Matthew Walker

Not only did it increase sleep,

But it seemed to increase.

Well, the assumption was that it was increasing glymphatic clearance because at least as the end outcome product, there was greater clearance of beta amyloid and tau protein in the blood.

It wasn't just junk sleep.

It was functional sleep.

So for the first time, I'd seen a sleeping medication that increased sleep more naturalistically.

But that increased sleep made you, the organism, function better the next day as a consequence.

Does that make any sense?

Absolutely.

Yeah, I think quantity is what we've been talking about in some ways, but quality has also come onto the radar as absolutely essential.

And what we find is that the quality of your sleep is as if not more predictive of both all cause mortality, cardiovascular mortality, metabolic mortality, and in some regards, cancer mortality as well.

And when I say quality of sleep, what we're really referring to here is at least one of two things.

One is the continuity of your sleep.

You could be sleeping for eight and a half hours according to your sort of sleep tracker.

but maybe you're getting eight and a half hours by spending 10 hours of time in bed because you're awake so much throughout the night and your sleep is very sort of punctured and littered with all of these awakenings across the night.

That's sufficient quantity of sleep, eight and a half hours, but it's poor quality of sleep.

because you're spending too much time awake.

And so our measure of quality of sleep typically is what we call sleep efficiency.

Of the time that you're in bed, what percent of that time are you asleep?

And we like to see some measure of at least 85% or above, because once you get less than 85% in terms of your sleep quality or your sleep efficiency,