180. The Truth About Cortisol, Insulin & Overtraining | Shawn Arent, PhD, CSCS

Show Notes

We are back with a powerhouse guest, Dr. Shawn Arent, for part 1 of a series on hormone optimization. From cortisol misconceptions to insulin fearmongering, they cut through the noise with science-backed insight into performance, recovery, and stress physiology. You’ll rethink everything you’ve seen on social media about hormones.

TIMESTAMPS

00:00 Introduction to Medicine Redefined

00:36 Welcoming Dr. Sean Arent

02:11 The Importance of Cortisol

02:49 Understanding Cortisol's Role in Performance

04:59 Chronic Cortisol and Overtraining

13:51 Monitoring Stress and Performance

22:30 The Role of Nutrition in Cortisol Management

33:31 Insulin: The Anabolic Hormone

39:27 Exercise and Insulin Sensitivity

40:43 Impact of Stress and Sleep on Glucose Levels

43:02 Continuous Glucose Monitors: Pros and Cons

47:42 Athlete Nutrition and Performance

55:52 Hormonal Responses to Training

01:07:18 Sex Hormones and Athletic Performance

01:17:37 Conclusion and Future Topics

SOURCES

00:00:22 | Cortisol deficiency (Addison’s disease) is life-threatening

00:04:42 | Cortisol peaks in early morning (chronobiology) 

00:05:25 | Acute sleep deprivation significantly increases cortisol 

00:05:42 | One week of 5h/night sleep restriction lowers testosterone by \~10–15% 

00:22:11 | Cortisol stimulates gluconeogenesis (maintains blood glucose upon waking) 

00:27:38 | No single reliable biomarker for overtraining syndrome 

00:27:38 | Overtrained athletes show blunted HR, blood lactate and cortisol responses 

00:29:00 | Prolactin rises in response to stress/exercise 

00:30:00 | Dietary fat guidelines: 20–35% of calories from fat 

00:33:30 | Insulin is an anabolic hormone promoting nutrient storage 

00:33:30 | Low-fat (∼20% fat) diets reduce testosterone 10–15% vs high-fat diets 

00:39:26 | Regular exercise improves insulin sensitivity 

00:39:26 | ~38% (~98M) of U.S. adults have prediabetes 

00:40:29 | Shorter sleep duration impairs insulin sensitivity 

00:01:02:57 | Exercise above the lactate threshold elicits maximal GH release

01:04:42 | Resting lactate \~1–2 mmol/L; intense exercise >20 mmol/L 

01:08:53 | Higher testosterone levels correlate with greater lean mass in men 

01:11:51 | Winners in competition show post-event testosterone spikes 

01:12:29 | Female athlete amenorrhea leads to low bone density and stress fractures

01:12:29 | Amenorrheic female athletes have lower IGF-1 (growth factor) 

01:08:53 | Testosterone even within normal range affects strength/mass

What is Medicine Redefined?

Medicine Redefined challenges outdated conventions by elevating conversations around what health truly means. Hosts Dr. Darsh Shah and Dr. Altamash Raja spotlight clinicians, scientists, thought leaders, and reformers who are reshaping how we think about physical, mental, metabolic, and systemic health. While the healthcare system focuses on treating disease, our guests focus on optimizing human potential. From sleep and nutrition to stress resilience and lifestyle medicine, discover how forward-thinking practitioners are putting the health back in healthcare.

Welcome to Medicine Redefined, a
podcast focusing on helping you

reclaim ownership of your
health.

I'm Doctor Darsha.
And I'm Doctor Ultima Shraja,

we're your hosts here to
challenge conventional practices

and uncover the stories behind
pioneers shaping the future of

medicine.
Our conversations not only focus

on the individual level to
dissect common practices for

health optimization, but also.
Zoom out to enhance systemic

change.
Join us as we look to break the

status quo, move the needle
forward and put the help back in

healthcare.
Social media is flooded with

hormone optimization advice that
can actually sabotage your

performance.
Arcus today is uniquely

qualified to separate fact from
fiction.

He's also repeat guest that long
time listeners will recognize,

and he is none other than Doctor
Sean Arndt.

Dr. Arndt is a leader in the
world of human performance and

sports science.
He's a professor and the chair

of the Department of Exercise
Science in the Arnold School of

Public Health at the University
of South Carolina.

He also directs the USC Sports
Science lab.

Previously, he was professor and
Rutgers University, where he

directed the Center for Health
and Human Performance.

And this is where we cross
paths, and he has been a mentor

to me since.
Doctor Arn's research focuses on

the relationship between
training, nutrition, and stress

and their implications for
health, performance and

recovery.
He is a certified for the

Conditioning Specialist with
distinction with the NSCA and a

past President of the
International Society of Sports

Nutrition.
His work has been recognized

with numerous honors, including
the NSC as 2017 Outstanding

Sports Scientist of the Year and
the Lifetime Service Recognition

by the US Army.
He has received grant funding

from the DODNIH and the Robert
Wood Johnson Foundation and has

worked with U.S.
Special Operations Command as

well as teams and athletes in
the NHLMLBNBA&NFLI brought Sean

on to cut through the noise in
our own hormone optimization, a

topic where misinformation runs
rampant.

About halfway through our
conversation, I realized there's

no way to cover this
comprehensively in one episode,

so we decided to make this part
one of two.

Here we'll discuss cortisol and
it's misconceptions and

performance.
Sean clarifies the essential

role of cortisol in mobilizing
resources during exercise and

explains why acute elevation
differs fundamentally from

chronic stress responses.
We then switched to the other

villain that people often talk
about and that's insulin.

So insulin regulation is very
critical for metabolic health

and we talked about the
importance of insulin

incentivity over absolute
levels, even touch on CGMS and

exercises profound impact on
glucose regulation.

From there we talked about
growth hormone Physiology,

specifically the scientific
perspective on GHS role in

recovery, metabolism and tissue
repair, and the evidence based

insights into training induced
hormonal responses.

I was also.
Curious what Sean's

comprehensive endocrine
assessment protocols look like

and his systematic approach to
biomarker analysis and high

performance individuals,
including optimal testing

frequencies and clinically
relevant markers.

We leave it at sex hormone
optimization across genders,

primarily talking about males.
He shares his professional

insights into testosterone and
estrogen function in both men

and women, plus the impact of
stress, nutrition and training

load on hormonal balance.
Now, without further delay,

please welcome Doctor Sean
Arndt.

Doctor Sean Art, welcome back,
man.

Hey, thanks for having me back.
It's always good to see you.

Yes, yeah.
Always good to to get the tech

issues out of the way.
I was looking back at the

archives man.
You were episode 4.

Nearly.
Wow.

It's not early.
Yeah.

I mean, it was like, what are
you guys up to now?

I think we just published 170 or
171.

Holy crap.
So now I'm feeling really old.

No, man, Last conversation was
highly entertaining, highly

educational.
So I do recommend that the

listeners go check that out.
We touched on a variety of

topics when it comes to
performance.

And here let me just set the
stage a little bit for the

audience and why I wanted to get
you back on.

I, I think as you're perusing
through social media, I was

maybe a couple months back and
you come across content and I

remember coming across a clip
where an individual was talking

about the acute effects of, on
growth hormone from certain

training style and was giving
general recommendations on how

this is the optimal way to
train.

And, and we've talked about how
there's never 1 optimal way,

right?
And this one was shared and

reshared and actually sent to me
by multiple people.

And I was like, OK, this is
something that really we should

spend some energy talking about,
particularly with the advent of

GLP 1 agonist and how much
attention people are paying to

hormones.
You have TRT clinics that are

popping up every block down the
street, and I think people are

really attuned to this, and our
son appreciates.

I couldn't think of no better
person who can come on here and

educate myself and our
listeners.

And just for context, we'll keep
this conversation centered

around performance.
I think if we start diving into

disorders and whatnot, we'll be
here for forever.

With that said, I thought we'd
start by talking about the one

that most people villainize the
most, and that would be

cortisol.
There you go.

And Sean, if I may, I'll even
say this to you that after I

graduated in undergraduate, I
spent a couple of years working

as a certain conditioning coach.
And even in that time in 2011 in

the fitness industry, there was
this notion that you got to keep

your workout to 60 minutes,
including the warm up because

you don't want that prolonged
cortisol response.

It's going to completely negate
any gains that you might have

accumulated.
And so I myself was a victim of

this mentality.
With that said, what do we need

to know a high level about
cortisol and we can go from

there.
So I think first of all, Kate,

let's say what is cortisol?
It's a stress hormone, right?

It above and beyond anything
else, it's a stress hormone and,

and it really plays a critical
role in fuel mobilization,

right?
And that's why the stress part

of it is a good thing and it can
mobilize resources when you need

them.
That's the whole idea.

And so it fits well with the
catecholamines with fight or

flight.
But I think what's really

important with understanding
cortisol is there is a very,

this hormone is very different
in terms of how we interpret its

presence, whether we're talking
about an acute or a chronic

effect, right?
So acutely, if you're doing high

intensity work, right, so you're
doing a hard resistance training

session, you're doing hell, even
if you're running for long

periods of time, cortisol is
going to be an important

modulator.
And all this acutely cortisol

mobilizes resources.
If we block cortisol with

dexamethasone during exercise,
your performance goes in the

toilet, right, Because you
cannot mobilize resources.

And it's funny because we've
done a lot of work looking at

the potential rule of a cortisol
threshold.

So where's this stress threshold
with different intensities of

exercise?
And when does it become more and

more important?
And well, typically, see

catecholamines show up first.
Cortisol being a steroid hormone

tends to come a little bit
later.

So we'd see ACTH or
adrenocorticotropic hormone show

up more during the workout,
cortisol kind of during the

recovery into that period of
time.

But I think what's often
misunderstood about it is

somehow the notion that cortisol
is bad and chronically this

could be very true, we'll talk
about that in a second, has

translated itself into the acute
part of it with exercise.

