If you sit for 10 hours a day compared

to 9 hours a day, it's about a 10%

increased risk of dementia. If you sit

for 12 hours a day, it's about a 60%

increased risk of dementia. 60%? Yes.

So, it's a problem that we have to deal

with. David Raichlen, Professor of human

evolutionary biology, exercise

physiology, and neuroscience.

At the University of Southern

California, we are dealing with brain

health problems that are only going to

increase as our population ages. And

healthy aging is linked to three major

diet, physical activity, and social

connections. For example, people who

have stronger social connections tend to

have better brain outcomes than people

who don't. Does excessive alcohol use

shrink the brain? Yes. Over one drink

per day is associated with negative

health outcomes. Sleep is the other one.

That's a big factor in cognitive

decline, right?

It is. Less sleep and lots of sleep are

both associated with higher risk. Is

there an optimal amount of exercise?

Physical activity guidelines are 150

minutes per week, but only 25% of adults

in the US meet those guidelines with

older adults doing two to four minutes

per day. Two to four? But there are

these small activities that provide big

benefits, that generate new neurons, and

those neurons get integrated into key

parts of the brain. Number one is

Remote work is dangerous.

It's unnatural for the human body. I'm

concerned about physical health. What's

the practical advice to people that work

at home that is realistic for us? If you

combine

with

it will literally change your life.

I think this is fascinating. I looked at

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[Music]

David, if you had to summarize the

essence of what your work shines a light

on, and what it intends to help us

understand as human beings, how would

you summarize that? What my work has

been focused on is understanding how and

why physical activity, especially and

lifestyle behaviors in general, can

impact health and most specifically

impact the health of our brains.

And I think that you know, we are

dealing with

brain health problems that are only

going to increase as our population

ages.

So, we have we have 6 million people in

the US today that are diagnosed with

Alzheimer's disease or other related

dementias. That's projected to grow to

around 13 million people over the next

25 years or so.

It's we're projected to have 150 million

people diagnosed with dementia worldwide

over the next 30 years or so. So, it's a

problem that we have to deal with, and I

my work has been focused on ways that we

can prevent these diseases that are

associated with aging. Why does the

brain matter? And I say this in part

because I think for most of my life I

just assumed

you know, I understand muscles. I can go

to the gym and work on my muscles, but

the brain I just thought is this like

piece of tofu in between my skull that I

have very little control over.

Yeah. I mean, I think that is that was

the prevailing view for a long time

that, you know, we grow our brains as

children and during adolescence, and by

the time you're in your 20s, your brain

has done all the growing it's going to

do, and now it's just this progressive

shrinking over the rest of your life.

And, you know, over the last few

decades, we've realized that's not true,

actually, that you can

generate new neurons, especially in key

areas of the brain like the hippocampus

that's associated with memory, and that

that growth of new neurons may be the

key to preventing or staving off these

neurodegenerative diseases that have

this big impact on aging brain. And so,

you know, if we can find ways to do

that, and and what I study is

kind of doing that through physical

activity and exercise,

then we might be able to prevent some of

the cognitive decline people experience

with aging, maybe even stave off or

prevent the development of Alzheimer's

disease or other dementias. What

evidence have scientists got that we can

actually grow

our brain? Well, that's a great

question.

The evidence in humans is a little

trickier, so I can talk more about the

evidence from animal models because with

animal models you can actually look

inside the brain and see what's

happening after say an exercise

intervention. So, there have now been

many, many studies, especially in mice

and rats, where researchers have shown

that if you give them access to running

wheels, or if you have them run on a

treadmill, that you actually generate

new neurons, and those neurons survive

and get integrated into key parts of the

brain, and we focus a lot on the

hippocampus because it's so important to

memory,

which is a which is a major aspect of

being human is being able to remember

things. And

researchers have shown very clearly that

exercise and physical activity in these

rodent models leads to the birth and

survival of new neurons.

What is a neuron? A neuron is the main

brain cell.

So, a neuron is sort of the main cell in

your brain that's responsible for

communication and transmission of

information across brain regions. And

where you said this hippocampus thing,

which is where I know you referenced

that it's this sort of center point for

memory.

Yeah.

Where is that located in the head? So,

the hippocampus is sort is in the

temporal deep in the temporal lobe of

the brain. It looks like a seahorse, if

you know if it's kind of this curved

curved object in the brain that plays a

big role in different aspects of memory.

So, it plays a big role especially in

working memory, which is

keeping things in your memory over the

short term that you may need to recall

quickly. And it also plays a big role in

the formation of memories of events

that happen in your life, and also in

spatial navigation, which is

an important part of moving around in

the world. So, it's a really key part of

the brain,

and it's also one of the parts of the

brain that is most affected by

neurodegenerative diseases like

Alzheimer's disease. So, it is a part of

the brain that deteriorates in these

diseases, leading to memory deficits

that have a

big effect on your daily life. Is that

the only part of the brain that we're

able to sort of regenerate? Or is it

kind of the rest of the You know, I'm

thinking about these rats and these

mice. If we put them under a brain scan,

would we see the the mass of the brain

increasing?

It's a good question. And is it just

that little seahorse hippocampus part,

or is it the whole brain growing? So, in

in rodent models where

where researchers have done sort of this

detailed work, the hippocampus is where

mainly where new neurons have been found

associated with exercise. In human

studies, brain effects have been more

widespread, so you do see volumetric

changes in the hippocampus, but you also

see volumetric changes or preservation

of brain volume in frontal lobes, which

are associated with executive cognitive

function, so things like planning and

decision-making.

Um Where do we need to begin to

understand

this relationship that humans have

between

exercise and

their brains? There's got to be a point

in history where exercise became

I guess pro-survival in a way, where it

became sort of imperative for us as a

human species to do in order to

preserve and extend our cognitive

capacity, I guess. Yeah, I mean, all

animals generally have to move to

survive, right? They have to move to

find food in some way, but at some point

during human history,

our our pattern of movement shifted

pretty dramatically, and we think that

was around 2 million years ago. And at

that point we shifted from a more

ape-like lifestyle to a hunting and

gathering lifestyle, where our travel

distances increased drastically, so we

were moving over, you know, 20 km

sometimes per day,

sometimes longer,

and our intensity of movement probably

shifted a bit to higher intensities. And

so, the need to be physically active

changed. And if we think about the way

that our physiology evolved, our

physiology evolved in this context of

large levels of physical activity on a

consistent basis. And so, I like to

think of that as sort of the normal

condition for humans. And anything else,

so as we kind of progress into modern

times, and and many people have dropped

their activity,

that's actually the condition that is

quite different from the way that our

physiology functions best and and from

the way that our physiology evolved.

Does this mean that if I don't do

physical activity, my brain will shrink?

