What Are REM and Non-REM Sleep?
In this article
- What Happens During Non-REM Sleep?
- What Is REM Sleep?
A lot
happens in your body while you sleep. When you get your ZZZs, you cycle between
REM and non-REM sleep.
REM
stands for rapid eye movement. During REM sleep, your eyes move quickly in
different directions. That doesn't happen during non-REM sleep.
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First
comes non-REM sleep, followed by a shorter period of REM sleep, and then the
cycle starts over again. Dreams typically happen during REM sleep.
There are
three phases of non-REM sleep. Each stage can last from 5 to 15 minutes. You go
through all three phases before reaching REM sleep.
Stage 1: Your eyes are closed, but it's
easy to wake you up. This phase may last for 5 to 10 minutes.
Stage 2: You are in light sleep. Your heart
rate slows and your body temperature drops. Your body is getting ready for deep
sleep.
Stages 3: This is the deep sleep stage.
It's harder to rouse you during this stage, and if someone woke you up, you
would feel disoriented for a few minutes.
During
the deep stages of NREM sleep, the body repairs and regrows tissues, builds
bone and muscle, and strengthens the immune system.
As you
get older, you sleep more lightly and get less deep sleep. Aging is also linked
to shorter time spans of sleep, although studies show you still need as much
sleep as when you were younger.
What Is REM Sleep?
Usually,
REM sleep happens 90 minutes after you fall asleep. The first period of REM
typically lasts 10 minutes. Each of your later REM stages gets longer, and the
final one may last up to an hour. Your heart rate and breathing quickens.
You can
have intense dreams during REM sleep, since your brain is more active.
Babies
can spend up to 50% of their sleep in the REM stage, compared to only about 20%
for adults.
Source: WebMDMedical Reference
