What are the stages of sleep?
As you slumber, you move through four sleep stages, each of which is characterized by changes in the brain and body. Going through each of these stages consists of one sleep cycle.
The sleep stages
The four stages of sleep are:
- Stage 1 — Your body begins to transition into sleep. Your breath, heart rate, and brain waves slow down, and your muscles start to relax.
- Stage 2 — Different processes in your brain and body continue to slow, and your body temperature drops, in this light sleep stage.
- Stage 3 — Your breath rate, heart rate, and brain activity drop to low levels. This is the deepest sleep stage.
- Rapid eye movement (REM) sleep — Your eyes move quickly, brain and body processes become quicker, and dreaming occurs.
How often do we cycle through the sleep stages?
In one night, your brain typically goes through each sleep stage four to six times. Each sleep cycle lasts an average of 75-90 minutes.