That's a good question. I mean, on a on

a broad public health scale, yes, you

know, low levels of physical activity or

inactivity is associated with poor brain

health, smaller volumes of key brain

structures, so smaller hippocampal

volumes, for example, and worse

cognition overall, and greater risk of

dementia and Alzheimer's disease. On a

personal level, it's hard to say

specifically, right? Because there's so

many factors that go into your risk of

of dealing with these conditions, but I

can say that the best way for any

individual to reduce their risk of

cognitive decline is to be physically

active. What exactly is going on in my

brain then when I'm physically active

that's causing my brain to be protected

insulated from things like Alzheimer's

and dementia and in some areas of the

brain to actually grow. What is what is

actually happening inside?

A lot of fun things. Um so I mean one of

the things that happens when we exercise

is we increase blood flow to the brain

and that helps bring nutrients and and

keep our neurons functioning properly.

But another thing that happens is that

your muscles actually generate proteins

called myokines and those travel to the

brain and they uh interact with neurons

in ways that upregulate neurotrophin. So

there's this great neurotrophin called

brain-derived neurotrophic factor BDNF

and BDNF acts kind of like a fertilizer

for brain cells or for new neurons. So

BDNF when it's up regulated with

exercise um helps both the birth of new

neurons and it helps them to survive and

integrate into the processes that

they're that they're meant to work for.

This is probably a stupid question but

I'm just wondering why the brain just

doesn't do that anyway. I know, right?

Wouldn't it be nice? Wouldn't it be nice

if it I didn't have to exercise for the

brain to restore itself in such a way

and to expand? It It would be nice in

some ways but that's just that's not

really the way that our physiology

works, right? So you know as I was kind

as I was saying if you think of the sort

of natural condition of humans as being

physically active because that's what we

had to do to find food and survive then

our physiology is adapted to that

condition and over the course of 2

million years we never had to adapt to

low levels of physical activity because

it just wasn't a part of being human and

so it's only been in the last you know

few hundred years that we've seen this

rapid decline in activity and that's

just not enough time to see that sort of

adaptation occur. What happened a couple

of hundred years ago that caused this

decline in physical activity? Was there

like a certain invention or something?

Was there a change in cultural

understanding?

I mean I think things start with the

Industrial Revolution.

Okay.

As we as we mechanize and we find ways

to um to reduce

um our the the need to uh be physically

active to gain access to food to survive

um and then as as we move on you know in

the last 50 60 70 years we start to see

a lot more office jobs, right? We start

to see changes in our work life that

reduce activity patterns throughout the

day. Cars, I guess.

Cars, so in terms of commuting, leisure

time. What do we What do most people do

during their leisure time? The couch is

really comfortable. Our screens are

really enticing TV screens but now phone

and computer and all these things and so

we ended we end up sitting a lot. Do you

have the stats on the increase in

sedentary behavior that is basically

people being still? It's hard in terms

of increase because we we haven't

measured time spent sitting for very

long. That's really been a pretty recent

part of research. Uh but we do know that

today people are sitting for on average

9 to 10 hours per day and that level of

sitting

um is also linked with really low levels

of then being physically active. So um

we can think about you know how many of

us are actually

active enough to meet the kinds of

guidelines that that are prescribed for

health um and we're talking about 25% of

US adults actually meeting those

guidelines and that number hasn't

changed in in 20 years or so even with

all the messaging physical activity is

good for you. You need to be more

active. You need to exercise.

You know people just don't do it. I

guess this the very heart of this is

this idea when we're talking about the

brain not just taking care of itself

without physical activity is this notion

that all parts of our body and all parts

of our being

are created in response pretty much or

at least develop in response to an

external stimuli of some sort. So like

me going to the gym the example I gave

earlier if I pick up the weight then the

muscle grows and whenever I try and

implement a very sudden behavioral

change like when I

suddenly started training football four

times a week my my muscles basically

exploded in my feet because they just

weren't strong enough to deal with that

demand and I guess the same applies to

the brain that if we don't use it

we we lose it basically. Yeah, I mean

our our bodies are uh fantastic at

tuning

what we put energy into to maintain to

the kinds of activities that we're that

we're engaged in, right? And so you know

I like to think of our bodies as great

energy minimizers in some ways that you

know if you're not using muscles those

muscles will get smaller because it

takes energy to maintain that tissue. If

you're not

you know creating the need for your

heart to pump blood across your body by

exercising you'll atrophy some of that

tissue. You'll you'll reduce blood

vessels. Your heart will become less

efficient because

you've signaled to your body that you

don't need that energy to put be put

into that tissue maintenance. The same

it seems holds true for the brain that

if you're not active um in some way then

you're kind of signaling that you don't

need some of that uh energy to be put

into that tissue.

Is all activity the same? So if I'm

doing strength training

is that as beneficial for my brain as

potentially going for a run outdoors?

That's a great question and um you know

we

there is not a ton of very clear work

that's compared directly different types

of activity in ways that we were where I

could tell you for sure this is the best

one, right? There are data that suggest

that resistance training is beneficial

to the brain. There's more work on

endurance activity and I actually think

that's probably because it's easier to

do rodent work on endurance activity

than resistance and so trying to

translate across those models is a

little bit easier. Both forms of

exercise have benefits. They may be

through different pathways. Um there may

be different biological mechanisms that

are underlying those benefits. I've kind

of seen some cool work coming out lately

that has tried to look at uh for example

different types of endurance exercise.

So there's a great study that came out.

Are you familiar with orienteering? It's

a sport where you're given like a map

and a compass and you have to uh find

your way across a route as fast as

possible. So it kind of mixes endurance

activity with spatial navigation and and

uh moving around your environment and

figuring out where you are. Typically

done outside, right?

Oh yeah, always done outside. Typically

done on natural like uh trails and

things but people do do it in cities as

well.

Okay. So like and this is over the miles

and courses.

this would be like a like a trail run

kind of or something like that. And

there was a great study that just came

out looking at um it was a randomized

control trial so they actually

randomized people into either an

orienteering group or a hiking group or

a control group and over a couple months

they found that the orienteering group

actually had uh better performance on uh

cognitive tests like memory tests and

executive function tests than even the

hiking group. Both of those groups did

better than the control group but there

was actually this extra boost if they if

for the people who were in the

orienteering group. So we're starting to

see that maybe some different activities

could potentially enhance the effects of

exercise on the brain. What's the

conclusion then? What does that study

hint at in terms of cuz hiking you're

out in nature you're navigating your way

up a hill or something. Orienteering

that it's it's almost like solving a

puzzle, right? Because you've got a map

and a compass. Yeah, I mean I think it

it fits into an evolutionary model at

least in my mind

um where the purpose of being physically

active is to move around a habitat to

find things. Find food, find water, find

firewood um and so physical activity in

a in this sort of ecologically relevant

world is a combination of cognitive

challenges and physical challenges. So I

think that when you combine them in the

way that perhaps orienteering does or

maybe some other sports you might

actually get a bigger boost for your

buck, a bigger bang for your buck um in

terms of the brain benefits. And that I

think is rooted in our evolutionary

history. Like I said I think that being

active in an evolutionary sense always

comes with sort of a cognitive

challenge. Nobody's ever just going out

for a workout. There's no reason to. If

you're not If you don't need to find

something you're going to relax and rest

cuz you're an energy minimizer, right?

