Hello, my name is Brandon Yates.
I’m a PhD student at Indiana University School of Medicine.
And I study the greatest medication of all,
and that is exercise.
It’s the only medication that’s available to anybody.
You can do it in the comfort of your home.
You can do it while you’re on vacation.
You can even take exercise “snacks” during meetings.
And that is what I’m here to talk to you about today,
about the great “exercise is medicine”.
So, when I got into research,
my initial passion was exercise to maximize performance.
I wanted to teach young athletes, old athletes…
basically, how to maintain movement
to compete at their event,
whether that be track and field, basketball,
football, soccer, whatever — you name it.
But there came a time during my master’s program
that I had the opportunity to become a research coordinator
at the Geriatric Research Education Clinical Center of the VA.
During my first — first — subject visit
I ran into a nice young man.
He kind of reminds me of my grandpa.
And so, as we began to walk up to the assessments…
if you ever walked with older adults or engaged with them,
you know that they tend to have a lot of stories.
They’ve lived a lot of life.
And on this particular day,
he began to tell me how
he lived just across the street from the hospital,
but he wanted or needed a family member
to drive him to the hospital.
So I asked him why,
and he explained to me about the one time
he had to cross the street
and he feared that he wasn’t going to make it.
And as a scientist,
and as a performance specialist,
I began to think, like, what is so troubling about crossing the street?
And as I began to picture it, I saw something.
Like, you have to cross the street
while cars are honking at you,
while there’s a lot of noise,
and then they do this thing where they have a timer
right across from you
that tells you you have 9 seconds, 8 seconds, 7 seconds
to get across the street before the light turns green.
And I began to understand how for an older adult
that could be daunting.
I mean, it’s almost like going to the Olympics.
I mean, if i see 6, 7, 8,
I think, okay, maybe I need to jog, maybe I need to run.
But for an older adult, that’s a challenge,
because they might not have the physiological resources
to be able to increase their pace
as they cross the street.
And so, that sense of not being independent
sometimes makes them become sedentary.
So, at that point, that is when my research interests changed,
and I began to focus on exercise to maximize longevity,
because I wanted to see,
how can we treat older adults just as we do athletes,
to help them to live a longer life,
to be able to cross that street with ease,
to be able to go to the local grocery store without any problems?
And so, I began to dig into research,
and yes, we have master athletes —
you know, those older individuals that still run
and have run all their life.
But then we also have the subject on the right,
who I saw, who was mobility impaired,
had a cane,
and for the most part struggled to move.
So, as I began to dig into the literature,
obviously muscles work,
but for older adults there’s another connection.
And that connection is the muscle-brain connection,
and that becomes important because we know, from data here,
as you can see…
is that over time, as you increase in age,
you increase your risk of Alzheimer’s disease,
which is one of the deadliest brain diseases
an older adult can have.
So, as you see here, on the x-axis
the years go up by 10s, all the way up to 2050,
and the color codes are broken up by 65 at the bottom,
starting at 75 in the yellow,
and starting at 85 in the purple.
And you see that as years go up,
it’s expected that the prevalence of Alzheimer’s disease
is going to increase.
And one of the potential mechanisms
is believed to be that our brains are shrinking,
and we have this extreme shrinkage in our cerebral cortex,
severely enlarged ventricles,
extreme shrinkage of the hippocampus,
in comparison to what we would expect
a younger adult or normal brain to have.
And this is supported by longitudinal data —
that’s shown here.
As we see on the x-axis, as age increases up to 85,
we can see that, from the y-axis,
there’s a nice decline in brain volume over time.
And that is directly correlated with the prevalence of Alzheimer’s disease,
as we see in the beginning.
But exercise — the greatest medication —
is not only good for our muscles;
it is great for our brains.
And that becomes more important as we age.
However, I was shocked to find in the literature
that although they talked about exercise
being great for the brain, that was it.
And when I think of medications,
there should be a dosage, a frequency,
ways to maximize it.
