Dr. Matt Walker

No one responds to rules.

They respond to reasons and not rules.

So let me explain the reasons behind each one of these.

So quantity, we've already spoken about somewhere between seven to nine for the average adult.

Let me move on to quality.

We measure quality in a variety of different ways.

The first principle quality measure of sleep is continuity.

So meaning was your sleep nice and continuous and you didn't wake up many times or was your sleep fragmented and littered with many awakenings?

It was punctuated by these awakenings.

If it's very highly fragmented, that's what we call poor quality of sleep.

That's low efficiency of sleep.

So maybe you would be in bed for, let's say, nine hours,

And you still got seven hours of sleep.

So if all you used was your quantity measure, you would say, well, you've still had good sleep.

You've had seven hours.

But two of those hours have been spent awake, summed total.

So that is very low quality of sleep.

And it's what we would call a low score of efficiency.

So if you're looking at any of your sleep trackers, that's probably best captured by sleep efficiency.

What is sleep efficiency?