Getting enough restful sleep restores the mind and body, preparing both for the challenges that lie ahead. Without it, mood, concentration, and mental performance suffer. And according to research reported in the February 2012 Harvard Men’s Health Watch, sleep may actually improve cognitive function. These findings suggest that even a brief nap may help boost learning, memory, and creative problem solving.
Sleep is divided into two major phases, rapid-eye-movement (REM) and non–rapid-eye-movement (NREM). Sleep begins with the NREM state, which lasts about 60 to 90 minutes, before REM sleep kicks in. Dreaming is most common during REM sleep, but it may also occur during the early stages of NREM sleep.
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