And so all of a sudden we see
these cortisol blockers and

manage cortisol and decrease
cortisol.

It depends on the context
because in certain contexts, if

you decrease cortisol, that's
not a good thing.

And even during the recovery
phase, cortisol is still playing

an important role in the
remodeling, in the recovery

that's going on.
One of the things that you want

to do is just be able to recover
from it a bit more quickly.

And we've done some work with
different supplements and things

like that.
And I think that the reality for

us is we weren't one of the
companies like, oh, it didn't

stop cortisol, You don't want it
to, that's a good thing.

Like you, you don't want to stop
cortisol, but you recovered from

it twice as quickly.
That was great.

Now chronically, this is a
different story.

If cortisol is chronically
elevated because you were

constantly in a high engaged
sort of high stress state.

Cortisol is a catabolic hormone
when all is said and done right,

is a catabolic steroids as
opposed to your anabolic

steroids where there's growth
involved with cortisol, its job

is to break down.
So if we have chronically high

levels of cortisol, the entire
system can fairly readily fall

into a bit of a state of
dysfunction, right?

Because we're not recovering,
we're constantly in the state of

breakdown.
So we want cortisol to follow

its normal patterns where it
tends to be at its highest as

you're starting to wake up,
right?

Actually proceeding waking up,
cortisol starts to rise to get

the body ready to wake up and be
engaged for the day.

We tend to see it stabilized
through about the middle portion

of the day, and then it will
start to decline or it should at

night, right?
And so one of the things we

often see is depending on
lifestyle factors, depending on

maybe how late in the day you
work out with high intensity, we

may push that cortisol curve a
little bit and not recover from

it quite as readily.
It's also the problem with short

sleep because sleep plays an
important role wherein that is a

time where the system is
recovering.

So if we start waking up too
early on short sleep, cortisol's

already started to rise, right?
It's doing its job.

This is a natural diurnal
pattern, right?

Follows are natural
chronobiology in that case.

And so with that in mind, really
having an understanding of

cortisol good, cortisol bad.
It's not that simple, right?

Because it depends on the
scenario we're talking about.

But certainly with exercise and
especially high intensity type

work, you want cortisol.
Cortisol is not the bad guy in

this.
Cortisol is an absolute

necessity for those high
intensity engagements.

Chronically.
We want to be able to recover

from it.
So we want ebbs and flows in

terms of when cortisol spikes,
when cortisol is at its highest

from a secretion standpoint, and
then to be able to recover from

that.
So I think understanding that

background to it, and I think
unfortunately, in an effort to

make money or villainize or
demonize certain things, because

now I can give you the solution
for it, I think cortisol kind of

fell into that and the media
really latched onto it,

especially the social media.
Cortisol in and of itself is

neither good nor bad.
It's a necessity, right?

It plays a fundamental
functional role for us.

If it's chronically elevated, we
don't want that.

If we block acute elevation, we
could have real problems, right?

So it, it falls in the, the
function part.

And it's interesting because
even dysfunctional cortisol and

really your HPA axis, so your
hypothalamic pituitary adrenal

axis, cortisol is part of the
end product of that entire axis.

And that axis is really a
hallmark of stress management,

stress response.
And when we look at that from

that standpoint, really that
dysregulation of that access is

a hallmark of stress related
disorders like depression, like

anxiety, even like PTSD.
And so it's not so much that

because cortisol is high or low,
it's that it's an inappropriate

response.
It's an irregular response to

how we want the body to
typically handle this stressor.

And so we see that with re
regulation of that access and a

normal cortisol response to a
stressor, we often see a bit

more of a re regulation of the
mental health side of it too.

So there's a pretty cool tie in
here in terms of what we see

across that spectrum as with
stress and stress related

disorders.
How often do you see a low

response to an acute stressor?
Maybe an athlete or somebody

where you're like, oh, you're
actually not responding the way

we should.
Yeah, we'll often see that with

overtraining, right.
And So what will often happen is

and it what it comes down to is
in the early phases of

overreaching and maybe early
stages of overtraining, it's not

uncommon to see a very elevated
cortisol response, especially if

you're measuring chronically.
But what gets really interesting

is as they get into this state
of sort of dysfunction where

it's non functional overreaching
or we truly get in to

overtraining, we may see
baseline cortisol high because

you never recover from it, but
your ability to elevate it

acutely is blunted because of
the ACTH response or the

arginine vasopressin response.
That's the other thing is so

ACTH is yes, the upstream
regulator of cortisol in that

whole axis.
But with exercise actually

arginine vasopressin is a more
potent stimulator of cortisol

than ACTH is in many cases.
So they go hand in hand when we

look at it from a stress
response standpoint.

My point in that is in these
phases where and it it's funny

because people that like to cut
to term that adrenal fatigue, we

got to stop using that man.
It's not even a real thing.

Like adrenal fatigue is not a
thing, but it's not that your

adrenal is worn out, it's that
you can't mobilize your

resources.
Your system is worn out or your

system is shot.
And so basically if cortisol

doesn't rise in that or rise
sufficiently, you can't mobilize

resources.
It's another way of your body

basically putting brakes on
everything, right?

You can't do this now.
And so we will see it in some

cases there.
I would say that we don't tend

to see that a lot.
And the reason I see that is at

least it from a research
standpoint.

I would argue that in the sport
science, human performance

world, we still have not
actually done a true

overtraining study.
They are very difficult to do.

However, we can take lessons
from studies that have been done

in the military with Army Ranger
training, some of the work that

Friedel and Nindel and others
have done, where they show these

hormonal responses under these
extreme stressors that we simply

can't replicate in the lab.
And so I think we've looked at

overreaching a lot more than
we've looked at overtreating.

That being said, there's still
been important lessons for how

resources get mobilized or not,
and at what point we just start

to see these chronically
elevated or suppressed

situations.
In this case with cortisol, it's

usually got chronic elevation,
but an inability to respond

acutely in the way that you
would think in order to be able

to do that level work.
So you mentioned highly engaged

high stress individuals.
I know a lot of people that

match that descriptor,
especially the guy in the mirror

when I look at it, what I
actually maybe before I ask that

question, I'm also curious how
often you'll see you mentioned

the highest response will be
preceding wake up in the

morning, right?
Or whenever time wake up is for

you.
Do you find that on an absolute

metric that is higher than any
type of exercise response?

But I shouldn't say any type of
the average individual myself.

If I have a hard training
session, can I even get it to a

level that would be higher than
my early morning levels?

And as a matter of fact, at the
very least, you can get it on

par with that.
And the reason I say that too is

we have done some work actually
when I was at Rutgers and we're

looking at overweight and obese
individuals and real

postprandial metabolism.
That's the background for this.

But we were comparing resistance
training to aerobic exercise in

order to help with that effect
on lipid resolution and

mobilization or, or metabolism.
And what we actually saw was

that those in the resistance
training group actually was

funny.
The cortisol peak in the morning

was prolonged because exercise
kept it up there for a little

bit longer.
Now what people might look at

that as a bad thing, but you're
like, no, it's just a hallmark

of when they were doing this.
And it was funny because

normally if we were to do that
work later in the day, like

midday, right?
So a lot of the times if we're

specifically looking at, and
I've done this for decades with

the work that we've done, if we
want to actually see the effect

of the cortisol response, we
will usually try to run people

between about 10:00 AM and 3:00
PM because it's when that level

tends to be most stable.
The reason that becomes useful

then is any fluctuation we tend
to see in cortisol becomes more

of a function of the response to
that stressor rather than

influences of the normal diurnal
variation of highs and lows.

So it's a bit more stable.
We have to control for meals

because of that because meal
timing can influence this as

well.
But that's fine.

That's not that hard to do.
But certainly at short times of

the day, yeah.
And you can might, you can Jack

cortisol up, you can get it to
these pre wake or early waking

levels.
Question is how fast you recover

from it.
And there's certain training

modalities or certain stressors
that may do it more than others,

but cortisol has a tremendous
ability to rise acutely and then

recover if you give it the
opportunity to do.

Yeah, that was Patrick's study,
right that you're talking about.

So yeah, exactly that.
Yeah.

Pat Davitt.
Yeah, Pat Davitt, me, Pat Davitt

and Greg Henderson all worked
on.

That yeah, yeah, I remember that
I was in live with you at that

time That's right I so coming
back to this chronic response

elevator response which a lot of
people experience.

I think the world is chaotic to
say the least nowadays.

And you you highlight a social
media had a lot of good, but

certainly a lot of bad there
too.

And it can elevate the stress
responses.

People tend to stay up late at
night.

You're sleeping less and less
kids spending time earlier on in

those really developmental
years.

And suffice it to say, people
could use some strategies to

manage some of these.
I don't want to say cortisol,

I'll say stress.
So with that said, what do you

think the lowest hanging fruit
that people should be thinking

about when maybe before even I
say that, what would be a good

way to assess or some size that
might be like, OK, maybe

something is going on and this
needs to be looked at or, you

know, rather than just
subjectively, I'm a high stress

person, I'm a, I'm in a high
stress job.

Are there subtle things that
people could think about that

might suggest that that this
needs to be addressed in the

first place?
That's a good question.

So I think there's a few things
paying attention to feelings of

chronic fatigue.
So not chronic fatigue syndrome

per SE, but just always being
tired right from that standpoint

or this feeling of being
overwhelmed or anxiousness that

kind of go along with these
things too.

And how is that sitting with you
to do this?

But I think the other thing too
is from a simple metric to track

as well.
Are you seeing changes in your

resting heart rate, especially
upon waking?

Is it starting to trend up if
you are wearing a wearable?

What are we seeing happen with
HRV over time?

And so like that and HRV would
be a whole another topic that we

don't want to get into today.
But to put in simply, much like

cortisol, it is oversimplified,
but I think that the reality is

when you start seeing these
indicators that that you were a

little off or you're starting to
realize that you, for lack of a

better way to put it, you feel
stressed, right?

