Dr. Matt Walker

And for all of the years of work that we've been doing in this field, and I've spilled so much ink over this, including in the book, he summarized it in a single sentence.

And it's something that we started off trying to test with one specific belief.

And then we were beautifully course corrected by the data and

We thought that the hinge was going to be once you were sleep deprived and you started to slide down into that fight or flight branch, the more sympathetic and away from the parasympathetic, that the hinge would get ever tighter, the further into that sympathetic stress-related fight or flight dip that you had, and there you would stay.

It wasn't quite that simple.

What we found was that when I challenge you or put you either under a very simple cardiovascular challenge, let's say I'm just having you grip a bar for a long period of time, or we have you under some other, maybe even if it's an exercise regimen,

when you are in a sleep deprived state and you are largely inert and not interacting with the world, you actually are in a more strong parasympathetic state.

it's almost as though you do not want to interact with the world per se.

And this comes on to motivation.

We and others have found that one of the earliest and strongest effects of a lack of sleep is just absence of motivation.

I don't want to interact with the world.

I don't want to be social.

I don't want to learn.

I don't want to exert effort.

I don't want to exercise.

I just don't want to do much of anything.

However, when you provoke me and you force me to interact or there is a very strong emotional event that I experience, I go all the way over into the strongly sympathetic.

So it's almost as though...

We had the prediction that there was going to be a very tight hinge and the screw was tightening the more sympathetic you became.

It was much more that you were in this sort of parasympathetic state, this sort of non-motivational state.