Mhm. Don't spend that energy if you

don't have to.

Is there any animal studies that show

how um how doing challenging exercise so

cognitively challenging exercise so

exercise that involves problem solving

improves our neuroplasticity or

increases our the amount of brain cells

we have across our brain? Yes. Yeah,

there there have been and the

a great um

impetus for our work was some of the

work done in rodent studies

um by uh a professor named Gerd

Kempermann um and he and his group did

some work in in mouse models where they

combined uh access to running wheels

with a very enriched cage environment.

Um so they looked at they they did a

very careful study where they looked at

some mice who were just living in their

cage, you know normally a control group.

They looked at mice that were given

access to a running wheel. They looked

at mice that were given access to this

enriched environment this cognitively

challenging and things to play on and

then they looked at a combined group

where they combined the running wheel

with the enriched environment and they

found this effect where the combined

environment doubled the growth and

survival of new neurons compared to

either

wheel running alone or cage enrichment

alone. So, you got this really cool

additive effect

where you where you really enhance the

effects of either one of those behaviors

by combining them. If we can pull that

conclusion over to human life,

if we can if one assumes that the same

effect will be seen in humans, what does

that then tell us we should be doing if

we if our objective is to

live long, happy, healthy lives with

fantastic brains, what should we then be

doing exercise-wise? Well, I think

number one is just getting active,

right? So, I think, you know, to me the

number one recommendation is, you know,

to be physically active. And especially

for people who aren't that active right

now, um the best thing they can do is

get out and and start walking. Um but,

if we want to enhance the effects of

physical activity on the brain and build

on this animal work, we're starting to

see some good evidence that if you do

something similar, if you combine

physical activity with cognitive

challenges, you can boost the effects of

physical activity on um on the brain on

on especially cognitive uh performance.

And so, you know, most of the work has

been in controlled environments. So,

we've done a study where um we built a

uh a game that you can play while you're

on an exercise machine. Um so, you

combine exercise with challenging

activities, right? Um and we've shown

that you can actually get a bigger

benefit for cognition when you do that

than when you just exercise or you just

play a game. And so, we can, you know,

take that and perhaps translate that

into the real world and think about ways

that you can

um make your exercise more cognitively

challenging. So, can you go out and and

um challenge yourself spatially? Take

new routes, right? Often times,

especially runners or or walkers, they

just do the same route every time or the

same they have two or three routes that

they do every time depending on how long

they want to go. But, maybe we should be

challenging ourselves a little more,

right? Maybe we should take new routes

where you get a little lost and then

have to find your way back, right? I'm

someone that runs on the treadmill, but

Jack over there, he runs outdoors.

So, you're telling me, sort of top line,

that Jack is serving his brain more than

I am when I'm just on that same

treadmill every day in my hotel room

while I'm out here in New York, whereas

he's running around Central Park. It's

possible. So, I think there's there's a

couple things.

Um you know, running on a treadmill may

end up being a little more like running

on a running wheel for a mouse without

the extra enrichment. And yeah, running

outside may provide some of those better

benefits. We also know that running

outside actually has a lot more uh

benefits than just maybe cognition, but

also seems to boost mood a little bit

more than running or exercising in more

impoverished environments, you know, cog

you know, um Really? Uh yes. So, there's

like there's a research movement called

the green exercise movement that is uh

focused on

uh the impact of exercising in green

spaces versus um

more urban environments or or on indoors

on exercise equipment. And I don't want

to scare anybody. Like I said, exercise

is great. If if you if running on a

treadmill works for someone's lifestyle,

it is fantastic exercise, right?

know what I mean, I could go outside.

So, the only reason I'm not is because I

don't know the difference. Right. So,

you know, it's for for someone like me,

of course I could have gone outside this

morning instead of just um being on the

treadmill. But, I've I did I thought

they were the same. So, you're telling

me that there is potentially some

upside, according to research, in me

getting outside and running in both mood

and neuroplasticity makes me go, "Okay,

tomorrow I'll make a different

decision." Absolutely. I think that I

mean, to me that's the really surprising

outcome of a lot of this research is

that uh moving outside and especially

moving in green spaces, so moving in

um parks or near parks or uh moving on

trails, things like that, seems to uh

have bigger benefits, especially for

mood. We don't know yet about the

cognitive benefits. That's our

hypothesis, but certainly uh some of the

research out there suggests that for

mood and feelings of well-being, moving

your body in a green space provides a

little bit extra benefit than moving in

um in in like I said, in city streets or

in in indoors. One of the things I I

notice all the time is if I exercise

before I do this podcast, my brain just

seems to work. Yeah. Whereas if I get

out of bed and I don't exercise and then

I come and do this podcast, it's like

the words just don't go from my brain to

my mouth properly. Yeah. I mean, that's

why I got into this, right? Because I

started noticing the same thing. And I

started noticing how much better I felt

after I exercised. And, you know, on and

and to this day, right? I mean, my wife

knows when I didn't go for a run in the

morning, right? I'm not that pleasant of

a person to be around the rest of the

day. What is going on there? Do you Do

you know the sort of physiological

reason why it feels like if I exercise

in the morning before I have a two-hour

conversation, my brain and mouth seem to

be connected?

One of the things that I I think is

happening is that um you've activated uh

reward centers in your brain that have

increased your arousal, right? They've

you've activated these centers in your

brain um that are making you feel good.

And when we feel good, we feel more

confident. Um we're not as sort of stuck

in our heads. We're not as we're we're

more present. Um but, I think that is

rooted in the rewarding sensations of

exercise, right? It it makes us feel

better. And when you feel better, you

function better across all aspects of

your body or of of your life. Um and

those rewards are molecular rewards that

are that are popping up. It's There's

There's similarities with um with how

you people feel when they use certain

drugs. They're activating similar

receptors in your brain as when you're

using certain drugs, although to a much

lower extent. Um and it's really it's

making you, you know, sharper and and

making you more confident and making you

feel better. Is there a optimal time of

day to exercise? I know to your point um

about any exercise is better than no

exercise, but

is there an optimal time to exercise? I

mean, when do you exercise and why?

Well, I exercise first thing in the

morning. Why? Um because I will feel

better all day. Right? And so, I mean,

there's two reasons. I think one, if I

save exercise for later in the day,

there's a greater chance that things

will come up and I'll, you know, I'll

I'll find excuses not to. But, mainly

it's because first thing in the morning,

if I exercise, my whole day is better,

right? And so, that's the motivation to

get out of bed for me and and get out

the door is I literally think about how

I will feel if I don't do it. Um cuz

sometimes it's cold. Sometimes you don't

it's dark, you know, this time of year,

you don't want to do it. But, if I think

about how I'll feel the rest of the day,

um

that's a big motivator. And people might

hear this and they they might be

starting from zero, right? They might

not be exercising at all.