You just feel, and I would say
probably the better word is you

feel distressed, right, 'cause
stress is another thing.

Cortisol where stress gets a bad
rap.

Without stress, we die because
stress challenges the Organism,

forces us to grow and forces us
to develop and adapt.

So it's not that stress is bad,
it's the distress, the negative

influences, especially the
things that aren't under our

control.
You need a little bit of that

learned helplessness that goes
with that, things like that.

But I think when you start to
look at the nature of the

stressor and really sometimes
the compounding of stressors,

this was a really useful lesson
we learned working with

athletes.
Again, when we were at Rutgers

and we were working with the
women's soccer team, I think we

got pretty good at controlling
training load.

We're pretty good at controlling
the training itself, lifting

even some of the nutritional
stuff.

I started to realize, man, we're
still missing big pieces of this

puzzle from a human performance
standpoint because we're

counting for two hours of the
day what's going on in the other

22.
And this is when we're working

with Quest Diagnostics and their
blueprint for athletes.

And we started to be able to do
these biomarker panels and

really in some cases, looking at
the inflammatory and the stress

responses and stress hormones
and realizing that besides just

playing soccer, you've got
classes and you've got

relationships and you've got
environmental factors, you've

got team dynamics.
There's all the travel, right?

And all of a sudden we started
to capture the other 22 hours of

the day.
And funny enough, that year we

started accounting for that was
the first year the team made the

final four, right?
And it was one of those where

we're able to start to
consolidate this.

But we started to pay attention
to those little things.

How were the players feeling?
How were they performing, right?

So that's the other thing too
is, you know, if you're

exercising and you start to
notice that your efforts in the

weight room, your efforts
running, cycling, whatever your

jam is, Olson, it starts to feel
a lot harder.

If you see your performance
declining, might be time to take

a look at what's going on around
you from the standpoint of is

your system not able to adapt
and repair in a way that

facilitates this continued
improvement or at least a

maintenance of performance.
So paying attention to those

little things when they feel
off, I think is important.

There are certainly some days
where you might just get trained

through the suck, right?
There's just some days you're

not feeling as much as others.
We don't want to take all those

days off.
But I do think it's important to

listen to your body and know
when you might need some extra

rest, especially if you're
operating on short sleep

chronically.
There's going to come a time

where you're going to have to
make up for that, right?

Otherwise, the system's in a
state of disrepair.

And not that all of it is
because of cortisol, but

continued elevation, that is not
going to be helping you either.

Yeah.
And to come back to your point

about monitoring your some of
those HRV resting heart rate and

I know a lot of people wear an
Apple Watch or a ring.

Now people have 8 sleep as well
which will check those metrics.

I think something to mention to
people about that is you want to

look at trends, right?
So if you.

Are right, Yes.
And if you're especially if

you're going under the weather
and you have a cold, not a good

time to be looking at your
elevator heart rate, a couple of

BPMS and say, hey, that's
contributing to that.

Something else that actually
comes to mind, I think one thing

we know is different hormones
will influence our body

composition in various ways.
We're going to touch into that.

We also know that like for
instance, I'm getting ahead of

myself here, women because of
their hormonal profile will tend

to put adipose in different
parts of their body.

Sure.
I remember at some point

learning that one sign you
mentioned it's a catabolic

hormone.
So if you're not able to put on

any muscle mass, if that's a
goal, and as you mentioned that

you're not able to do that
despite being fatigued and

you're like, hey, man, my, my
sleep is relatively dialed in.

I think my nutrition is somewhat
on point.

I'm training hard.
I'm not able to get any muscle.

And presuming any of the other
hormones are still normal.

One thing that I remember people
talking about is that if you

tend to put a lot of adipose
tissue around your belly,

particularly for males, that
might be a sign of elevated

cortisol as well.
Is that is there any truth to

that?
Yes and no.

I don't want to dismiss it
entirely because it's funny.

There's some fairly high, highly
respected scientists, one in

particular I can think of that
they like to say that cortisol

has nothing to do with making
you fat.

Cortisol's a catabolic hormone.
How could you possibly store

fat?
So one of the things that we see

is even though cortisol doesn't
always directly result in this

body fat accumulation, it is a
catabolic hormone.

I get that.
But there is some pretty strong

evidence for cortisol's role in
adipocytes being more sensitive

to being able to store fat.
It also plays a role in

cholesterol synthesis and
cholesterol in in cortisol or

yeah, in terms of how they
interact.

And so there can also be some de
Novo lipogenesis that occurs

with that.
So making new lipids for

storage.
Yes, chronically high levels of

cortisol, though it is a
catabolic hormone, there is some

pretty compelling evidence for
the role that it can play in

increasing fat storage
capability.

And some of that may be somewhat
through the loss of muscle and

things like that.
And again, separating out acute

versus chronic effects is very
important there.

So with that chronic elevation,
there's a sensitivity with some

of the beta receptors that
occurs that that seems to favor

some of that fat storage.
And certainly because of where

some of those receptors might be
located, that more central

adiposity would not be uncommon.
Now I will say this though, it

gets a little bit compounded and
I think people have to be very

realistic with themselves
because there are some

situations where in this sort of
high stress and not just

psychological stress, but other
high stressor situations where

cortisol may stay elevated.
What other lifestyle or

behavioral factors may be
playing into that fat

deposition?
Because it could be that you eat

in response to that.
And cortisol itself can also

change certain cravings for
different people, right?

In terms of what they're craving
to handle it because of this

that the chemical signals to the
brain it it's probably not a,

it's not a super simple
relationship where cortisol

makes you fat.
It's more like cortisol is

indicative of a situation that
can lend itself to storied body

fat.
And cortisol itself can also

play a role in this, right?
So it's a, it's a, it's a

mediator as well as a direct
causal factor.

And you layer those onto each
other.

Now, the caveat is when you
think about how long it takes to

put on weight, and some gets
especially stored fat, if you

wait until you put on enough fat
that you noticed cortisol might

have been elevated for quite a
while in terms of some of that.

So I don't know that I would use
that as my benchmark in terms of

my first one.
But for a lot of people, that

may be the first time that it
makes them sit up and take

notice.
They're like, what is going on?

I can't lose weight.
I'm weight stable, but I feel

like I'm getting fatter, stuff
like that.

Yeah.
All those things may be triggers

to look at everything else
that's going on.

And it may be that cortisol is a
symptom of what the whole

process has been in order to get
you to.

You mentioned beta receptors,
what are they located in every

organ or certain?
Yeah, So certain and certainly

depending on where they're
talking beta 1, beta 2, beta 3

receptors and the role they play
in lipolysis and things like

that in terms of and again
catecholamines will play a

pretty big role there as well.
We see it at the muscular level,

at the adipocyte level and
things like that.

So even the the receptors
themselves that are responsive

to the stressed pathways and the
chemical signals that go with

that can also play a role here
too in terms of whether we're

talking like polysis or
lipogenesis, how that fits

together.
Those are interplaying pathways

that make a difference there.
We highlighted that sleep is

very important and we've talked
about sleep multiple times, so

I'm not going to dive too deep
into that.

But you did mention earlier with
that obesity study that we were

working on together that we had
to control for nutrition.

Yeah.
Say a little bit more about

that.
How does your nutrition either

blunt or elevate that response,
if at all?

It probably has more to do with
where it's going to tie in for

the entire system recovery.
So it's not necessarily that one

food source will magically raise
or lower cortisol.

It's going to be the overall
effect on the system in terms of

fuel mobilization, but also
where the storage is occurring

with poor nutrition.
And we're looking at a situation

where we are not optimizing
muscle protein synthesis.

We may favor de Novo
lipogenesis.

We may be looking at things that
do not lend themselves to an

otherwise ideal body composition
outcome or performance outcomes.

In that case, diet's going to
have an influence because diet

does play a role in your
exercise performance, having the

right food sources.
Here's The thing is, there's

been a couple studies now and I
think people forget this at

times, but even the role that
the macronutrient make up.

But if somebody's on say a
ketogenic diet, in order to

allow for those fats to become
glycogen in order to be able to

be used for other intensities,
the entire hormonal system is

going to play a role, including
insulin, Glucagon, cortisol,

piata, They all play a role in
influencing that response.

And if you're not adequately
recovering and it's, you know,

for example, there's some cool
studies where they've actually

shown that with carbohydrate
refeeding after intense

exercise, you can actually help
reduce the court, the

catecholamine response to, to
facilitate recovery faster.

And catecholamines and cortisol
will also feed off each other,

if you will, in terms of the
things that typically influence

their secretion and their
overall responsiveness.

So again, that dietary influence
is important in making sure

you're providing the raw
materials.

So the cortisol doesn't have to
continue to break down your

body's resources in order to
provide it otherwise, right?

Because in the absence of
feeding with protein and things

like that, the body will find a
way.

So it'll breakdown muscle tissue
in order to provide amino acids.

That's something that cortisol
is very good at.

So if you're looking at
cortisol's role in that, again,

it's mobilizing fuel, it's
mobilizing resources.

Yeah, we've mentioned
catecholamines a couple of

times.
So just for those listening, So

we're talking about
norepinephrine, epinephrine,

dopamine, right?
Anything else OK.

Cool.
No, those of you and really the

typical when we're looking at
the exercise response, MP and

nor MP are your two primary
drivers.

But certainly dopamine plays an
important role here within other

factors that facilitates that
too.

But yes, and for those that
might be listening in Europe,

we're talking adrenaline and
noradrenaline.

So just depends on where you're
from, but same idea.

So two-part question for you.
When you're working with high

performance individuals, not
just athletes, but cognitive

performance, I'm putting it all
in the same bucket.

One, what's your assessment
process like?

What labs are you looking at,
again from an optimization

standpoint?
And then two, all the levers

that we can pull out, right?
Stress management, sleep,

nutrition, exercise.
Where do you like to start if

you do find that is not in that
optimal window?

