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Peter is a writer and editor for the CNET How-To team. He has been covering technology, software, finance, sports and video games since working for @Home Network and Excite in the 1990s. Peter managed ...
Sleep happens in cycles that include three non-rapid eye movement (NREM) stages and one rapid eye movement (REM) stage, repeated 4 to 5 times nightly. Each cycle typically lasts 90 to 110 minutes. The ...