00:01
Hi there!
Let’s do sleep.
00:05
The stages of sleep are defined by
the following EEG characteristics,
electroencephalogram.
00:13
Defined as REM versus non-REM and
I’ll give you the details as to
what exactly that encompasses.
00:20
Typically, cycle in an orderly
fashion over a 90-minute period.
00:25
Four to six cycles per
night in young adults.
00:29
And REM density decreases
as we age, unfortunately.
00:34
Stage 2 density increases to
replace the REM as we age.
00:40
Let’s take a look at all
of this in greater depth.
00:44
Here, we’ll take a look at non-REM cycle
sleeps and their respective stages.
00:49
Stage 1, loss of posterior
alpha rhythm on EEG,
typically a brief
transition stage.
00:56
So stage 1, brief.
00:59
Stage 2: You have sleep spindles
and K-complexes on EEG.
01:06
Make up the majority of your
sleep in adults, stage 2.
01:10
And as I was telling you earlier,
remember that REM starts
diminishing as we get older,
replaced usually by
stage 2 more so.
01:17
K-complexes.
01:19
Stage 3 will be 20 to 50%
of EEG and delta activity.
01:25
And what that means to you on
your EEG is 4 hertz or less.
01:31
Remember, all characterized by
reduced but present muscle tone
and regular, slow respirations.
01:39
REM sleep is what’s next.
01:43
The EEG very much looks similar
to that of wakefulness.
01:48
Rapid eye movement is what REM
stands for, horizontal in fashion.
01:54
Irregular respirations,
loss of skeletal muscle tone,
except for the eyes and larynx.
02:02
It has to, so you can breathe
and so that you can have the
rapid eye horizontal movements.
02:07
Vivid dreams.