What would you say to those people? Not

to be intimidated by the advice out

there about how much you have to

exercise because it's actually

surprising how little you need to

exercise to gain benefits. Um so, if

you're starting from zero, the biggest

bang for your buck from a public health

standpoint are people who are starting

from almost zero and just starting to

exercise a little bit, right? Just

getting out the door and taking a

thousand steps, right? Something like

that. If you know, those those sorts of

uh

small amounts going from zero to two,

three, four thousand steps per day of

exercise, that's that's the biggest

public health benefit. Then you start to

see diminishing returns, right? So, if

you're if you're already exercising a

lot and you and you want to bump it up a

little higher, you know, the amount of

benefit you get is is smaller than going

from very little to to more. But, I

think that's the I mean, that's the

surprising thing for me is that, you

know, if you if you are not an

exerciser, getting four or five thousand

steps per day is going to give you a big

cardiovascular benefit and a big benefit

for your brain. You've studied some of

the tribes around the world. So, the

Hadza tribe, right? Is that

Correct. Yes.

What what work have you done with them

and when did that research begin? So, I

started working with uh the Hadza in

2009. That was my first time out there.

And we've been working with them and

interested in um what kinds of um health

impacts you see in a hun- in the context

of a hunting and gathering lifestyle.

And they live in what part of the world?

So, they live in northern Tanzania. Why

did you want to spend time with them?

So, the Hadza uh provide a window into

what a hunting and gathering lifestyle

looks like. And so, if if you work with

individuals who are still um pretty much

full-time hunting and gathering, um they

give you a view of how much physical

activity does it take to be a

hunter-gatherer, for example? And how

does that relate to biomarkers of

cardiovascular health or how does that

relate to their cognition? Um how does

this lifestyle impact the way that they

age? And the Hadza give us this really

important view of what that lifestyle's

like in terms of

behavior and activity and and um and

aging.

Is there a optimal amount of exercise

that's in line with our sort of

evolutionary past? We said, you know,

that we've evolved to be um active. Was

there Is there like an average amount? I

mean, do we see this in the Hadza

tribes? Do we have any clues from

history? Yeah, I mean, it so, we can

look at what living hunter-gatherers do,

and that provides us with kind of a clue

as to what that lifestyle um might

entail. And I like I do like to think

about things in terms of steps per day

often because that's an easy metric for

people to kind of understand and track

for themselves. There are more

complicated ways to to measure physical

activity, but steps is a good one, step

counts. And so, um the Hadza that we as

we've measured their step counts are

getting a lot. So, it's like, you know,

15 to 20,000 steps per day in that

range, which is quite a bit of of

movement. And that's not to say that

that is the optimal amount, um but

that's what we see in hunting and

gathering lifestyles. The benefits that

we get from a public health standpoint

start to occur at much smaller levels,

right? So, you know, 4 5 6,000 steps per

day you start to see some real benefits.

And as I said, you start to maybe see

diminishing returns as you get higher

and higher levels. So, what's what what

we see in the past or see in living

hunter-gatherers may be quite different

than what's necessarily you know,

optimal for our health in terms of you

know, where are we going to get the most

benefit and and where do we start to

trail off. With the Hadza, is that

across all age groups? Or is that Yeah,

I mean, there is a decline in physical

activity with age. That's clear. But um

but even older adults we've measured

physical activity in adults in their 70s

and even their early 80s and they're

still far exceeding what we do in in in

in the US or the UK or By factor of? A

lot of times the way that we measure

physical activity is in terms of how

much time they spend in moderate or

vigorous intensity activity.

Um so, these are kind of activities that

are that get your heart rate up up to

about 50 55% plus of your of your

maximum heart rate. And older adults are

still engaging in 60 70 80 minutes per

day of that kind of activity, whereas

say in the US you might see older adults

on average

engaging in two to four minutes per day

of that level of activity. Two to four

Yeah, so on average, right? For for

older adults. So, we just don't see as

much physical activity in in the US.

Like I said before, only 25% of adults

in the US meet physical activity

guidelines and physical activity

guidelines here are 150 minutes per week

of moderate to vigorous physical

activity. So, in the US 25% of adults

meet those guidelines. In the Hadza,

those that we have measured are meeting

weekly activity guidelines on average in

two days. So, they're getting

300 minutes of physical activity in a

couple days versus you know, adults in

the US who aren't coming close to that.

One of the biggest killers, I think

maybe the biggest killer of people in

the US and I believe in the UK as well,

is cardiovascular diseases.

Yeah. Is am I right in thinking that is

the single biggest That's the disease

you're most likely to die from? Yes, I

believe so. When we look at the Hadza,

how are they doing in terms of

cardiovascular illness? So, we don't see

a lot of evidence of disease risk. So,

we we have not yet measured

cardiovascular outcomes like we haven't

measured mortality for example from

cardiovascular disease, but we have

measured biomarkers. So, things like

cholesterol levels, triglyceride levels,

blood pressure. So, looked at whether

there's hypertension and we see very

little evidence of cardiovascular

disease

in this group. Others other researchers

have looked at other

Um there's a long-term study of a group

in South America called the Tsimane

that have been studied in a lot of

detail and there they found almost no

evidence of cardiovascular disease and

they've been able to look in a much more

detailed way at outcomes like you know,

death from cardiovascular disease and

they see almost no evidence of

high levels of cardiovascular disease.

Diabetes? Very little evidence of

diabetes, very little evidence of

dementia. I mean, these diseases that we

look at as inevitable parts of aging,

they're just not, right? They are not

inevitable. A lot of them are a product

of our lifestyle. And you know, I'm I'm

most familiar with dementia and

something like 40% of risk of dementia

is preventable. It's due to lifestyle.

Right? We have the ability to modify our

risk in really big ways by altering the

way we live. What else has inspired you

or caused you to implement behavioral

changes into your life, new habits based

on

your work researching the Hadza tribe?

Is there anything at all that has

either changed your mind or modified how

you live your life? Yeah, I mean, I

think a couple of things. Number one,

physical activity is is sort of the

cornerstone of my life. That's sort of

that is that is

that's been driven by my personal sort

of

enjoyment of it, but also from a

research standpoint that's been really

motivating to maintain an active

lifestyle across these years. But more

recently I've been really interested in

sitting,

which is you know, in some ways

it's it's not really the opposite of

being physically active, but it's it's

another behavior that we engage in

actually for much more time per day than

than anybody's physically active. And

we've done a lot of work on resting

behaviors in the Hadza and that's been

an area that I've sort of tried to pull

into my life as well as

trying to understand you know, how

sitting can impact our lives and then

how our evolutionary biology may

may be tweaked by by this behavior. And

so, I've tried to implement some things

like trying not to sit too long, trying

to break up my sitting,

finding ways to

to not be stuck on in a chair all day.

And a lot of that's driven by by my

research. What's the what's the issue

with sitting? So, sitting is sitting's a

beautiful thing, right? I mean, we're

doing it right now. It's really

comfortable.

And the reason it's comfortable is

because we've basically taken all of the

load off of our lower body. So, we're

we're supporting ourselves in these

chairs, right? You got to move around

Now that you mention it, I'm not You

know, when I give talks about sitting

all of a sudden I start seeing people

fidgeting, right? Some people get up and

and stand up in the back. So, you know,

you take the load off of your lower legs

and your muscles don't have to work and

you know, not surprisingly that's super

comfortable. We're not working hard.

