How long does a typical adult sleep cycle last?

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A typical adult sleep cycle, which includes both NREM and REM phases, lasts approximately 90 to 110 minutes.1

During a normal night's sleep, adults typically complete this cycle four to six times. While the duration of these ultradian cycles remains roughly equivalent throughout the night, the composition of the stages within each cycle shifts: the REM portion tends to lengthen as the night progresses, while the contribution of deep NREM sleep (stage 3) decreases.21