how long do our sleep cycles typically last during a typical night's sleep
When Does REM Sleep Occur? Slow wave sleep comes mostly in the first half of the night, REM in the second half. REM sleep typically begins about 90 minutes after you first fall asleep, with the first REM cycle lasting about 10 minutes. Each successive REM cycle last longer, with the final REM stage lasting up to 1 hour. Most people experience three to five intervals of REM sleep each night.