Matthew Walker

And you can kind of go into almost like a low battery mode when you're awake,

But in quiet rest, and I think that can drive some already early clearance from the brain.

And then when you go into sleep, it's like powering your phone off entirely.

It truly gets the chance to sort of cleanse and reboot the biochemical system.

But I think it's really interesting.

I think there's a lot of work still yet to be done.

It's not quite as case closed as we used to think.

I think it's really interesting.

And just to come back to your point about the AFib paper, what we know is that this cleansing system in the brain does seem to track the big, slow brainwaves of deep, slow-wave sleep.

But it's not only tracking the big, slow brainwaves.

If anything, there's something to do with the cardiorespiratory cycle, the respiration rate, and the cardiac signal that may actually sync with the brainwaves.

And it's essentially a cardiorespiratory neurophysiological coupling, which is a lot of ways, which is to say heart, lungs, and brain coupled together.

And it's the coupling of the cardiorespiratory slow oscillations that drive these pulsatile fluid mechanical.

It's literally a hydro-mechanical, hydro meaning cerebrospinal fluid,

push and pull in and out of the system, drawing those metabolites out.

So ergo, if you have a disrupted either cardiac or respiratory or neurophysiological signal, no wonder the glymphatic system isn't going to work as efficiently.

I think that's a beautiful demonstration of the...

The hemi-neglect that people like me who study sleep largely from the neck upwards would miss.

But if you think about sleep is not just for the brain, it's for the body.

And it's not just for the body, it's for the brain.