Dr. Matt Walker

I look at your quantity and does it predict your blood sugar regulation?

I look at your quantity, does it predict your immune health?

I look at your quantity and does it predict your mortality risk?

And the answer has been yes.

that quantity does predict many of those things.

That's great.

What was interesting is that if you look at the statistic of the predictability of quantity alone, it was strong, it was significant, but it still left a lot of unexplained, what we call variants.

So it must be that there are some other things in sleep that are explaining these health metrics in addition to quantity.

And quality has now come online, I think, in the past 10 years as carrying as much, if not perhaps even more, in certain domains of a predictive strength in determining your mental and your physical health, that quantity has.

And it at least forced me in my own research to, A, always be measuring quality in as high resolution as I can and always including it into a statistical model.

And we can do fancy things where we put those two things, you know, pit them head to head and see which one actually holds more of the statistical weight.

But certainly quality sleep is...

is as important, I would say now, at least as important as the quantity of sleep.

Now you can't shortchange on either.

You can't say, okay, did he just tell me that I should not worry about how long I'm sleeping?

So you can't just get four hours of sleep that is incredibly good quality and get away with it.

But you also can't be in bed for nine hours or 10 hours

getting seven hours of sleep, but it's really bad quality of sleep.

You have to get both.

You can't shortchange either one of those.