What Are the Stages of Sleep?

What Are the Stages of Sleep?
A sleep cycle is broken down into two main stages - NREM (non-rapid eye movement) sleep and REM (rapid eye movement sleep). This cycle is repeated about every 90 minutes with NREM sleep accounting for 75% of a night’s sleep.

NREM Sleep (Stages 1-4)

Stage 1 (“Catnap”)
As you begin to nod off, your eye movements decrease, but you’re still somewhat alert and can be woken up easily.

Stage 2 (“Power Nap”)
Your brain waves start to slow down as you become disengaged from your surroundings and your body temperature lowers.

Stages 3 & 4 (“Deep Sleep”)
In these stages, your breathing becomes slower, your blood pressure decreases, and your body begins repairing muscles and tissues as well as restoring your energy level for the coming day. This is the most difficult stage to be awakened from.

REM Sleep (Stage 5)

Stage 5 (“Dreaming”)
Accounting for about 25% of your night’s sleep, REM sleep begins 90 minutes into the cycle and gradually increases in length in each subsequent cycle. The majority of dreaming occurs in this state as your brain becomes much more active, your eyes dart back and forth, and your heart rate and blood pressure increase.
This cycle is repeated five to six times during an average night’s sleep. A cool, comfortable mattress is key to getting enough Deep Sleep!