Yeah, the findings that I think are overlooked tremendously are the following experiment.

There's an experiment in animals where a rat is given the opportunity to run on a treadmill and rats and rodents of all kinds love running on treadmills.

You know, there are these interesting, we'll see who catches this fly first.

Yeah, I'm ready, man.

Yeah.

I think, you know, there's even a study from Hoppy Hofstra's lab at Harvard that showed if you put wheels, running wheels in fields, that rodents will run there in the middle of the night and run on them.

That's how insanely obsessed with running.

They're just energetic, they want to go.

There's something rewarding about it for them.

But in any event, it lowers their blood pressure, it leads to improvements in a number of metrics that you expect.

And you see the same thing in humans, right, who run on a treadmill or run outdoors or swim in cardiovascular exercise.

Okay, well, Sapolsky and I love to talk about an experiment where they took two different cages with animals.

One is running voluntarily, but then that running wheel is tethered to a running wheel in another cage that encloses an animal, forces it to run every time the other one runs.

So forced exercise versus voluntary exercise.

And the takeaway is very straightforward.

Voluntary exercise leads to all sorts of improvements in health metrics, resting heart rate, blood pressure, blood glucose, resting blood glucose, et cetera, waking blood glucose.

The animal that's forced to exercise, you see the opposite, right?

So it's not exercise per se, it's something about being forced to exercise causes decrements in a number of health metrics.

And you see the same thing in humans.

So what's wild is my colleague, Dr. Ali Crum, Department of Psychology at Stanford has done these beautiful experiments on mindset and belief.

These are not placebo effects.

And what she's shown in a just absolutely spectacular way is that if people watch a short video about all the ways in which stress can really diminish your health, well then indeed stress diminishes their health.

Whereas if a separate group watches a factual, also five minute, also factual tutorial on all the ways that stress can enhance performance by harnessing your ability to focus, memory formation, et cetera, all of which is true, that's indeed what you see.

Can I give you my favorite one that I learned about over the last year?

So the Boston Marathon bombing, 2012, about 10 years ago, 2016 maybe.

Anyway, Boston Marathon bombing, a study was done comparing people who had been at the actual marathon while the bomb had gone off and people who had watched 90 minutes or more of news coverage about it.

And the people who watched 90 minutes or more of news coverage about it showed a greater stress response than the people who literally lived through it.

IAN Interesting.

Interesting.

Yeah.

The mindset and belief effects are absolutely extraordinary and very real, right?

I mean, I think recently I've been reading and researching a lot about and did a podcast on tenacity and willpower.

And there was this idea early on from Baumeister and colleagues that willpower is a They showed that replenishing glucose in between hard tasks could restore willpower.

IAN They showed that, was it juries or judges that were low in blood glucose were more likely to give harsher sentences, stuff like this.

CARL Yeah, it sort of wicked out to a number of naturalistic situations and it made good sense.

And then my colleague, Carol Dweck, also in the psychology department at Stanford, most famously known for her work on growth mindset, did an experiment in which they essentially asked whether or not tenacity and willpower are limited in terms of being some sort of resource and also whether or not it was somehow linked to glucose availability fuel in the brain and body and found that if people thought or were told that excuse me, willpower was a limited resource, that's indeed what they observed experimentally, but that if they were taught or were told that willpower is unlimited and divorced from glucose levels, well, then that's exactly what you saw.

IAN So you're saying that learning about ego depletion and believing that willpower is a limited resource is an information hazard that is self-fulfilling.

CARL Potentially.

Now Baumeister showed himself to be pretty determined, went and countered the Dweck counter by showing that if indeed, if there's a hard task followed by a hard task, then your beliefs about willpower can impact your performance on the second task.

So Dweck, AKA Dweck is right.

But that if you have a hard task, hard task, and then another hard task, so back to back to back tasks or more, which is a lot of what life is like, well, then it seems that the willpower is a limited resource and glucose supporting willpower theory holds up a bit better.

IAN What have you come to believe about the difference between willpower and motivation and discipline?