So there's a couple things here.
One, I almost never like to look

at those biomarkers in isolation
without also knowing training

load or other stressors that are
going into this.

And the reason is you may see
these values come back.

And the next question is now
what do I do about this?

If you don't know what's been
going on, you have no idea where

to start with modification.
All you know is these values

look off.
And the other thing too is I

rarely, if ever, will rely on a
single time point in this case.

What's so important for me when
working with these really high

level performers is change over
time, right?

Because there's such individual
variability there.

So having more than one data
point becomes really useful for

tracking how they're responding
because that way if we modify

their training, their diet,
their sleep, any of those sort

of major drivers, I need to know
that they're working.

Like how is it working?
What's it doing?

It's typically when we start
looking at blood panels part

that's going to depend on what
the question is we're asking.

One thing that I've learned to
appreciate these panels more and

more for is the role in the
nutrition piece, right?

And that may be the one place
where you can do a single

snapshot, get a good idea for
where somebody's status is.

When you look at iron ferritin,
when you look at Omega threes,

omega-3, 6 index, when you start
looking at magnesium, when you

start looking at those different
actors that you can get at with

some of the important vitamin
and mineral relationships, the

iron storage and things like
that, that that go into it,

especially for a lot of our
female athletes, that becomes

really useful.
But again, looking at that over

time and if we're going to do a
dietary intervention, we want to

know that it's moving the
needle.

How is this actually modifying
what we think needs to be

modified?
But other than that, typically

unless I'm working with a pro
team or athlete where the

collective bargaining agreement
stops me from looking at these

things, I'll typically include
cortisol, both free and total

testosterone free and total
growth hormone IGF.

One, a few inflammatory markers,
especially Illinois 6, we've

been using CRPA bit more
recently in terms of we tend to

find it to be a fairly reliable
marker over time in terms of

what we're looking at TNF alpha
if I need to, but Illinois 6 and

CRP usually give me a pretty
good snapshot for most of what

we're doing with that.
Certainly if you're looking at

your conference of metabolic
panel and your CBCS to be able

to get at some of the immune
markers, but then also looking

at hemoglobin and hematocrit,
looking again at iron and some

of the things that may be
indicative of recovery.

I don't typically have caught up
too much in some of the liver

enzyme markers unless there's
something else going on because

exercise so heavily influences
them.

So in almost every athlete, we
typically see AST and ALT

elevated and we don't freak out
about it because their last

workout probably influenced
that.

But again, we track these things
over time.

We've done growth hormone.
We've definitely found to be

more responsive in females as a
marker of what's typically going

on.
We'll typically look at

estradiol and progesterone
depending on the questions we're

asking with a female athlete
study in particular or any

changes we may see there.
Although we've also tracked

estrogen in Med looking at some
of the changes throughout a

season, especially as they
counter counter respond to some

of the testosterone influences
and things like that.

Those are some of the ones we
rely fairly readily on.

The other one that I have found,
the other grouping that we use

pretty routinely are the is the
thyroid panel.

And unfortunately, a lot of
times if you just go get it

tested, they might test like TSH
and T3 or TSH and T4.

Ideally in that population, I
like TSH, the thyroid

stimulating hormone, T3T4 and
reverse T3, right?

And so that, and I think that's
missed way too often.

We'll also look at the blood
lipids.

We've got some really cool data
in both athletes and in dancers.

So like artistic dancers, so
elite ballet performers and they

often have like higher blood
lipids, but it's also often

associated with low thyroid.
And people forget that thyroid

helps modulate and metabolize
these lipids.

And so if thyroid is not
functioning appropriately

because of, say, low energy
availability or any of those

things, we may be looking at a
situation where we can see

cholesterol rise.
And so looking at those markers

tends to be very valuable.
And we've been using prolactin

more and more.
I'm finding prolactin to be a

very responsive stress hormone,
much in line with cortisol and

in some cases, a bit more
predictive for some of our

studies for performance
downturns.

And it turns out the prolactin
responds incredibly well to

stress and it's fairly
indicative of it.

And so using that in conjunction
with some of our other stress

hormones, including the
catecholamines, another thing

that we look at.
But again, I can depending on

the financial resources of an
athlete or an organization, that

might be my ideal panel that we
would look at, but we can scale

it based on what's available.
The one thing I don't do, and I

often I get asked this a lot,
especially by like strength

coaches, like if you could just
pick one marker, what would be

where be cortisol.
I'm like honestly, like it's

hard to just pick one marker
because they tell you different

things.
And so could you come up with a

panel of say 5 to 8 key markers?
It depends on the question

you're asking and how closely
you want to monitor.

We've probably boiled it down to
about 10 to 13 that we can

reliably use to track over time.
There's others I like to use

when we have the resources to do
it.

And I think in some ways I would
rather use those that have been

indicated implicated in health
and performance, but use them on

a very routine basis.
So I would rather go for

frequency over breadth of that
panel because it gives me a

chance to do something about
them.

So ideally, a perfect situation,
roughly every three to five to

maybe three to six weeks, we'd
be able to track this,

especially in season for
athletes.

Offseason, maybe we can go a
little longer, depends on what

we're trying to do in that
offseason.

But we found a sweet spot around
4 weeks without it being overly

invasive and overly expensive,
but frequent enough that we can

influence training and
preparation.

For SO, most of the things are
blood biomarkers, but my

understanding is for cortisol
specifically, either urine or

saliva is preferred.
Which one do you like?

I wouldn't say it's preferred.
I saliva's easy.

So salivary markers correlate
well to the blood markers if

we're looking at serum, but
they're lower, right?

So your concentration, you can't
compare the concentrations in

that case.
So whatever you start with, you

need to stick with because I
can't compare those fluctuations

across blood and saliva.
So that's an important caveat to

that.
I prefer blood for cortisol

simply because I get all my
other markers at the same time

instead of having to run a
completely separate assay or a

separate analysis in order to do
that.

But we've used saliva a lot.
We actually did a really big

study with the Marine Corps
looking at gender integration

that we just completed.
We had a bunch of publications

come out this, but we were able
to use salivary cortisol during

recruit training in order to get
that.

Cause not like we're going to do
blood draws on hundreds of the

recruits all at the same time,
but we could collect saliva on

everybody at the same time.
So some of it depends on which

tool you're trying to employ,
depending on what the toolbox

needs are at that point, but all
of them work.

I think I've seen less that
convinces me on the value of

urinary cortisol.
We use urinary catecholamines

though.
But again, it depends on when

you're getting first catch of
the day and how you're

interpreting that over time.
But mostly with cortisol, we

relied almost exclusively on
either saliva or blood.

Gotcha.
Coming back to the prolactin

really quickly, you said
elevated in times.

Or is it?
Yeah, it is.

It is in.
As the season goes along, we'll

often see deflection in it as
they're having a harder time

mobilizing resources to to
handle the stress of the season

and those that are starting to
see a performance downturn.

But by and large, yeah, we do
see a rise in it.

Interesting, I never heard that
before.

Cool, I'll look more than that.
Anything else to say on this

specific hormone before we move
on to do maybe the next biggest

villain that I hear about?
No, I think cortisol has helped

shape my career.
That's what I started, the main

hormone I studied, and it just
has followed me throughout my

career.
Yeah, love cortisol.

It's good.
It can be good, but we want to

control it.
Yeah.

And to your point earlier about
people trying to block it, I

think I'm pretty sure if you
don't have cortisol, you die.

So.
Yeah, pretty much.

It's bad.
Yeah, so insulin's been in the

limelight quite a bit.
And I think the probably Doctor

Jason Funk's book, I think the
Obesity Code, good book, maybe

some issues in it and shed a lot
of important, shared a lot of

important insights and talked
about how hyperinsulinemia can

maybe really be the Canary in
the cold mine when we're talking

about diabetes, obesity.
That's something that's very

important for us to talk about
because yeah, in about 5 years,

the expectation is that 50% of
the American population is going

to be in that category.
And so that's scary.

So with that, there's also the
concept that insulin actually

turns out, my understanding, is
the most anabolic hormone out of

all of them.
That in IGF one, I would put the

two hand in hand, but IGF one is
insulin like growth after they

go together, but it it's job is
storage.

So now does it mean it's going
to make you the most muscular?

A little bit of people think to
be anabolic that way.

Anabolic is about growth, right?
So insulin does an amazing job

at storing.
That is its job.

So.
So let's talk about insulin.

What is it that people need to
understand about insulin and why

should they not be terrified of
it?

Insulin and Glucagon, OK.
So those are your two counter

regulatory hormones from each
other and insulin helps with the

storage of glucose, Glucagon
helps with the mobilization of

glucose in the system.
In order to handle this and keep

blood glucose fairly stable,
insulin is going to primarily

respond to a meal right after,
especially a high carbohydrate

meal.
But we also see a fairly

significant insulin response to
amino acids, especially free

form amino acids versus a whole
protein source.

So insulin response to a meal,
it helps with storing that.

Now, insulin can affect the
storage within the muscle or

with lipids, right?
It can impact storage with

adipocytes.
So insulin is important for

helping to regulate that blood
glucose.

But we don't want, and I hate to
use this term, but it's the best

way right now.
We don't want too much insulin.

What's too much?
If you're at that

hyperinsulinemic stage and it's
chronic, we've got a problem.

But I think there's been such an
an emphasis lately, especially

with like continuous glucose
monitors and stuff where it's

like keep your insulin stable.
To be honest, we handle

fluctuations in insulin just
fine.

Like we're designed to do that.
So it'll go up, it'll come down.

That's not abnormal.
The problem is when it goes up

and stays up.
And that can be actually funny

enough.
We were just talking about

stress.
We see that with stress as well,

funny enough, because of some of
the influences we have on tissue

sensitivity.
But ultimately we would like to

be sensitive to insulin.
And what we mean by that is not

that you don't secrete insulin,
but simply that it doesn't take

as much to do the same job.
And when we become insulin

resistant, so we have to
chronically increase the amount

of cortisol that we secrete in
order to handle whatever that

nutritional load is.
And things like.

