Normal Sleep
Everyone needs sleep. Two thirds of the people in North America will complain about sleeping problems at some time in their life. There are over 80 different types of sleep disorders.
There are 2 stages of sleep:
- non-rapid eye movement sleep (NREM)
- rapid eye movement sleep (REM)
NREM Sleep
This is the type of sleep when you don’t dream. You do some thinking in NREM sleep, but it is usually simple and broken into parts. There are 3 stages of NREM sleep:
- stage N1 sleep: This is when you go from being awake to being asleep. This type of sleep doesn’t restore your body. Although you may be asleep, you may also still be partially awake.
- stage N2 sleep: This is deeper than stage 1 and may help your body recover.
- stage N3 sleep: This is also called delta sleep. Delta sleep is a very deep sleep that helps your body restore and recover.
REM Sleep
REM sleep is the type of sleep when you dream. Your eyes move very fast, which gives this type of sleep its name. During REM sleep, your muscles can’t move. You can only move your eyes and breathe in this stage of sleep.
In most people, REM sleep happens every 90 minutes throughout the night. The first REM period may only be 5 minutes long. The second is about 10 minutes long and the third is about 15 minutes long. For most people, the last dream of the night can last for 30 to 60 minutes. You may or may not remember dreaming, but everyone dreams.
The graph below shows what a normal sleep looks like. You normally enter stage N1 sleep and then work your way into the deep stage N3 sleep. REM sleep follows this. The person from the graph below had 5 periods of NREM and REM sleep (sleep cycles) during the night.