But at the same time what's happening is

the our muscles not being active means

that what we normally do to fuel muscle

activity, which is you know, we break up

triglycerides in our bloodstream and

that's you know, that's those are broken

up into fatty acids that fuel muscle

activity, that's not happening. And so,

those those fuels now build up in our in

our blood vessels and that's associated

with cardiovascular disease. So, sitting

for long periods of time is associated

with some negative health outcomes. And

one of the things that we've learned

from working with the Hadza is that you

know,

people rest a lot. Like the Hadza, they

sit for as or or rest and sit for as

long as we do, which was actually super

surprising to us. We thought that

wouldn't be the case. We thought they

were going to be active you know, all

the time and there would be much less

sitting, but when we finally actually

measured it with accelerometers,

they're resting for the same amount of

time that we are.

But they're not sitting in chairs.

They're resting in postures that require

a little muscle activity. So, they're

squatting or they're they're kneeling or

they're sitting on the ground in ways

that you know, you have to kind of keep

shifting your body around.

And it's possible that just that kind of

low level of muscle activity

is is how our bodies are well adapted to

rest. And what's weird is the invention

of chairs. What's weird is the invention

of these objects that completely

eliminate the need for our lower bodies

to use muscle activity. A A chair is a

fairly new invention. When when did

chairs come into the picture? The first

chairs that we know about from the

archaeological record are about 5,000

years old. Um but you know, the

ubiquitous use of chairs is is probably

even more recent than that, right?

Chairs are chairs are these weird

objects that they're not only you know,

ergonomic and and and made for you know,

our comfort, but they also over history

have had implications for economic

status and power and you know, taking a

seat at the table and a throne in in you

know, in in terms of political power.

Where you sit is always been important

from a political and and economic and

social standpoint. So, chairs have have

sort of taken on a big part of our

lives. And if you you know, if you walk

into someone's house, you know,

generally the first thing that you're

seeing is their seating environment,

right? Chairs and couches and

and and places to sit are part of the

way we design our world.

We don't think about them that often,

but we use them more than almost any

other object in our lives. It's kind of

like we assume they've just always been

a thing. It's probably most things in

our life we assume that this is just the

way it's always been and this is

therefore normal and acceptable.

But it must be pretty illuminating to go

and see these tribes who

they must think we're crazy. They must

think we're so strange by the things

that we do. I mean, they do, but at the

same time, you know, when we work in in

Hadza land, we bring chairs cuz they're

comfortable. And you know, the the first

thing that happens when we're out there

is you know, this crazy game of musical

chairs that if one of us gets up, you

know, someone comes over and sits in our

chair. And why is that? Cuz they're

super comfortable. Um and so, I don't

think they they necessarily think we're

crazy. I think they

you know, they enjoy sitting in the

chairs.

Um they just don't have them. Be careful

not to leave any of them there cuz

Well, that's what you know, that's what

happens is you know, we'll go out for

the day and and go you know, go

you know, foraging with people and and

come back and you know, you can't find

You want to sit down and you can't find

a chair cuz everyone's sitting in your

chair, but that's totally fine. They

they deserve to rest just as much or

more than than anybody else. What's the

practical advice do you think there for

for employers, for people that work at

home, for people that sit in chairs

often because we

people can't just we can't just do this

podcast squatting. Right? Well, we

could, but you know what I'm saying?

challenging. It'd be very very

challenging. Is there some kind of

middle ground that is accessible and

realistic for us? Yeah, I think the I

think the best thing people can do is

just try not to sit for prolonged

periods of time. I mean, there's no way

to eliminate sitting and I don't think

that standing all day is is necessarily

the answer. I don't think that that's

necessarily a a

benefit full-time. I think breaking up

sitting into smaller periods is probably

the best thing we can do.

Um so, you know, one of the pieces of

advice is is actually that I always tell

people is, you know, just drink more

water so you got to get up and pee more.

Um that is That's an easy way to to kind

of force yourself not to sit for 2 hours

at a time. But, you know, having those

kinds of reminders that you should get

up, move around.

Um there's been this popular notion of

taking exercise snack break. So, you

know, every 30 minutes, every 45

minutes, get up and walk up a staircase

or do some push-ups or something just to

get your body moving, get your muscles

working, do some squats.

Um and so, that can be, you know, really

beneficial.

Some people hear that and go, "Hippa, if

just doing just getting up and doing a

2-minute walk, how's that going to help

in the grand scheme of things?" There's

really good evidence. So, okay, couple

things. Um

from an epidemiological standpoint,

there's been this really great work

coming out on

um something that's called vigorous

intermittent physical activity.

Um so, this is

um

activity that's not purposeful. It's

short duration, but it's vigorous. So,

going up the stairs or walking really

briskly for like a minute or two.

That in the long run, people that do

that often have a lower risk of

mortality and a lower risk of

cardiovascular disease, regardless of

purposeful physical activity, right? So,

you can actually get big benefits by

just doing these short bursts of

activity. Walking to get your lunch or

at a vigorous pace.

At a vigorous pace, okay.

Right? Yeah, I mean, walking to get your

lunch is great, but you get a little bit

more benefit from doing it at a vigorous

pace. So, you know, if you're walking

and you can't sing at the same time or

you can't talk at the same time, that's

that's now you're getting into kind of a

vigorous intensity. Um and there's also

been randomized controlled trials where

people have actually in the lab had

people sit for, you know, 8 hours, not

do anything. And then they've taken

those same people on another day and had

them sit but break it up into, you know,

20 minutes, break it up and walk on a

treadmill for 2 minutes, something like

that. And those studies have shown

changes in cardio-metabolic markers. So,

they've shown shown changes in um

insulin levels and changes in

um in triglyceride levels and and

cardiovascular disease biomarkers just

from breaking up your sitting in into

into shorter periods. So, you really can

have a a profound effect, I think, on

your health um by implementing some of

these small changes.

Is there, you know, a type of exercise I

have we touched on this a little bit

earlier on, but I'm really trying to

make a case to myself that I should be

doing more aerobic exercise

than I typically do a little bit of

aerobic exercise um unless I'm training

for something in particular and a lot of

sort of resistance training. Is there

any case that I should be doing more

aerobic exercise or resistance training

if my goal is to

improve my brain, my memory, my

cognition? I think I mean, I think both

are important.

Mhm. Um

from from my perspective, aerobic

activity, you know, we're we're thinking

about this from an evolutionary

standpoint, right? We've been talking

about this idea of can we boost the

effects of exercise by adding cognitive

challenges, right? And so, from my

perspective, aerobic activity is

probably the place where you can do that

um in the easiest way. Um so, by moving

yourself outside a new environment, um

by adding in some some spatial

navigation challenges to a workout, you

might be able to do that a little easier

than when than when you're lifting

weights. You know, this whole brain

training industry that emerged I think

it emerged like 10 years ago and there

became all of these apps that were kind

of like puzzles and stuff and they

claimed that if you use these apps and

do this brain training stuff, then it

will

um make your memory better, your IQ

higher, all of these things. Is there

any merit to these brain training games?