That's where we start to run
into problems.

But I think science has largely
debunked the insulin hypothesis.

That is the whole reason why
we're fat.

It's the insulin is associated
with a lot of the behaviors that

dietary behaviors that
contribute to that as well.

So is it insulin doing it or is
it the factors that influence

insulin that are doing it?
And I think it's more of the

latter.
But certainly these chronically

high levels of insulin are not
ideal, but it also doesn't mean

that we certainly don't want to
block insulin.

But getting a sense for in
what's funny is what's

interesting like with the CGMS
and with this emphasis on

regulating insulin or whatever
is honestly, even in the same

person, the same meal doesn't
even always cause the same

insulin response from
day-to-day.

There's variability in how we
respond to that.

And that's OK.
And so we start to look at how

that influence occurs.
But yeah, insulin is one of

those things we should pay
attention to it.

If you have high resting
insulin, that may not be a good

thing when we start to look at
it, But and it often goes hand

in hand with high glucose.
And This is why, for example,

looking at hemoglobin A1C as an
indicator for these chronically

high levels becomes fairly
useful when we're looking at

glucose regulation, but
insulin's important for that

regulation.
What might influence those

variations?
And a person.

Same meal, same person, just
different day.

There could be other factors
around the day in terms of the

timing of certain things.
There could be influence of

other dietary components prior
to that may still be changing

the metabolic response.
Some of it is welcome to being

human.
I think we're an incredibly

complex yet awesome system when
you look at how we function.

And so some of it is will be
influenced by, for example, your

workouts, some of it will be
influenced by your sleep, some

of it be influenced by the diet
itself.

So there are a lot of things
that can do that.

And it's also just the simple
fact that these minor

fluctuations, probably not a big
deal, Like it's just simply our

ability to be flexible in
response and handle what's

thrown at us.
And when we start to become

irregular in that flexibility or
extreme in those responses, that

might be where we have a little
bit more of a problem.

Because if we can make a bunch
of small, little minor

adjustments to maintain
homeostasis, the system loves

that, right?
That works pretty damn well.

But if we start to require these
big changes in order to get

there, that's where we get a
little bit more system

disruption.
How does our body respond with

insulin to training, both
resistance training or aerobic

training?
During the training itself, it

should go down, right?
So basically it was when I teach

my exercise endocrinology class,
we kind of start by saying, OK,

I'm going to wrap the whole
semester up like this.

When you exercise, everything
goes up except insulin, which

comes down done right there.
We're done with the semester,

right?
That was easy.

Insulin should not be high
during exercise because exercise

itself activates the glute for
transporter.

So glute for transporters are
embedded within muscle itself

and they're responsible for
transporting glucose into the

cell to convert it to glycogen
or to shuttle it through from a

bioenergenic standpoint through
glycolysis and potentially on

through oxidative
phosphorylation.

What happens is during exercise
then because exercise is so

glute 4 transporters are insulin
dependent transporters.

They respond to insulin.
For example, after a meal as

insulin goes up, it will turn on
these glute 4 transporters.

They translocate to the surface
of the cell.

They can pull glucose up.
However, those gluten 4

transporters also respond to
something besides insulin, which

is physical activity, muscular
contraction.

And so exercise itself favors
being able to pull glucose from

the blood into the muscle cell
itself to be able to use for

energy to use for storage after
if we do that.

But the reality is in that case,
then insulin goes down.

Glucagon should be going up to
counter this, and they tend to

do it in balance with each
other.

So as insulin's falling,
glucagon's going up with chronic

exercise, though there is good
evidence that with both

resistance training and aerobic
exercise, both of those increase

our insulin sensitivity, they
reduce our insulin resistance.

So now those same transporters,
the receptors that are

responsive to insulin are more
receptive, they are more

sensitive to its influence.
So we don't require these big

swings to produce the same
effect.

And that's why, for example,
exercise has become a first

level treatment or intervention
for type 2 diabetes because it

helps manage blood glucose
levels because of what it can do

to insulin sensitivity.
Yeah, you earlier you mentioned

that your stress or whatever
you're experiencing, we talked a

lot about cortisol can actually
affect your tissue sensitivity

to both glucose and insulin.
I remember writing A blog post

maybe 10 years ago about how
there were some studies that I

was reading where one night of
sleep deprivation raised the

average glucose level to like
somebody in in the diabetic

range or pre diabetic range.
And I think those types of

things have been demonstrated
multiple times.

What what do we need to know
about that?

The tissue sensitivity being
altered because of distress, as

we said, or more sleep and that
kind of stuff.

Yeah, and it really does.
And there's actually been, it's

funny, you wrote that blog like
10 years ago.

But The funny thing is there's
been a couple studies that have

come out recently showing what
just one night of sleep

deprivation can do to not only
cognitive function and things

like that, but certainly the
other markers of metabolic

dysfunction in terms of how we
process and handle most of our

food sources, macro nutrients
and things like that.

And you're right, it it
resembles almost this sort of

pre diabetic state in terms of
what we do.

Now, what does that mean on a
day-to-day basis?

Ideally you're never sleep
deprived.

But unfortunately in this
society and among other things,

it's going to happen from time
to time.

But I think it points to the
problems with that being a

chronic pattern because again, a
day-to-day fluctuation in that,

not going to panic itself.
Oh man, you only slept for five

hours last night.
I'm sorry, today you're

diabetic.
We got to start you on

Metformin, right?
That's not how this works.

But if you let that go on long
enough where stress is

consistently high and you're not
handling it, where sleep

deprivation is a real
consideration, or at least sleep

restriction more so than
deprivation, that's probably

fair.
You start to look at a situation

where it does set the system up
to become more resistant and

less sensitive to these
influences.

And I think that is one of the
beauties to exercise, proper

diet, proper self-care, is that
we can actually change the

sensitivity of tissues in a
positive way to be able to

prevent these massive
fluctuations in hormones,

especially at rest, in order to
handle these things and recover

from them a bit quicker.
So yeah, that that chronic

influence is something that we
would consider.

Again, it's much like the HRV
and the heart rate stuff.

Don't let one day freak you out.
Don't panic about everything

just yet.
That one day where these things

changed.
And I think that's maybe it's a

blessing and a curse to the way
people are using CGMS because

continuous glucose monitors for
somebody who is diabetic, I

think are fantastic.
For somebody who's not, we have

yet to really see anything that
shows there of any true value to

them.
And as a matter of fact, they

may provide an overabundance of
information that just gets

really noisy and makes it hard
to interpret.

And I think the reality is in
all this stuff we're talking

about all, I think that the
reality is if you pay attention

to too many of these inputs, you
wind up with a lot of noise.

And I think one of the hardest
things to do in this area, and

maybe one of the things I enjoy
about it, but I see being

oversimplified through social
media and stuff like that, is

some of this isn't quite as
simple as people like to make it

out to be because you got to
know the context around it and

the other influences that go
with it.

And I think that is the reality.
And so yes, all of these things

start to play in the same
sandbox when that starts to

happen.
What about using it for a brief

period of time as an educational
tool?

Absolutely.
In that case, especially

depending on who you're working
with.

But again, for an otherwise
healthy individual or honestly

even for an athlete, I'm not a
big fan.

I don't think that it helps as
much as people think.

The people I often see promoting
that are the ones that really

think ketogenic diet is the
answer to everything, who think

that insulin is the bad guy.
It's this evil little demon

somewhere that's doing all this
bad stuff.

There's a lot of stuff that I
would probably utilize for

educational purposes before
that, given the burden it

places.
Not to say there's no value to

it.
I think I try to look at it from

a sports science standpoint.
I try to look at the big rocks

first.
What are the things that are

really going to move the needle
and to be honest, the

fundamental dietary influences,
the ones that we know work for

performance using select
biomarkers to be able to track

where your changes are occurring
or where your deficiencies might

be.
Those to me will be infinitely

more powerful because they are
getting at the core of the

entirety of the Physiology
versus just insulin in this

case.
And so I think with the OR or

even glucose and glucose
modulation, not that glucose

responses aren't important, but
I can influence those a dozen

different ways, right?
We influence them with activity.

We influence them with diet, we
influence them with sleep.

So it depends on what level of
noise we're willing to endure in

that.
But I think if employed properly

and in the context of what we're
already doing, well, could be a

useful addition.
Would it be my day one?

No.
Now, if you're working with a

type 2 diabetic or even a
diabetic athlete, like a type 1

diabetic athlete, those can be
absolutely life saving, right?

And they can then really help
you tweak your dietary

interventions around those
athletes and especially around

that type one.
But for an otherwise healthy

athlete, I don't think that's
where I'm going to start.

Yeah, that's fair.
I will say though, just from the

Hawthorne effect, if you have
the resources, it could be a

very powerful tool.
Oh, no, I don't disagree with

that.
And that's what I'm saying.

Anything we can do to get people
to pay attention to their

behaviors.
So to me, it's like when you

talk about like fat diets, do
they follow intermittent

fasting, paleo diet, keto, blah
blah.

At the end of the day, what they
all force you to do is look at

what you're eating, right?
There's this factor of you're

paying attention to your diet
and what almost all of them have

in common is removing a lot of
processed stuff.

So was it the diet or the impact
of going on that diet that made

the different, the difference
there?

And I would say same thing with
CGMS and things like that.

Shit, even the same thing with
or rings or whoops or anything

else is if it makes you pay
attention to some of your

behaviors, that can be a really
good thing.

Just we need to make sure that
we're using the technology and

not that the technology is using
US, right?

So your decision making around
that needs to be within the

context of how everything else
is, right?

Because there's been days like
on aura, bipolar, whatever,

you're going to die today if you
work out, but you're and I might

have the best training that day
than than I ever have.

And I'm like, yeah, I knew I
felt fine, like I felt good.

And so there's just simply days
where, you know, as an athlete,

as an avid exerciser, things
like that.

