep. Slow-wave sleep (SWS), often referred to as deep sleep, consists of Stage three (combined stages 3 and 4) of non-rapid eye movement sleep. Initially, SWS consisted of both Stage 3 (N3), which has 20-50 percent delta wave activity, and Stage four (N4), which has more than 50 percent delta wave activity.