FIGURE 2.30 The stages in a typical night’s sleep People pass through a multistage sleep cycle several times each night. As the night goes on, the periods of deep sleep diminish and REM sleep increases. As people age, sleep becomes more fragile, with awakenings more common (Kamel & Gammack, 2006; Neubauer, 1999).
(Kamel & Gammack, 2006; Neubauer, 1999).