Dr. Michael Grandner

So the fact that you can get that close from this stuff on the wrist, I think is a miracle, but you got to keep your expectations in check.

It's like playing two games of telephone going in opposite directions and using the result of one game of telephone to guess not what the source was, but what the other game of telephone came up with.

So the fact that they're even in the same ballpark, I think is great and useful.

But what that also means is,

don't read too much into it.

Like if you, if it shows very little deep, first of all, I can't distinguish stage one and stage two at all.

So they call it light usually.

And as I mentioned before, those are very different things.

If you have a lot of stage one, that's bad because your sleep is super shallow.

You have a lot of stage two, that's normal.

That's what should be most of what sleep is.

And the deep sleep detection is only about 60 to 70 percent accurate at best in most people.

So when people say like it's not showing I'm getting enough deep sleep, I say, well, the algorithm isn't picking it up.

It doesn't mean you're not.

It doesn't mean you're not getting it.

And B, if you weren't.

As long as there's no barrier to your body obtaining, if you don't have untreated sleep apnea or chronic pain or an environmental stimulation to prevent that deep sleep from occurring or drinking alcohol or whatever, your body is doing whatever it wants to do.

So if it doesn't want to take more, because as people get older, they take less anyway, you know, growing people, healing and recovering people usually need more, but

If you're not getting it, A, does it matter?

And B, how do I know you're not getting it?