Pay attention to you as well.
Don't just go off the metrics.

Use those in combination with
the rest of what 'cause there's

some days too where I'm like,
man, I got 4 hours of sleep last

night and it's like your
readiness level is fantastic and

I'm like, I am not training
today.

I'm exhausted.
That is a bad idea.

So again, using a little bit of
common sense with this, use the

technology, not the other way
around.

So do you think people are in
tuned enough for their bodies

that could be reliable?
And I especially think about

college athletes.
I think about myself in college,

I could sleep 4 hours a night,
every single night.

I'd be ready to go the next day.
And of course, yeah, when you're

20 years old, like that doesn't
affect you as much.

But I just, I don't find it when
I see people, when I'm talking

to people that they are really
understanding what's going on

with them.
And you know what?

It's a great point and it's
because we're not helping them

understand what to listen to.
So what I mean by that is we've

worked with athletes over the
years and it's funny, I step

back and we often make this
assumption.

College athletes that must be
great to work with these high

fours.
I'm like, dude, some of them

know nothing, right?
And so we would be starting to

do like sport nutrition stuff
with them.

And we realized they don't know
the difference between a carb, a

fat and a protein.
Like we're starting with

fundamental nutrition.
You're not even going into the

differences in carb sources.
You're just this is a carb, this

is a protein.
OK, good.

Let's work on that first.
What we have generally found is

athletes often exist in a state
of fatigue without knowing

that's not normal, OK.
And So what we'll typically do

is, and this is where some of
these other markers become very

useful to educate them.
I love how we've been able to

use training load, for example,
to help athletes understand what

they need to replace, right?
When we were able to get female

athletes to start associating
their training load and caloric

expenditure, not with, oh, good,
I'm going to lose weight with,

but with, oh, I need to eat to
replace this now if I want to

perform.
Amazing response, right?

That is like you're now using
their own data to help them

understand.
And that's how we've used

biomarkers.
We use their data to help

educate them.
And what would happen is if you

do the right things, if you pick
the big movers, the big rocks,

What's funny is the number of
them that will come back and be

like, I can't believe how good I
feel.

I didn't realize.
I just thought that the way I

was feeling was just 'cause I
train hard and they're like, I

don't have to be exhausted all
the time.

And we've had athletes.
It was funny, actually, one of

the athletes that Michelle works
with.

So for the listers, my wife's
the director of Olympic sport

nutrition over at University of
South Carolina athletics.

Anyway, one of the the track
athletes she was just working

with just won a silver at
worlds.

And he didn't realize how much
better he could feel, but he

made the commitment to wanting
to do this.

So he started to pay attention
to how he felt after doing these

different things from a dietary
standpoint, for recovering from

his training and all that stuff.
And he showed up, big smile on

his face, to show her his mettle
when he got back because it made

a difference.
So I think what's key in this is

help them understand what to
listen to, 'cause you're right,

man.
I think back to college, the

number of games and practices
that I was functional for is

probably a small miracle at
times, but I think at that age

you can play through a lot.
What has been really revealing

to me is especially the more I
worked with pro athletes and pro

teams, the athletes that always
had the most questions were the

ones that were at the tail end
of their career.

And their question was how do I
get another year?

How do I get 2 more years?
How do I get one more contract?

And what started to happen is
the younger players started to

pay attention to that a little
bit because the older players

could be like, you don't
understand, there was a lot I

could get away with when I was
your age.

I wish now that I would have
known more of this.

Then I would have actually
probably been even better.

And so I think we're seeing a
shift there.

But I think teaching these
individuals to start to listen

to their body and pay attention
to how they feel is something we

don't do enough.
We throw numbers at them, we

talk to the coaches and stuff.
But I think sometimes with the

athletes, every once in a while,
just have that conversation,

Hey, how are you feeling?
You know, how are things going,

what's going on?
And using their own data to help

them understand where they're at
their best and where they're

not.
That's why, to your point, CGM

or otherwise, if we have a tool
that helps them dial in and

focus on them, we can help them
start to understand how did you

feel during this period of time
too?

How did you feel when you ate
this before a game versus this

before a game?
It's just getting them to pay a

little bit more attention.
Because I think you're right.

Without that guidance, though,
it's easy to go on and be like,

Nah, you can cut through
anything.

And I think that what we're
trying to get them to do is one

thing I've learned with athletes
and with military operators,

like if you're working with
special forces, those guys are

unique, right?
Because at the expense of

anything, they will make
mission.

That is their whole goal.
What we want to be able to do is

help them do it in a way where
they come home alive and in the

case of an athlete, where they
feel good being able to do it as

well and they can really
maximize their potential.

What I found is, it's funny, one
of the definitions of

overreaching is that you should
see a performance downturn.

I've generally found that is not
accurate because there are a lot

of things that an athlete or an
operator will find a way to cut

through.
It just feels a hell of a lot

harder than it than it should or
than it used to.

And so it's that dialing into
what's happening to performance

and how you're getting there
that I think we need to pay a

little bit more attention to.
Yeah, I to your point about

athletes and I think the hitting
the genetic lottery probably

helps a lot.
I remember.

Big way, absolutely.
If you want to be an elite

athlete, pick your pair as.
Well, I remember listening to an

interview with DK Metcalf then
maybe a year or two and he

talked about, Oh yeah, like he
doesn't eat his first meal till

4, which is like a big and it's
not a meal.

It's like a Grande latte or
something from Starbucks.

And then he eats like 2 bags of
Skittles.

And then he goes to practice and
he comes back and he has like

another latte.
And I was just thinking, what

the hell is the Seahawks staff
doing?

I don't understand how this he
still performing at a level like

that so.
So you know what, you hit on an

interesting point.
And so here's the other thing to

throw into this.
Number one, I'm not saying DK is

lying, but athletes do lie.
And a lot of times I, and I've

worked with athletes that have
that have done this on purpose,

They will actually lie about
what they're doing.

So their opponent thinks they're
doing something else or that

somebody else tries to do the
same thing and it just hangs

them.
But that's not what they're

doing at all.
It's hilarious.

Second thing, though, is I often
look at these things and you get

like these younger athletes or
just anybody inside, like Owens,

they say they only eat
McDonald's and they do all this.

And my thought is always, man,
how good could they be if they

didn't do that?
And so people look at us.

You don't have to do that stuff
because look how great they

still are.
And I look at it as, yeah, and

I've seen this with some
athletes over time where

absolute rock stars, especially
on.

And then later in their career,
they're playing by injuries.

And you look and you go, yeah,
because you were able to do a

lot based on that genetic
lottery early on that might only

last you for so long before
systems start to change.

And so how do you keep that car
running at its optimum?

You can only put crappy unleaded
gas in that Ferrari for so long

before it starts to backfire,
right?

And so it's I think it's an
issue of I always think that is

the slippery slope to go
downwards.

They look how good they did and
yet they only do this.

And my first thought always
turns to, and my God, how good

can they be if they didn't,
right?

That's just a scary thought in
some of those cases.

And then there's other times
where with certain athletes

you're like, man, I ain't going
to broke.

What's worth, I'm not going to
break.

If it's not broken, I'm not
going to fix it.

We'll just make a few little
tweaks.

But you also want something
they're comfortable with.

So you don't want to do this
complete overhaul and make them

hate the process because they're
so restricted on what they do.

You got to meet where they're
at.

Coming back to the assessment
and testing, do you ever use

OGTT as part of the assessment
for insulin or?

You can be done with athletes.
No, we haven't had the need to

be honest.
OK.

OK.
Because I'd be curious because I

think that the biggest thing you
highlighted you're it's the

response to meals is what we
really care about.

So do you find that the IGF 1A
single, is it IGF one or do you

only check on IGF 2 as well?
No, we only use IGF one, but we

use it in a chronic sense.
So looking at it's upstream from

the, the stimulus itself in
terms of, and it's the problem

with IGF one in circulation is
that you don't know whether it

is liver or muscle derived and
it can be both.

And the liver derived IGF one is
typically the one that's going

to be responsive to the growth
hormone stimulus.

IGF one.
And we also see this even with

BDNF because there's also muscle
Dr. BDNF where that IGF 1 is

coming from doesn't really get
distinguished in the

bloodstream.
But the overall IGF one

response, we have found some
pretty interesting correlations

with strength performance over
the course of a season and

changes in IGF one, especially
in female athletes.

And we've also found some pretty
profound responses in or

changes, I'm sorry, in response
to high training volume.

Yeah.
So let's shift to talk about

growth hormone actually in fact,
I remember you talking about

this is, I don't know, 2009 is
the class.

I was weird that I mean growth
hormone, pulsatile hormone, we

can't really measure it.
And so we actually check IGF for

that.
So can you, does it give you,

does it have a dual purpose in
that regard that you can also

check your chronic growth or
HOMO state for that?

Yeah.
And IGF 1 can be used to for

that.
But also, again, since we don't

know necessarily where it's
coming from and whether it was

GH influence, we'll typically
still measure GH.

The problem is if you miss the
pulse.

And so one of the things we try
to do is if we're looking at

growth hormone from a recovery
standpoint, we don't measure in

and around the training bout,
right?

Because that's that training
bout is going to have a pulse

Tau influence on the growth
hormone and that could influence

it.
So we try to control for time of

day and more of a chronic type
of measurement.

And like I said, it's been
interesting because I think

across, God, I don't even know
how many studies now, we rarely

see a chronic change in growth
hormone with the male athletes,

but we do in the female
athletes.

And actually resting levels of
growth hormone in the female

athletes that we've tested are
between like 4 and 8 fold higher

than the male athletes in most
cases.

And so they, part of that is
probably accounting for why they

aren't able to respond to
training with increased muscle

and things like that because
they don't have the same

testosterone influence that the
males do.

So there's a bit of a trade off
there there.

At least that's the speculation
that I think makes reasonable

sense when you look at how these
things correspond to the ability

to synthesize proteins and what
not.

