Let’s do sleep.
The stages of sleep are defined by
the following EEG characteristics,
Defined as REM versus non-REM and
I’ll give you the details as to
what exactly that encompasses.
Typically, cycle in an orderly
fashion over a 90-minute period.
Four to six cycles per
night in young adults.
And REM density decreases
as we age, unfortunately.
Stage 2 density increases to
replace the REM as we age.
Let’s take a look at all
of this in greater depth.
Here, we’ll take a look at non-REM cycle
sleeps and their respective stages.
Stage 1, loss of posterior
alpha rhythm on EEG,
typically a brief
So stage 1, brief.
Stage 2: You have sleep spindles
and K-complexes on EEG.
Make up the majority of your
sleep in adults, stage 2.
And as I was telling you earlier,
remember that REM starts
diminishing as we get older,
replaced usually by
stage 2 more so.
Stage 3 will be 20 to 50%
of EEG and delta activity.
And what that means to you on
your EEG is 4 hertz or less.
And then stage 4, greater than
50% of EEG would be then delta.
Remember, all characterized by
reduced but present muscle tone
and regular, slow respirations.
when we breathe at night or, excuse
me, when we breathe when we sleep,
because of the lower
you should remember that there is a
possibility that respiratory acidosis
is a common and
REM sleep is what’s next.
The EEG very much looks similar
to that of wakefulness.
Rapid eye movement is what REM
stands for, horizontal in fashion.
loss of skeletal muscle tone,
except for the eyes and larynx.
It has to, so you can breathe
and so that you can have the
rapid eye horizontal movements.