Why is my friend able to deliver higher Watts for a far lower heart rate than me?
And he mentioned, these are about 236 Watts at 116 beats per minute,
while I am averaging 160 beats per minute at the same wattage.
So the reason that I threw this in here is we get so many questions about
heart rate, like so many of them, and we don't address all of them just
because it's a, we've addressed it in a number of different capacities before.
Uh, but there's a ton of Nate.
Do you want to jump in on something with this?
I just
want to say, I know the answer to this to some of you will be like very
obvious, but because we get so many questions on this, we want him to answer
it and maybe two with what, what Chad says, you you'll learn something, but.
Not everyone who listens to the podcast has the same understanding of this.
And it's important to get this on record.
Absolutely.
Yeah.
Okay.
So I was banking on a little bit of recovery far along sent to another
deep dive, but your goal goes Eugene.
So I think to sum it up, your question is quite simply why doesn't
heart rate consistently correlate with power output and super short.
In your cases that your friends probably fitter than you, the problem is, is that
doesn't necessarily translate to faster.
Okay.
So, so the short answer, not the super short is that how your
heart rate relates to power?
Not only varies between writers, but it can even vary within the same writer.
And this can be explained by things like training adaptation.
Of course, it can be due to a number of temporary factors that affect
heart rate think sleep dehydration.
Caffeine ingestion blood donation can have an impact, fatigue level or
level of recovery call it whichever you like, but, but it's a long way.
So a number of things that impact heart rate might not impact
your ability to create power.
And it's for this very reason, that training strictly by power
poses, a number of challenges that you probably won't face.
If you couple heart rate with power data, and ideally you asked me you'll,
you'll lump RPE, or your rating of perceived exertion into that whole
picture and portray a much clearer picture of what's going on with your body.
You know, basically combine the objective with the subjective, but,
uh, that's, that's a little off topic.
What are some of the causes for all these differences and changes in heart rate.
And I, and I want to approach this question from the angle of the
cardio system are really systems.
So there's the cardio-respiratory and, uh, which is sometimes cardiopulmonary.
I honestly don't know if there's a difference and the cardiovascular system.
So really the heart, the lungs, the blood vessels, and of course
the actual blood in circulation.
And these can all explain one writer's heart rate being vastly different from
another's and also how your heart rate can change as you get fitter and faster.
So each of these components of your cardio system can undergo
training related changes, right?
We can achieve them in supplemental ways, like a altitude training or
heat training, that sort of thing.
But we're going to limit this discussion strictly to the more typical training.
So either riding indoors on your trainer or on rollers or riding outdoors
in your usual outdoor environment, so nothing out of the ordinary,
nothing like a training camp or an altitude camp or anything like that.
So through regular structured training, that progresses that are
productively challenging, right?
Rescue on a normal basis.
Um, you assess reassess your capabilities at normal intervals.
Uh, we can bring about all sorts of changes to the body.
And this includes more than just the muscles.
We're also seeing adaptive changes in the heart and the lungs and the blood vessels
and the blood is I referred to earlier.
So the three let's call them levels of adaptation that I see as having
arguably the greatest impact on her.
Are the size and strength of your left ventricle.
And this is one of the four chambers of the heart that pumps
oxygenated blood out to the body.
So out to the muscles in our context, secondly, is that hemoglobin and the
red blood cell content of our blood.
So basically just a couple of components of the blood that carry
oxygen to our aerobically inclined muscles, and finally the mitochondria.
So within each muscle cell where the oxygen is actually utilized.
Turnover energy or, or as I like to describe it, make break and remake ATP.
So all of these things we can influence with endurance
training, endurance training.
So if we take a really simplistic look at this, start with the left
ventricle, the heart can pump so much blood, and it's a matter of a couple
of the left ventricles capabilities.
First it's filling capacity.
Which has to do with its size.
And then it's injection fraction with kind of, has to do with the strength or
really how much of the blood inside it.
It can clear out with each contraction and that word right there, contraction.
It tells you we're dealing with muscle.
Yes.
Cardiac muscle in this case, but cardiac muscle can experience.