But again, there's more to that.
There's a mechanical stressor

factor and all that other stuff.
But within the hormonal milieu,

the GH part is pretty
interesting.

But growth hormone also just
plays an important role in other

recovery factors too, in terms
of tissue remodeling and repair

in collagen synthesis and stuff
as well.

I don't want to dismiss it, and
I do think it's an important

hormone, but yes, it's acute
influences.

It's interesting growth hormone
responds well to stress, too.

So under stressful conditions,
we'll typically see growth

hormone go up and would seem
counterintuitive because like

that's certainly not going to be
an anabolic scenario.

But what growth hormone is doing
is it also is a fairly potent

lipolytic hormone.
And so it does help mobilize

fuel resources to potentially be
able to spare protein in that

case.
So there's interplay with that

and other hormones in that case.
Yeah.

I think most people when they
think of growth hormone, they're

thinking baseball, they're
thinking athletes using it for

recovery, primarily to to heal
back from injuries.

But I think people miss the
importance of what's your role

in metabolism kind of like.
Absolutely.

So from that lens, what else
should we be aware of?

And what I I started this
conversation by talking about

this individual who was talking
about the acute effects of

growth hormone to training.
Are there any strategies with

respect to our training that we
could deploy and modulate it to

our benefit?
Not really.

I think we've put too much
emphasis on that.

I think there is, I think there
is some value in understanding

the acute hormonal responses to
training, but realize they're

very short lived.
If they're doing anything,

they're serving as important
signals for these other

translocation factors and the
other things that go on with the

protein synthesis.
But acutely, so much of what we

see from exercise is more the
mechanical stimulus than even

the hormonal.
Not that the hormones don't

matter.
And especially chronically with

what we might see over time,
certainly we block growth

hormone, block testosterone.
That is not going to be a pretty

situation.
But ultimately basing your

entire, so here's the funny
things.

The lifts that tend to be the
things where we see this

increase in growth hormone also
happen to be the lifts that

would form the foundation for
most of your strength training

in the 1st place, or even
hypertrophy if you're looking at

bodybuilding and whatnot.
So it's not so much necessarily

that the growth hormone is
what's indicating that's why

it's effective.
It's that growth hormone

response to stress, right?
And you're applying this

relatively efficacious stressor.
It works to increase muscle, to

increase strength.
So we like dumb luck into it,

right?
So somebody could be like, hey,

if you look at these exercises
that primarily increase growth

hormone and you make those your
priority in your training,

you're going to get stronger.
And so no kidding, because it

turns out most of those are
squats and deadlifts, bench

presses to some degree, a lot of
whole body multi joint type of

movements.
Wow, genius, right?

So I think it's like twisting
the narrative a little bit.

And it's funny because the
pieces of information are

actually correct.
The why is not.

So it's yes, those are the
things that make growth hormone

go up and yes, those are what
make you stronger.

But it's not because of the
growth hormone that's happening,

but it's the growth hormone is a
signal for what that particular

exercise or exercises or
exercise about is really doing

to the system, if that's the
case.

So again, paying attention to
that, the pulsatile nature of it

when we may miss its measurement
and things like that, again, all

always important.
But that's not to dismiss the

role of growth hormone, right?
Growth hormone has important

physiological ramifications
within the human body, growth

hormone.
And This is why as we age, as

growth hormone declines, we see
these losses in muscle mass, we

see increases in body fat.
Is it all because of growth

hormone?
No 'cause there's other stuff

going on too.
But certainly that decrease in

growth hormones helping the
case.

And I think people also need to
be careful not to conflate

exogenous and endogenous growth
hormone.

So somebody taking growth
hormone versus the growth

hormone response to exercise are
not the same thing with

testosterone, right.
So people like, oh, people that

are taking testosterone, clearly
they have more muscle.

So testosterone doesn't matter.
Testosterone does matter.

But when you're taking these
high exogenous levels, it's

above and beyond what your
system would produce.

Yeah, you're going to be able to
support more muscle.

So we know testosterone can make
a difference there.

How much of a difference does it
make within an otherwise optimal

or normal range for, say, a
young, healthy male?

Probably not a ton, but again,
not knowing receptor

sensitivity, not knowing free
versus total, things like that.

Hard to interpret.
I I don't want to throw the baby

out with the bathwater, though.
I think there's some people that

have just bought into this whole
thing, researchers that are like

just completely dismissing
hormones as important in muscle

growth.
And I think that's missing it

too, because a lot of those
studies, they've measured the

hormones in responsible single
exercise bout.

They train them for 8 or 12
weeks and they go, oh, look, it

wasn't predictive of how much
muscle they gained.

I'm like, yeah, because every
workout's going to be a little

bit different.
I would be really curious what

that looks at, looks like when
you accumulate those effects,

because anybody that lifts on a
regular basis knows that not

every workout and every day are
equivalent, right?

There's some that are better
than others getting stronger.

And so I just, I think we've
maybe gone a little too far in

the, it doesn't.
I think one point we were like,

it matters so much.
That's the main driver and now

we've got to, it doesn't matter
at all.

It's all the mechanical stress.
I think the truth is somewhere

in the middle where the
mechanical is driving a lot of

it, especially early in a
training program.

But the hormonal response still
plays a role.

It's just not as big as we
probably thought it was.

What about lactate training,
though?

I remember reading a study way
back when, and this probably

when I was in college, about how
training above a lactate

threshold in our power aerobic
athletes, as you like to call

them specifically more than 10
minutes, had a significant

response greater than 24 hours.
In those instances.

It's not necessarily squats,
deadlifts, that kind of stuff.

Now we might be on a bike.
Right, it might be.

Recyclist that you've worked
with, any thoughts on that?

Lactate, lactate's a cool
molecule on a very, we could

probably put it in there with
cortisol and insulin.

In terms of being misunderstood,
we have a much better

understanding of it.
Lactate is not a bad thing.

Lactate itself is a fuel source
and the ability to metabolize

lactate, especially following
that workout to reconvert to

glucose to the Corey cycle and
things like that's a good thing.

And the ability to generate
lactate in that power or power

endurance athlete is actually an
adaptive advantage, right?

To be able to get to those
levels, to be able to go that

anaerobic, to generate that
level of lactate, but it's also

going to be heavily dietary
influenced.

But if you don't have a high,
high enough carbohydrate intake,

but you're not going to see as
much lactate accumulation,

things like that.
But I think what's important in

the lactate conversation is not
only production, but also

clearance in terms of how this
shows up.

But I think lactate does serve
an important biochemical signal

for the strain on the system.
It can cause these downstream

effects for mobilization and
signalling from from an effort

standpoint.
But yeah, more than anything, I

think understanding lactate as a
fuel source and understanding

lactate is an indicator of some
of the intensity factors can be

a super useful way of looking at
it.

Because I think for far too long
it's been looked at as a waste

product.
And I think too, I still hear

people really misunderstand it.
I've heard trainers tell their

clients like the reason you're
sore the next day is because of

lactate.
Typically they'll say lactic

acid, which is even more of a
problem.

But anyway.
But you're not sore because of

the lactate.
You might be sore because of the

workout that caused lactate to
increase.

And I'll put it this way, if
you're still sore from lactate

the next day, please get to an
endocrinologist because there's

something really wrong with you.
Lactate should not stay elevated

though.
Like lactate clearance usually

occurs within 5 to 15 minutes in
almost every study we've done.

Why might it increase growth
hormone response though in some

of those athletes I was talking
about?

Honestly, a lot of it's the
signal, it does appear that from

from an upstream standpoint in
terms of growth hormone

releasing hormone, because
lactate can also work at the

level of the brain, right?
The brain has this, the ability

to sense this.
So in many ways it's serving as

an indicator of intensity.
So I guess, well, lactate itself

has been, at least in some
animal studies, shown to

influence growth hormones
response.

Also realize that the same
training that produces A lactate

response tends to also be much
of what produces a growth

hormone response, right?
So it's a little bit of

everything in there.
And again, it's a challenge with

looking at any one thing in
isolation in the human body

because there's such complex
interplay.

And it's honestly one of the
things that drew me to the

endocrine system initially was I
loved how complex it was, but

also how redundant it was,
right?

There are checks and balances
and fail safes in place so that

we don't fall apart because of
one thing not working right.

Like it's amazing how good we
are at doing that.

But because of that, it's
important to be able to look at

those things together so that
we're not overly simplifying an

otherwise fairly complex
Organism to do this.

But I also don't think we need
over complicate it because I

think that it makes some of the
interpretation very difficult.

But it's also not, I don't know,
I guess in some ways we could do

like an endocrinology for
dummies kind of thing.

But at the same time, it's we
have to be careful the pathway

we go down with that because of
what some of the interpretations

might be.
And certainly the things that we

might see with exercise,
overreaching, overtreating,

whatever it is versus a true
disease state.

It's interesting because there
are some interesting parallels,

but very different
repercussions, right, and very

different long term implications
in terms of recoverability

versus a true dysfunction that
we might be looking at in that

case.
Amazing.

Sean, I'm looking at my notes
here and we're not even about

50% even talk about the sex
hormones or catecholamines and

just some of the future
directions of what preservation

of muscle that I want to talk
about.

But I if your game, I know man,
if your game, maybe we'll just

park it here and have you come
back for a Part 2 because I

think that people are gonna be
really upset if we don't talk

about the sex hormones.
Everybody wants to know about

testosterone.
Everybody wants to know about

that.
So let's do that.

Right now, if you want, you want
to talk about testosterone.

Let's do it, let's do it.
So let's briefly talk about the

sex hormones, right?
It's testosterone, estrogen,

progesterone you had mentioned
all very important, but I think

you highlighted estrogen is
really important in male

Physiology as well.
What should we understand about

these particular and also maybe
if we can focus on the role of

estrogen in males and then the
role of testosterone in females?

Because I think people don't
understand that they're

necessary in both.
Yeah.