There does appear to be some. Um so,

there do appear to be some training

games that that do improve aspects of um

of cognition. Uh you know, it's been a

it's been a tough industry because not

all of the studies are super high

quality um and and some of the claims

can be a little bit further ahead of

maybe where the science is. So, are the

effects that big? Like if you do it, you

know, every day and you invest all this

time, are you going to get the biggest

effect? Um but there does appear to be

some benefit. You know, if I were in a

perfect world, would I be doing

everything I could

um to stave off the potential for

developing dementia? Yes. And so, if

there's a little bit of evidence that

that could be helpful, I would I would

definitely jump in and do it. Just

learning generally. Yeah, learning So,

learning

education,

um keeping yourself cognitively

challenged throughout your lifespan is

clearly um a way to keep staving off

cognitive decline. Is there research to

support the idea that learning or

reading or some kind of education?

Yes, for sure. For sure. And and, you

know, education is a difficult one

because education is wrapped up in a lot

of other things, right? So, education is

wrapped up in um your parents and

socioeconomic class. And so, when we

study education from an epidemiological

standpoint, it's really hard to deal

with um the kinds of other variables

that could confound those relationships.

But certainly lifelong learning seems to

be associated with better reserve. So,

one of the things that we think about in

terms of cognitive aging is how much

reserve do you build up over the course

of your lifespan so that as we undergo

some atrophy and decline, which isn't

which is kind of inevitable, um have you

built up enough reserve so that that

decline doesn't impact your daily life,

right? You you have enough of this

built-up tissue and built-up reserve and

built-up connections

um that even if you undergo some decline

or in in tissue, it doesn't impact you.

Reserve being kind of like pathways. Is

that what Reserve could be pathways.

Right. It could be volume. Volume, okay.

So, it could be a bigger hippocampus or

it could be the connections between your

hippocampus and and other parts of the

brain. And both of those are are

important and you can build those up

across your lifespan with physical

activity, with um

cognitive engagement, um things like

that. And with avoiding some of the sort

of negative health behavior like smoking

or excessive alcohol use. Does excessive

alcohol use mean drinking shrink the

brain? They do. They are They are risk

factors in cognitive decline and the

development of dementia and Alzheimer's

disease. How much alcohol?

We know that excessive, like, you know,

excessive consumption over the sort of

one drink per day or two drinks per day

for a man, one drink per day for a

woman,

um

that level of alcohol consumption is

associated with negative health outcomes

including

risk of dementia and Alzheimer's

disease.

Is So, sleep is the other one that's a

big a big factor in cognitive decline,

right?

And sleep is I mean, a lot of things

happen during sleep um that are really

important. One of the things that

happens during sleep, we think, is that

um it's a time where your brain is

clearing these plaques that can build up

that are associated with um

neurodegenerative disease. And so, if

that's the case and there's been some

evidence that suggests that that sleep

is when some of that clearance is

happening, then poor sleep quality

just doesn't allow that function to

occur, allows those uh plaques to build

up. Sleep is weird in some ways because

it's not always more is better.

So, uh it follows a U-shaped curve in

terms of risk of developing dementia,

for example, where less sleep

and lots of sleep are both associated

with higher risk. And there's like a

sweet spot, right? There's a sweet spot

of, you know, call it 7 and 9 hours a

night, something like that. Um that

that's that is where your lowest risk is

going to be. So, you can oversleep. You

can. Here's the the the the caveat to

that is what's going on with

oversleepers that you're not able to

suss out in your analysis. So, a lot of

times people oversleep because they're

depressed. And we know depression is

linked with these neurodegenerative

diseases. And so, it's it's possible

that it's those it's not the actual

sleep itself, but it's what's linked

with too much sleep.

Like inactivity. They might not be

exercising as much as I am.

Yeah, what are you displacing? So,

another Yeah, that's a great point.

Another thing that we can look at is,

you know, you have 24 hours in a day,

right? And so, if you sit for an extra

hour, that's going to come at the

expense of something else. If you sleep

for an extra hour, yeah, or exercise or

light physical activity, just housework

or something.

Um so, you can't

the day is not infinite. So, anything

that you choose to do is displacing

something else. What about having

friends? Yeah, having a partner, you

know, does that is that going to

increase my chances of having a great

cognitive function and a big brain?

Well, it depends on how good your

relationship is.

So, I mean, just having a partner

sometimes, you know, if it's if it's

there are ways that that can be

associated with negative outcomes if if

your relationship is Tell me about it.

is challenging, right? Um but, you know,

so I think of healthy aging as linked to

really three main behaviors.

Diet, physical activity, and social

connections. Okay? Social connections

are key. And so, you know, we're hearing

now there's a kind of a buzz where the

epidemic of loneliness, especially

coming out of the pandemic years, that

is really um it's kind of frightening

because people have gotten more used to

sort of living alone or being alone. Um

and those social connections are a key

aspect of maintaining a healthy brain

when we age. We know that. Um and

How do we know? Well, mainly from

epidemiology. There's two ways to two

ways to analyze these these these

questions. There are are randomized

control trials and sort of observational

trials.

It's really hard to do randomized

control trials on loneliness and and

look at long-term outcomes. So, we look

at observational data and people who

have stronger social connections, who

have um it's not necessarily more, but

it's it's

higher quality social connections. So,

you know, if you ask them if they have

people they can confide in, they'll say

yes. Um those people tend to have better

brain outcomes than people who who don't

have those connections. And if you think

about it, again, I I I don't want to

make a a sort of

an easy evolutionary argument where we

just say, "This is how we evolved, so

this is how we live should live now."

But I mean, if you think about our

evolutionary history, for the most part,

we lived in a in a time where social

connections were imperative to survival.

Right? I mean, if you are living in a in

a hunting and gathering lifestyle, you

know, you need those social connections.

You can't guarantee that you will find

food every day. So, you need to have

connections with other people who you

trust and they trust, who you're willing

to share with. Right? And so, those

social connections become

um become inextricably linked to your

health. Does pollution have an impact on

our cognitive performance? Yeah, that's

been so that's been a surprising and

really kind of sad result of a lot of

research lately is that air pollution um

has real negative impacts on brain

aging. Um and we've seen that in acute

studies where people have looked at um

the effects of you know, what's going on

in your in your peripheral blood when

you commute in traffic, right? When you

ride your bike in traffic. Um but also

from an epidemiological standpoint,

people who are living in areas with

higher air pollution have a higher risk

of developing Alzheimer's disease and

other dementias. Um one of the things

that we've done some work on, we were

really interested in whether physical

activity either could um you know,

diminish those impacts of air pollution

on the brain, but also we were thinking,

well, when you're active, you're

breathing more, right? Your your your

your respiration increases, so you're

breathing in more uh pollution, more

particles. So, could that actually, you

know, have an impact on the benefits of

activity on your brain? And we found we

we've looked at a look at this in a

couple ways and both for some brain

structural outcomes and for risk of

dementia, exercising in or being

physically active in in an area with

even moderate levels of air pollution

diminishes the benefits of physical

activity on the brain.

