What is REM Sleep? There are five stages of sleep, four of which are NREM (non-rapid eye movement) sleep, and one of which is REM (rapid eye movement) sleep. The four stages of NREM sleep are: Light sleep – easily interrupted, usually lasts 1-7 minutes Deeper sleep – more difficult to wake from, usually lasts 10-25 minutes Slow-wave sleep – usually occurring during the first third of the night Slow-wave sleep – most difficult to wake from, lasts 20-40 minutes REM sleep – dream activity, increased heart rate, rapid, irregular breathing patterns These five stages of sleep last for different […]