And so I think when we first of
all three of those are steroid

hormones, right.
So again much like cortisol,

they come from cholesterol.
Cholesterol is the mother

steroid in this case.
So because of being steroid

hormones, their half lives also
different from peptide hormones.

Their rate of appearance is a
little slower, but they hang out

for a little bit longer.
They will use transport proteins

to move them through the system.
So this is where we start to

look at free versus bound
versions of this and with the

free being the more bio active.
But when we look at it overall,

especially taking testosterone,
so obviously it's an and it's an

androgen, it's an androgenic
hormone, right?

So it's responsible for a lot of
the masculinizing effects.

Women have testosterone as well,
just in much, much lower

circulating levels and much on
the women's side.

In the men, most of our
testosterone is derived from the

testes.
In women.

You can get a lot of that from
the adrenal gland, right?

So the adrenal cortex also
produces your androgens, your

mineralocorticoids and your
glucocorticoids.

And so in them that can be a
good source of this in terms of

what we see.
And in women, honestly,

especially in some of our soccer
studies, we saw a significant

increase in testosterone coming
out of preseason because of the

training volume, right?
So it is also responsive to the

need to handle this high level
of demand physiologically.

And so I think when we consider
how those things fit together,

they really do start to to mesh.
And in males, obviously look, we

hear often the importance of
testosterone in males and it is

right.
And it's also understanding

they're between physiological
and super physiological levels

is important in understanding
using testosterone versus the

testosterone you naturally
produce.

And I think we should pay
attention to this.

Now, is there some magic number
of what testosterone should be?

No, there are these normal
ranges.

Though I'll be honest, the more
and more I've worked with

athletes, if you're towards the
low end of normal function does

not seem to be nearly as good as
if we can move you up towards

the moderate to high end of
normal.

So even within normal range,
there are differences in this.

And I know some have argued this
that it doesn't really matter,

but I think those have been
poorly done studies that they're

relying on.
And it's also not looking at

outcomes that would be, let's
see, highly important to

athletes, for example, in terms
of where we see that sort of

optimization and strength and
overall performance.

So I think those factors are
pretty critical to look at.

But I think the other thing too
is estrogens.

So estrogen also tends to be
cardio protective.

So estrogen plays a pretty role
in cholesterol accumulation.

So if we're looking at
atherosclerosis, right, So

there's a protective function of
that.

And in males who use anabolic
steroids, especially anabolic

androgenic steroids, if they
suppress their estrogen too

much, especially if they're
taking an anti estrogen or an

anti aromatase and things like
that, that can bring estrogen

down to a level where that might
precipitate some of these

cardiovascular factors, right?
The ones that are less than

ideal under those circumstances.
And the other thing too is a

lack of estrogen in men can
actually kill sex drive too,

right?
So this is important for

factoring this.
So we don't want to just look at

what your testosterone levels
are, but what are also your

estrogen levels?
Because the flip side of that is

in a lot of males, if you take
anabolic steroids, your estrogen

levels can also be very high if
you get a lot of aromatization,

right?
So if you get a lot of

conversion because of the excess
testosterone.

So understanding that interplay
is very important for

understanding the overall
effects on the body as well.

But from an endogenous
standpoint, what we make right,

we know that these are
responsive, especially estrogen

or I'm sorry, especially
testosterone to certain like

high intensity types of
activities and stuff.

But again, just having this like
this little lit in testosterone,

in order to have a more chronic
effect of this, your basal

levels have to go up, not just
this one little one hour post

exercise magically creates all
this other muscle.

There's these other 23 hours to
account for, right?

So I think that it's an
important signal for some of the

other pathways that are involved
in protein synthesis.

But I don't think it is the big
dog.

We probably thought it was
acutely versus some of the

chronic effects, but acutely I
think the mechanical stressors

and some of the other factors
are probably significantly more

important for the adaptation of
that training.

But overall, I think that the
role that it plays and I think

that understanding the things
that can decrease testosterone

because we if we circle back to
what started this stress, right

when we're talking about
cortisol, stress can have

thrush, cortisol response or I'm
sorry, crush testosterone

response under high stress, we
start to see these testosterone

levels.
Full dietary influences can play

a pretty big role in
testosterone as well.

And so especially if you were
under fueled as a male athlete,

this is one of the things we
look for in our athletes.

As a matter of fact.
And there's been a couple

athletes we've worked with over
the years where the decline in

testosterone was really one of
our big indicators.

And once we finally started to
dig deeper into their fuelling

strategies and how many calories
they were eating or not, that

was where we were able to make a
pretty big difference.

And that rebound of testosterone
was really an important

indicator and their performance
also went along with it, right?

So we know it ties in from that
standpoint.

But again, I wouldn't put too
much emphasis on just the acute

effect.
If anything, what's interesting,

and we had a study in wrestlers
that looked at this, but the

acute effect of testosterone may
be more related to

aggressiveness in sporting
situations and also a higher

likelihood of winning.
But it's but the way it's

typically talked about in terms
of its influence on muscle

growth and things like that.
I got to be honest, it's

probably more of a drop in the
bucket acutely than what we see

for mobilization for wins and
losses in like combat sports and

grappling and things.
That's cool study.

But anyway, so I think overall,
looking at those sex hormones

and then on the female side,
that regulation of those sex

hormones and normal menstrual
variation over the cycle is

something we need to pay more
attention to.

And I think that female athletes
need to understand that not

having your period is actually
not a good thing, right?

Like we, we want normal
menstrual function as well as we

can define normal in that
capacity.

And so the roles of estrogen and
progesterone and that and their

normal fluctuations through the
cycle are something we need to

stress more.
But I think we'd probably put a

little bit too much emphasis,
not we, the collective we

doesn't apply here.
Certain social media influencers

have put a little too much
emphasis on using phases of the

menstrual cycle to guide your
diet and your training and

stuff.
We're not there.

And honestly, if it does have an
influence, it's fairly small.

And I think it still goes back
to the conversation we had about

that monitor.
How are you feeling kind of this

auto regulation, sensing
yourself?

Yeah, there's certain times
during that, that menstrual

cycle where you don't feel as
good or especially premenstrual

with cramping or other symptoms
that's going to impact your

performance.
It's not so much about the

hormones, it's about the
symptoms that might go with

that.
So I think we're in the early

stages of understanding more
about that.

And I think there's some great
researchers digging into this.

We've done a couple studies on
this as well.

But I think understanding these
hormones influence and the fact

that they're normal
physiological pattern is

important to preserve.
We want to make sure they are

operating normal, right, that
we're not getting these massive

fluctuations or dampening that
response.

And that applies to either the
female sex hormones or the male

sex hormones.
And I think that's the reality

too that's often lost in this.
I will say one thing that that I

think is particularly
interesting.

Testosterone plays an important
role, especially in fetal

development when we're looking
at some of the receptors that

basically dictate power response
later in life.

So even sex differences due to
testosterone receptor exposure

actually make a difference in
development there.

And it's why we start to see
some of these things show up

later through puberty when those
hormones start to increase.

There's more receptors available
in the male athlete in order to

do that and it can drive a lot
more from a performance

standpoint.
Yeah, I love it.

A couple things to follow up on
there.

And to your point about estrogen
and how critical it is for

cardio protective benefits of
bone health, that's another one,

right?
We can step to that in females,

but also in males.
I would say loss of muscle mass,

particularly with these
anorectic drugs is a bit of an

epidemic right now.
I agree.

So something to pay attention
to.

It's actually one of the
reasons, right?

So clomid clomiphene citrate
used to be something people

would have used to help,
particularly in somebody trying

to preserve fertility to
increase their levels of

testosterone.
But what we learn is that up to

40% of men completely destroys
their libido because it works

on, it's a selective estrogen
receptor modulator.

And so that's something
important to note, doesn't

happen to everybody, but can be
a drug that completely defeats

the purpose of trying to raise
those levels if that's a concern

for the individual.
And that's why you're starting

to see more people gravitate
back towards lower dose HCG, so

human chorionic and adatropin
because it does not have that

effect as someone intends to up
regulate the LH and FSH response

in that case.
Very expensive though.

Very.
Expensive and much more

difficult to get a hold.
Of and then to your point about

the dietary influences, I think
I remember recently come across

a study, Heinzelman, forget his
last name, fantastic.

He talked about like the the
recent study looked at a minimum

of 15% or maybe even 20% of
calories should be coming from

fat.
I think this is again, fat or

calorically dense.
And if you're really trying to

cut calories, if you're on a GL
P1 where you have no appetite

for fat and your your fat drops
below a certain level, like

that's again gonna have an
effect.

It could be one of the pieces of
the puzzle like we've talked

about.
This is all very complex.

A funny story I'll share with
you, Sean and I leave the

listeners with this exercise
Physiology class.

I remember.
So this is what, 2009, 2008

sometime at that point, I
remember a picture of you.

You put a picture of Mark
McGuire and you were talking

about Anderstein Dione and you
had the whole metabolism until

Anderstein Dione and you were
making the point about Mark

McGuire, about that.
And I just remember seeing

cholesterol upstream for that.
And I was like, yes.

And for the next, I don't know,
a couple of weeks, maybe even

months, I was just going home
and just smashing hard boiled

eggs, yolk included, but
especially the yolk just trying

to split.
And man, I just, I'm just

wondering what I did to my lipid
markers at that time.

But that's how stupid people can
be, and that's how stupid I was

at the age of, I guess, 19 years
old, just trying to.

Negatively influence you guys
that's.

How simple that is.
So thank you so much man.

Hopefully we'll find time to to
come back and talk about thyroid

hormones.
And like I said, I'm really

interested in talk.
I want to talk to you about

these myostatin inhibitors that
I think is going to be awesome

man.
Thank you so much.

You bet buddy, Good to see you
and yeah, happy to connect

again.
I think there's a lot more fun

stuff we can talk about, but
yeah, the GLP one and the

myostatin stuff is interesting.
Yeah, thanks for listening to

the other episode of Medicine
Redefined.

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