So, I became curious about something else that I know
can shrink the brain,
and that is hydration — shocking, right?
The water that is in our body…
how well can we consume and replace the water
that is excreted through our kidneys?
And there’s nice data here
that also shows that as there’s a change in body mass on the x-axis,
you can see that there’s a change in the lateral ventricle.
And that’s shown very nicely… this is…
as participants were dehydrated acutely
— so, within one day —
we see these drastic changes in brain volume.
So, we have these two factors, being hydration,
which could be acutely altered,
and then this non-modifiable factor, which is age,
that both come together at brain atrophy,
one acutely, possibly,
and one that might occur chronically.
So, what I wanted to see is,
how does exercise essentially become impacted by this?
My primary research question was,
does age or hydration
influence the benefits of exercise on the brain?
And we’ve seen plenty of literature that shows…
essentially, in younger adults,
drink your Gatorades before you exercise,
because we know we sweat,
and we know that we can improve performance,
but on the other end, we don’t have any recommendations
for older adults to drink,
but it’s all focused on the athletes.
So, tying my backgrounds together,
I wanted to look at this in the field.
I didn’t want to do it in a controlled laboratory setting
because who exercises
at 60% of their maximum heart rate
with no music, no social engagement —
that’s just not real life for a lot of people,
especially for older adults.
So, I went out to Texas,
to the Hotter’N Hell 100-mile cycling event.
And we recruited participants that were 18-70.
Now, you would imagine,
if you’re competing regularly in 100-mile cycling events,
you’re pretty fit,
so these are physically active adults.
And then for data analysis,
we broke them into groups,
essentially starting at 20, being young;
40, being middle age;
and then 55 and up… we considered that older.
Now, to answer the hydration question,
we looked at urine samples.
We had those collected pre and post,
and we analyzed that for two indices
that I’ll explain later called urine color
and urine specific gravity.
And then, to measure cognition in the field,
we chose a pencil and paper mental test,
and it’s called the trail making test.
It essentially measures two domains of executive function,
those being attention and your ability to task switch or multitask,
and I’ll explain those in detail later as well.
And then, of course,
we had to care about performance.
Because I was curious —
like, how fast are these individuals competing in this event?
So, for urine analysis…
again, because we’re in the field…
so we chose two very simple reliable tests,
one being urine color,
and that’s pretty much a yes-no observation,
where we say, is your urine dark?
Then you’re possibly dehydrated.
Is it light or pale?
Then you’re likely to be euhydrated, or well hydrated.
And then another measure of concentration
that’s a bit more objective is urine specific gravity,
and that is essentially a measurement of
how much fluid was in your urine
in comparison to how much
of the natural body byproducts were excreted.
And then, my favorite, the mental tasks we chose.
As you can see from part A,
here on the left,
participants had random circles on a page with numbers in them,
and they had to connect them in numerical order.
So, they had to find the 1, 2, 3, 4, 5, and so forth.
And that was the attention task.
And then we challenged them a bit harder with trail making B,
or part B tests,
and we had them alternate between numbers and the alphabet.
And so, you had to go from 1 to A to 2 to B, 3 to C,
and so forth.
Now, you can imagine, before you begin exercise,
this should be a breeze.
But after exercise — 100 miles —
we were curious to know how well these individuals had done.
Based on prior research,
we know that an acute exercise bout should improve cognition,
so we explored it here.
So, our results were…
when we looked at performance,
shockingly, the whole group took about 373 minutes
or approximately 6 hours.
Initially, we thought our younger adults…
although we only had a few subjects,
we thought they were just going to blow past the event,
but they actually did worse.
They took about 397 minutes,
whereas our middle age and older adults
took about 360.
And so, what you can see here is on the x-axis
we have the pre and the post measurements.
And what we ran was a paired t-test to look at pre versus post.
We basically combined test A and test B,
the total time,
into an A+B measurement.
And what we saw was that after a 100-mile cycling event,
the whole cohort became faster.
