Welcome to the Longevity Blueprint.
I'm Dr.
Linda Friedland.
We've talked about REM,
Your brain's overnight workaholic.
Its counterpart,
Deep sleep,
Also called slow wave sleep,
Is what we're talking about.
This is where your body does its own overnight work.
Deep sleep is concentrated in the first half of the night.
And it's the hardest stage to wake someone from.
Your brainwaves slow to their widest,
Most synchronized pattern of the whole night.
This is when growth hormone is released,
Which drives tissue repair and muscle recovery.
Deep sleep is also when your immune system does much of its strengthening.
And it's where your glymphatic system,
Your brain's own clearing system,
Becomes most active,
Flushing out metabolic waste that's built up through the day.
Including proteins that are linked to long-term brain health and cognition.
As with REM,
Your wearable,
Your watch or anything you use to track isn't watching any of this directly.
It's estimating deep sleep from stillness combined with the same heart rate and HIV patterns it uses for the other stages.
It's genuinely useful as a trend,
But not as a direct window into your brain.
What you can do to enhance deep sleep.
One of the most powerful things is a cool room.
The cool room does more for deep sleep than almost anything else people try.
What's interesting is up till recently,
We've always imagined that you want to get super warm and cozy at night.
But in actual fact,
Quite the opposite.
Your core temperature needs to drop for deep sleep to initiate properly.
And a warm room fights that directly.
Alcohol is worth understanding specifically here.
It can appear to increase deep sleep.
In the first part of the night.
But it really fragments your sleep and it lightens it later on.
More time.
In this light sleep,
Lower quality sleep.
Exercise,
Especially early in the day,
Reliably supports deep sleep that night.
One of the most consistent findings in sleep research.
And a heavy meal close to bedtime works against it,
As digestion competes with the temperature drop your body is trying to make.
Consistent sleep and wake times still matters here too,
Just like with REM sleep.
Deep sleep is concentrated earlier in the night.
So a late bedtime doesn't just shift your schedule.
It can genuinely shrink your deep sleep window.
So let's try a short practice.
Lie back and let your eyes close.
And remember those factors.
Avoid alcohol at night.
Cool room.
Exercise earlier in the day.
Now bring your attention to your feet.
Let them go heavy.
Let that heaviness move up through your legs,
Your hips.
Feel the heaviness.
Moving into your chest and shoulders.
Sinking comfortably into the bed beneath you.
That heavy wave of relaxation.
Moves through your arms your face.
Your body is cool and settled.
It has everything it needs to do its own quiet work tonight.
Cool rim.
Relaxed state.
These are small choices.
And they're exactly the ones that give your body its best shot at the deep sleep it's built to do.
Age boldly,
Live well,
Sleep peacefully.
And feel free to tune in to the other videos on REM sleep.