How do kind of all of these fit together in your mind?

CARL Yeah, so willpower and tenacity are related to motivation, but they're not quite the same.

I think we should think of motivation as the verb state that moves us from, let's just say apathy to tenacity.

Okay, so it's the verb function that moves us along that continuum, apathy at one end, tenacity and willpower, strong exertion of willpower at the other end.

One of the most interesting structures in the entire nervous system is one that gets very little coverage, unfortunately.

In fact, most neuroscientists aren't aware of what its function is, and it's called the AMCC, which is the anterior mid-cingulate cortex.

You have one on each side of the brain.

The name isn't really important, but we want to, to the credit of the structure, we should name it the AMCC.

The AMCC receives inputs from a lot of interesting brain areas related to reward, related to autonomic function, so how alert or sleepy we are, to prediction, to prediction error.

It's a hub for many, many inputs and outputs, hormone systems, et cetera.

Beautiful experiments done by my colleague, Joe Parvizi at Stanford have shown that if you stimulate this brain area, a tiny little brain area in a human, they immediately feel as if some challenge is impending, and they're going to meet that challenge.

It's a forward center of mass against challenge response.

This has been seen in subjects.

They do controls where they then tell them they're stimulating, but they're not actually stimulating.

And they're like, I don't feel anything.

You can turn on and off tenacity and willpower.

So there's literally a hub for this.

Now here's where it gets really interesting.

I'm going to list off a bunch of peer-reviewed published results in rapid sequence.

And I'm happy to point out the substantiation for this or the references.

Okay.

Individuals that are dieting or resisting some sort of tempting behavior and are successful in doing that, the size and activity in their AMCC goes up over time and the structure gets bigger.

Dieters who fail, flat or downward trajectory of the size and activation of the AMCC.

This can be taken too far.

Individuals with anorexia nervosa, the most deadly of all psychiatric disorders where a self-deprivation of food activates excessive reward.

There's this kind of loop of reward.

Their AMCCs are significantly greater size than others.

So there's, you know, this can be taken too far.

Super agers, which is a bit of a misnomer because these individuals are people who maintain healthy cognitive function, similar to people in their twenties and thirties into their seventies, eighties, and nineties, their AMCC maintains or increases in size into their later years.

Typical agers, the size of, we always hear that you lose brain mass across your lifespan.

Well, most of it is from the AMCC and beautifully.

And this is two of my favorite results that really bring this around to a protocol or a takeaway.

If people are given an easy task, the AMCC isn't activated.

If they're given a hard task, in particular, a hard task, physical or cognitive that they really don't want to do, the AMCC levels of activity go through the roof.

And here's, what's really cool.

They gave aging, what's, you know, people age 60 to 79, the task of adding three hours extra per week of cardiovascular exercise.

Now that's a lot, right?

Three, one hour, they call them aerobic classes, but getting their heart rate up to about 65, 70% of maximum.

So it's getting into like zone three area.

Yeah.

People can look up zone three, but you nailed it.

Zone three, the size of their AMCC increased across that six month protocol and offset the normal age-related decline in this, in this brain area in terms of its size.

The theory that's starting to emerge is that the AMCC isn't just about tenacity and willpower to push through hard things, that it may actually be related to one's will to live, one's will to continue living.

And I think this is, these are some of the most important results.

By the way, I didn't participate in any of the research that I just described.

I spent a lot of time with that literature, but I think it's so important.

I mean, we hear about the amygdala, the hippocampus, the prefrontal cortex, all of very important brain structures, but if nothing else, hopefully this conversation put the AMCC on the map.

The one that literally could create your will to live is the one that's being overlooked a little bit.

And it can be, and what's interesting about this structure is that it's involved in generating tenacity and willpower for all things, not just for one situation.

And what's really wonderful, I think about the research literature on this is it's so clear what we need to do.

We need to do things.

Let's say like me, you're a person who weightlifting and you love running.

I love those two activities.

Well, guess what?