Which is a real bummer. Especially for

me, I live in Los Angeles, which is a

very uh it's an area with a lot of air

pollution. And um and so, being

physically active in that environment

when there's a lot of pollution in the

air, um it doesn't it doesn't make your

health outcome worse, but it diminishes

the benefits of physical activity. So,

if you go for a a run in the middle of

London, for example, or in the middle of

New York City, the

cognitive benefits are diminished.

That's what we're seeing in the data.

We're seeing and in fact, the study that

we did was was uh from data uh based in

the UK where, you know, we're not seeing

the kinds of levels of pollution that we

see in some other cities around the

world where it's really drastic or even

in Los Angeles where it's much higher

levels of pollution than we'd see in say

London. But even in those levels with

more moderate levels of air pollution,

um people who are active in in higher

levels of air pollution don't show the

same brain benefits as people who are

active in areas with lower

pollution.

I had my brain scanned uh

what, 2 months ago now? And it was okay.

Okay. It wasn't

amazing. It wasn't

okay? I mean, he just told me there was

room for improvement in terms of like

some things he saw in my brain. He also

diagnosed me with ADHD following that

and a few other questionnaires and and

things. One of the things in my sort of

prescription

that he asked me to do more of was

racket sports.

Interesting. Okay. He said, "If you do

this list of things that he's asked me

to do, things like hyperbaric chambers

and blah blah blah blah blah blah and

racket sports, um

we'll see an increase in certain parts

of your brain."

Now, that somewhat ties into what you're

saying with doing this physical

activity, but pairing it with some kind

of cognitive challenge. Racket sports

seems like a prime example.

it's funny. It it is the number one

question I get after I give a talk is

about tennis. And I think I probably you

know, I give talks a lot in in you know,

to communities with you know, more

sometimes more affluent older adults who

probably play a lot of tennis. And but

it is, you know, it's an activity that

people play can play later in life, you

know, um and um and it does involve a

lot of strategic thinking, it involves a

lot of fast reactions, and it involves

aerobic activity.

Um and so, it is it's a great contender.

And you're doing it with

doing it with someone. It's social.

Um often times, especially uh when you

get a little older, you play doubles, um

so you don't have to run the court as

much. What are the other questions

people after hearing you speak? What are

the other questions that people often

are most curious about? How much

activity? That's the big one, right? How

much do I have to do? Yeah.

Do I have to do?

Right. And that's the way people think

about it. Yeah. And it you know, I think

have to do. Yeah, and it it

it's it sort of does bum me out to frame

it that way because

um because I think of physical activity

as as something that as as we were just

talking about, it improves your whole

day. Um it's something that many of us

want to do because of that, right? And

so, I think, you know, first the first

thing I always tell people is find the

activity you want to do.

Because that's the one you'll keep

doing. And so, don't look for the

perfect, right? If running on a

treadmill makes you crazy and you don't

want to do it, then you won't keep it

up. Um if playing tennis does it for

you, maybe it's not the best if we if we

can even figure out what that means, but

you're going to do it for the rest of

your life, then by all means, that's the

one to do. And so, I think that is the

first thing that everyone should be

thinking about is, you know, what do you

what do you what makes you excited to

get out the door and do? Um

and don't worry about what's best.

What is the research that you've done

that you're most

proud of or that's surprised surprised

you the most?

Cuz you know, I've I've been looking

through your work and found different

things that I found interesting, but um

I must have missed something that you

find really fascinating. Well, one of

the things that I found really

surprising was actually it was it's now

been a while. It's been like

over a over a decade ago, I did some

work on um the endocannabinoid system.

Um and the endocannabinoid system is our

body's uh sort of natural form of

marijuana. You know, we produce these uh

chemicals that activate brain receptors

the same way that the active ingredient

in marijuana um activates. And so, um it

turns out that exercise upregulates this

same system. Um these endocannabinoids

and that may be why at least partially

why exercise makes people feel good. Um

and one of the studies that we did, like

I said, about 10-11 years ago now, uh

was we found that the same thing that we

get from exercise in terms of

endocannabinoid signaling, dogs also get

that. And I'm I'm a dog lover and and I

know my dog loves to exercise and she's,

you know, bummed out if she can't get

her her her walk and run in for the day.

And I think there's something similar

are going on. It's these similar

rewarding mechanisms that make them feel

good that that makes us feel good. So,

that was one um one really fun and and

interesting kind of finding that I think

has some implications, right? It's it's

if if if we can find those activities

that generate those rewards, we're going

to want to do that more often. And it

also provides a sort of physiological

explanation as to why some people who

don't exercise or unable to exercise can

often have depressive symptoms. Agree. I

totally agree. Yeah, and I think these

biological mechanisms that can that can

make you feel better when you exercise,

they don't always kick in right away,

right? And so, I also think they can be

a that can be a little bit of a barrier

to someone who's not active that, you

know, if you just get up and start

exercising, you know, maybe it takes a

little bit of time for these things to

kick in. You have to be able to stay

within a certain intensity level and

maybe if you're not very fit, you kind

of overshoot that and you you end up

going to too intense and you don't get

those same sort of mild benefits that

just make you feel good all day, right?

I think one of the things that people

need to kind of keep in mind is is maybe

try to stick with it long enough to get

a little bit of fitness so you can reap

those rewards. They'll come. You just

need to just give it some time, right?

Have you got any

hypotheses that you're working on at the

moment

that you haven't been able to prove out

yet, but you know, as someone that's a

researcher and that's insanely curious,

there must be things in your mind that

you're thinking, "I'd love to do a study

on that to figure out if that's

true?" Yeah, I mean, so a couple things.

I mean, one, we are not done with the

combining cognitive challenges with

physical activity. I think that is a

really um

a really exciting area and it's it's

early on. So, I think the the work that

we've done and others have done is in

its infancy in how we can boost the the

the brain benefits of exercise. And

that's sort of that's going to be a big

part of our work going forward is what

can we do to really um make exercise a

little more cognitively challenging and

get those benefits. Um the area that I'm

that I'm really interested in now um is

the effects of sitting on the brain.

And um what are the mechanisms that link

too much time spent sitting with brain

health? And how can we kind of manage

that a little bit better? You know, when

we think about

exercise participation, and I've been

saying, you know, 25% of adults uh

engage in in

uh the guidelines for physical activity

levels in the US. That number hasn't

changed over the last, you know, couple

decades. All the messaging, I mean, you

know, would you could you ever meet

someone who doesn't know that physical

activity is important to do? But still

75% of people don't exercise. And so I

don't know what it'll take to to change

that number.

But I think maybe we can look at other

behaviors that we can change. And

sitting is something that everyone does.

And so that I think is a really nice

place to focus to move the needle a

little bit. So can we get people to sit

less?

What are the kinds of interventions we

can implement that can get people to to

reduce their time spent sitting and will

that pay off in terms of brain health?

And I think that's it's a big question.

