On average over a 7-9 hour night of sleep, we go through 4-6 cycles of sleep.

During these cycles there are two different kinds of sleep, NREM (non-REM) and REM (Rapid Eye Movement). Deep sleep consists of both NREM sleep and REM sleep, taking place in stages 3 and 4 of the sleep cycle.

Deep sleep is important because these are the stages where your mind and body recharge from the day. Stage 3 of the sleep cycle allows your body to recharge while stage 4 helps with your cognitive functions too. Without these stages of sleep, our thinking would suffer along with our mental and physical health.