Those activities, even if they're hard, like a hard run that I'm really enjoying or some hard sets in the gym, not going to increase the size or activity of the AMCC.

People love to over romanticize the utility of those final two reps.

Sure.

Okay.

Pushing to failure.

Great.

You know, running hard until your lungs burn.

Great.

But if you enjoy that, you're not increasing your amount of tenacity and willpower, at least according to the research data.

What's going to do it is doing something, what I call micro sucks or macro sucks, you know?

And so micro sucks could be all the little things that you don't want to do during the day.

Macro sucks could be the larger things, but of course, you don't want to do things that are going to damage you psychologically or physically, of course, of course, but everyone, I believe would benefit from picking a few micro sucks.

What are some of your micro sucks or macro sucks that you could sprinkle throughout the day?

Okay.

So on a household maintenance level, you know, I maintain a very clean home.

I'm constantly throwing things away as well, but there are a few things like once I exceed a certain number of dishes in the sink, it becomes this, okay, I'll, I'll load the dishwasher later type thing.

Like a micro suck for me would be like, especially if something's been in there for a while and it's kind of gross and then you got to like work through it.

And of course I try and put each dish away as, as I, you know, dirty them up.

But so little things, the things that the, I really don't want to deal with that right now.

That's the kind of thing, those harder tasks where you have to breach some barriers, some resistance to put it into, you know, Steven Pressfield language or our friend David Goggins, right?

You know, this idea that one has to callous the mind.

I mean, David said that, right?

He's probably got a hypertrophied AMCC that's bigger than most people's.

Probably.

And, and the beauty of having a, an AMCC that's highly, you know, the micro and the macro sucks of the day, you, you have this thing, it's like an engine that you can devote to other things.

So then you can devote the AMCC to other endeavors.

I have this thing I called email anxiety, and it's when my unread inbox reaches three figures or more.

And that's when it just, it kind of follows me around like a poltergeist throughout the day.

And that, that absolutely for me, that's probably a macro suck, you know, to get through that, it's probably three to four hours.

A lot of it's scheduling.

When's this guest coming on?

I need to speak to this partner.

We go blah, blah, blah.

So yeah, I've, I feel that.

What else?

It's subjective, right?

I mean, what's a, what sucks is subjective.

Someone else might love emails.

Yeah.

Someone might.

And, and I think that, you know, you've talked a lot on your show with various guests about, you know, when we're in too much comfort, we're not meeting our goals.

I love deadlines for that reason.

I love deadlines.

I love pressure.

I think, I think Parkinson's law is as close to a thermodynamic of productivity as we can get.

Do you know what I mean?

Like when you have a deadline, you will meet it.

Right.

If you do not have a deadline, you will manana manana until forever.

That's right.

And some people I think preload the deadline by procrastinating.

And then that's what, you know, gets their activation energy to a level where they can, they can engage.

So I've started thinking about this a lot lately, you know, I love running, but it's interesting.

I like to finish it my driveway and I live on a hill.

And actually this morning I was out for a run and the gate at the end of the cul-de-sac is my sort of designated stop point.

So it actually sucked to do the last, you know, 20 meters this morning.

So there, I probably got a little bit of AMCC activation because everything was, the number of negotiations I went through when I turned up my street at the end of this run, whether or not I was going to run this extra 20 meters was ridiculous.

I mean, the human brain struggling to not do this extra 20 meters.

It was so silly.

So it's gotta, it's gotta hurt a little bit.

Again, you don't want to damage yourself, but I think in the context of for instance, cognitive learning, getting to the point where you finish something and then forcing yourself to do one little extra bit there at the end.

So, you know, I, I've, I'm not looking for any credit for it, but I want to be very clear that the scientific literature doesn't call these things micro-sucks.

I call them micro-sucks.

And I sort of put that out there just to make it clear as to what we're referring to.

Do you know Nick Bear? In Austin, he's an athlete and supplement company owner. Yeah, yeah, yeah.

Like a hybrid athlete.

He's a larger guy, but he runs really fast.