We know that time spent sitting is

associated with risk of dementia. We

just we just did a big study looking at,

you know, if you if you sit for 10 hours

a day

compared to

9 hours a day, it's about a 10%

increased risk of dementia. If you sit

for 12 hours a day, it's about a 60%

increased risk of dementia compared to

sitting for 9 9 and 1/2.

60%

60% versus 9 hours a day. Right. So just

a couple more hours, right? It's it's a

non-linear relationship. So once you get

past about 9 9 and 1/2 hours a day, your

risk start going up in in a non-linear

exponential way. And so

can we alter that? Can we I mean it

doesn't it doesn't take a lot

necessarily to go from 12 to 8 hours a

day.

So

maybe that's easier than getting people

out the door. Maybe we can find some

find some intervention. So that's what

I'm really excited about is, you know,

some of some low-cost ideas, some

low-investment ideas for people

that could maybe have a big impact on

the way they age. I'm thinking about all

kinds of chairs that vibrate and

give you an electric shock. I'm thinking

of how we can implement that into Whoop,

which is a company I've I'm involved in.

Totally. Yeah, I mean reminders are one

way, right? I mean I think tracking your

behavior. I mean there are it's not

going to work for everybody, but

certainly tracking your time spent

sitting for a couple weeks might

actually give you a little bit of

motivation once you realize just how

much time you spend on these chairs.

What is brain foods? Is is there such

thing as a brain food? I I think I much

of the reason I take omega is because

people tell me it's good for your brain.

Yeah. I don't you know, I don't think

there's a magic pill.

You know, I think the best evidence that

we have right now is

is more plant-based, less meat-based,

especially less processed meat. More

plant-based.

More plant-based foods and and less

meat. Less meat.

Yeah. Here's where the difficulty lies

in all of this research. To study brain

health, you need to observe people over

long periods of time. And so you can't

implement

a 10-year diet intervention. Just nobody

will follow it. So all of the research

that's really strong in this area is

asking people to report what they eat

and then tracking what happens to them

over time. So it's

it's difficult work, but the best

evidence is that aspects of the

Mediterranean diet seem to be linked

with better brain outcomes. So more

plant-based, more

more legumes, more whole grains, less

processed food, less meat, less sugar.

These are you know

these are the obvious dietary

interventions, right? And I think

they're they're obvious for a reason

because they seem to be so good for so

much of our bodies and you know, so much

of our cardiovascular metabolic health

and our brain health. If there was one

fundamental misunderstanding that most

people have

that your work and your experience has

rebuttled, I guess.

What is that fundamental human

misunderstanding about the nature of our

bodies and how we're supposed to be

living to be optimal? I think

I think the most dangerous

misunderstanding is how much exercise it

takes to get benefits. Right. And I

think that's because that acts as a

barrier to people. And what we've seen

from the epidemiological work is that,

you know, the the

there are minimal amounts of activity

that provide big benefits.

More is generally better, but you can

get huge benefits just by moving your

body a little bit every day. And so I

think that's, you know

as I said, it's a dangerous

misconception because it's a barrier.

When someone thinks when someone doesn't

exercise at all and thinks I need to get

12,000 steps per day and I'm tracking it

and I'm getting 3,000, that's a pretty

big gap and that's one that maybe

you don't think you can fill. But if

you're getting 3,000 and you think if I

get to 5,000, I'm going to get a big

benefit

that's motivating, right?

Is it so true that sometimes going from

zero to one feels so

inconsequential

and somewhat embarrassing

that we just don't do it because we I

think many people think of zero to one

is like zero to a

five-day-a-week gym attendance record.

Right. Which is just like climbing Mount

Everest in your mind.

It's just so far away that there's going

to be so much psychological discomfort.

It's going to result in procrastination.

You're going to do something else and

you're going to avoid it. But if we

reframe that to zero to one being

walking for your lunch. Yeah. And that

as the starting point and then one to

two being as you said going from 1,000

steps to maybe 2,000 steps. Feels like

something everyone can do, but we just

don't think it's important. We think

it's totally inconsequential to

go for a walk as opposed to

um

you know, just sitting down and ordering

our food on an app. Yeah. Something that

I I think about a lot cuz even someone

like me that I I go to the gym, you

know,

as frequently as I possibly can.

However, there are some days like today

where I'm extremely busy where I might

have said I was going to go to the gym

late at night and I either think to

myself that

there's no middle ground. I think that's

either going to the gym and working

really hard or [ __ ] it. Yeah, yeah.

There's great middle ground now. Yeah.

You can run up the stairs on your way to

bed, right? You know, I mean you you or

you you know, you can do these exercise

snacks. But I like to think of the the

things that you're talking about, you

know, walk to lunch instead of ordering

in. Mhm. You think that's not important

maybe. It's life-changing for some

people. It will literally change your

life if if you are doing very little and

you take that first step.

You know, it can change everything about

your, you know your future in some ways

because it builds the foundation for oh,

that feels good. Maybe I'll try a little

bit more, right? Maybe I'll try a little

bit more. You know, we're talking

earlier you were saying, you know, you

implement a new exercise regimen and you

jump in with everything and then you end

up, you know, getting a Achilles tendon

injury or something like that. You know,

that's especially true of people who

don't exercise at all. And so, you know,

the best thing to do is to start slowly

and really start reaping those rewards

because that's the motivator. And so

yeah, I mean I think if you are

exercising a lot, you know, day that

gets away from you and you can't make it

to the gym,

I mean getting a little bit of vigorous

activity, going for a really brisk walk,

going up the stairs, doing some push up

I mean anything is going to give you a

little bit of benefit.

You know, these are really easy things

that we can implement into our lives.

Quick one from one of our sponsors. A

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Does Alzheimer's exist on a spectrum,

per se? And is is what one end of that

spectrum sort of just general cognitive

decline and memory reduction? Cuz I

sometimes wonder obviously my job here

is to I interview very intelligent

people and those people come in all

shapes, sizes and ages.

And I obviously, as an observer

notice how some of the older people that

I meet

are incredibly

sharp.

You know, arguably significantly sharper

than I am. And I'm, you know

in some cases

30% 40% of their age 40% of their age

and they're just unbelievably sharp. And

then we've also all had experiences

maybe with an older relative or you

know, someone slightly older where you

can see that

that their memory recall or their sort

of it's almost sometimes you experience

as their self-awareness has started to

wane. They might tell you

a short story in 1 hour, if you know

what I'm saying. They might they just

it's almost like the self-awareness of

what they're saying and how they're

saying it and their ability to

articulate themselves is some somewhat

slipped away. And I wonder if that

exists on the scale of dementia or

whether that's just general atrophy as

you call it of the brain.

Right. And I don't I really really want

to be someone, as I'm sure we all do

that has my brain works until the day

that I die. Yeah. You know. Yeah. We all

want that. Yeah, we all want that. Of

course. And I that's why I wonder if

it's the spectrum or is it is a

spectrum.

Yeah, I mean so there's sort of

a normal amount of cognitive change that

happens with aging in in most people