And as we look at the individual data here
— again, the open circles are the pre measurements
and then the closed circles are the post measurements —
you can see that there was one subject
that got a lot slower,
and for the most part everybody
tended to become faster after exercise.
And so, one of our hypotheses
was that the older adults were going to be slower.
And our data supported here… with that.
We see that the young group…
again, that’s 20-40
— the middle age — that’s 40 to 55 —
and then the older adults — 55 and up —
we see that their pre measure, which is that open circle…
they were a lot slower than the younger adults.
And then we see that, even after the event,
they remained slower.
So, we have a group effect, here, that was significant,
but no interaction effect.
And then, with these violin plots,
we decided to look at, does the magnitude change?
That means do younger adults
improve more after exercise
or do older adults improve more exercise?
And shockingly, they were all the same.
There was no difference in the magnitude of improvement,
meaning that if you were the slowest person or the quickest person,
on average, they took about the same amount of time.
But I also want to draw your attention here to the y-axis.
As you can see, the 0 in the middle shows no change,
meaning that if you got 39 seconds on one task before,
you got 39 seconds after.
That becomes even more interesting, though,
because we do have a substantial amount of participants, as you can see here,
that saw no change,
but to think about the ability to preserve cognition
even after a 100-mile cycling event,
or a 6-hour bout of exercise, is fascinating.
Again, within the whole sample,
very few got slower, which is a positive number;
most people got faster, as you can see here,
and that’s shown by the negative numbers.
So, the hydration question…
okay, we know that the whole group improved,
but there’s a lot of variability within the groups.
So, did hydration have a benefit?
So, we condensed the groups down to just middle age and older adults,
and then we separated them based off their hydration status.
So, again, remember, urine color…
did they have a dark urine?
We put them in the dehydrated group.
Did they have a high urine osmolality
— dehydration group —
before exercise?
What we show here is… as you can see from the x-axis,
we have euhydrated or well hydrated
versus dehydrated, so loss of water during exercise.
And we see that those individuals
who were euhydrated prior to exercise…
they saw a greater improvement in their cognition over time.
And looking at the dehydrated individuals,
they pretty much stayed the same,
which again, is still remarkable,
because they didn’t get slower —
they pretty much maintained.
But is that good over time?
We don’t know, and future research is needed.
So, one of the conclusions we came to
is that if exercise is great medication,
as we know it to be,
there’s vital information that is missing
on how the potency can be enhanced.
As you can think about it,
any drug in your cabinet will have this label on the back,
and it will say very pertinent information,
such as “when using this product, drink with water”,
or “take with food”, or “avoid alcohol”.
And it also has even more detailed information
as to if you’re younger than 12,
if you’re 6-12,
if you’re greater than the age of 18,
this is how you should take it.
And it’s important that this exercise medication that we have,
especially in the absence of an identified pharmaceutical drug…
we must maximize the potency.
So, future directions…
what is the mechanism?
Obviously, we know, okay,
there’s a potential mechanism that you can have
age shrinking the brain,
but is there a synergistic or additive effect with hydration status?
Because we know that older adults are more prone to be dehydrated
for several reasons.
Their kidneys lose the power to concentrate the urine,
but then, also, older adults tend to go to the restroom frequently when they drink,
so they have this behavioral factor
where they intentionally don’t drink enough
so that they don’t have to go to the restroom frequently.
So, how could those mechanisms…
or what mechanism might underlie
the brain atrophy combination
or either of those behavioral factors?
But another point to note here, that we did,
is our study basically advanced the field
because we did not study participants in a controlled environment.
We allowed them to have their natural human behaviors,
as they would exercise.
And this is important because we know that
with T1- and T2-type research…
those research protocols are pretty much controlled.
And in order to advance the field,
we must transition to T3 and T4 research,
which essentially looks at how the medication
is used in the community.
And our data here supports that older adults
who exercise can see a benefit,
but more importantly,
if they start exercise hydrated,
that benefit might be maximized.
So, future research is needed into this,
but nonetheless,
we should all drink our water and exercise as much as possible.
Thank you.