So similar, in some ways to how skeletal muscle can increase cross-sectional
area of each muscle fiber, but in cardiac tissue, it's more about
enlargement of the compartment and then thickening of the actual cardiac wall.
So again, kind of a size and strength sort of, sort of deal.
So now every time your heart beats pushes out blood and how much depends
on, on these two things and that's referred to your stroke volume,
and then when you simply multiply.
Stroke volume times, beats per minute, you get your cardiac output.
And this is simply the total amount of blood.
You push into circulation over a minutes time.
And if you can push more blood, your heart, doesn't have to beat as many times
for a minute to do the same amount of work or generate the same amount of Watts
as someone with lower cardiac output, you know, a weaker or a smaller left
ventricular, a lower ejection fraction.
So quick recap at this point is, is that, that the bigger the heart chamber has.
Or the bigger the heart chamber is there's more room to stock up on
oxygenated blood, and the more strength to pump that blood out to the muscles.
This requires less heartbeats per minute.
As you become fitter.
This is going to be a recurring theme.
So next up is a hemoglobin and the red blood cells.
So we're talking about the blood itself.
Now with more hemoglobin, we can bind more oxygen and that means
greater delivery capacity to the muscle with more red blood cells.
This, this also means greater oh.
To delivery to our working muscles.
And then when you combine the two more hemoglobin in more red blood cells,
It's pretty easy to see how we're basically setting the stage for greater
and greater aerobic work capacity.
Also, it's becoming pretty clear how the heart can beat fewer times while still
delivering big quantities of oxygen and in doing so lowering heart rate at
that same power output, the very same power output that used to require more
heartbeats because the blood just wasn't bringing as much oxygen as it is now.
So to recap that.
A combination of changes to your blood, both brought about via endurance
training means more oxygen gets pushed to the muscle and also means less
heartbeats are required per minute.
As you get.
And then finally look at the mitochondria and it's worth mentioning that there
are a whole lot of ways, a lot of factors and adaptations we could look
out, but I've limited this particular list to just these three heavy hitters.
So once all this blood think left ventricle and the oxygen, it carries
the hemoglobin and red blood cells.
It makes it to the muscles.
It has to be picked up and utilize.
And here to so many things taken place, but we'll just, we're just going to
skip to where the oxygen actually reaches the inside of each muscle cell.
So all this, all this aerobic supply, all this oxygen is now reliant on both
the quantity and the function or the quality really of your mitochondria.
And it's not enough just to have a bunch of, you know, basically
weak sauce, mitochondria.
It's not enough to have a handful of really robust ones, either.
We need many and we need them some function really well.
We need them to be here.
And this also is a result of proper training and adequate recovery.
Uh, a huge part of which is, is your diet, but that's a whole other
enormous discussion, but it can influence all of this suffice it to
say effective endurance training brings about more mitochondria that suck up
all this freshly delivered oxygen.
Meaning less oxygen will make the round trip back to the heart
because you're utilizing more of it.
And so once again, your heart doesn't have to beat as many times as it
used to when you were less than.
So final recap, this, this an elevated level of fitness.
So via endurance training and in our context can lead to
greater mitochondrial density.
That's the term you're going to see quite a lot.
If you read really anything related to endurance training within your muscle
fibers and this translates to better use of the oxygen, it receives meaning once
more heart has to be fewer times each minute as your endurance capabilities.
So I'll, I'll wrap that up super quick.
It's it's, it's just, uh, just that three of the many, many possible training
adaptations that can explain how heart rates differ across and within endurance
athletes are these three things.
There are others, and these don't even take into account the wide range of
differences in heart rates, totally apart from endurance training, having
nothing to do with being right.
So I'm gonna
summarize, as you get more fit, generally at the same wattage, you will have a
lower heart rate, but two when comparing between different two different people.
PR nothing.
Um, because it doesn't, it's like comparing the, the, the
revs in a car for like overall what car is going to be faster.
You can have totally different engines.
And if you look at our group ramp test, this is a great example,
especially the last test.
Maybe not for two desks ago, Pete and I are pretty similar in power
output, but our heart rates wildly different people are just commenting
on how low Pete's, uh, heart rate is relative to his power output.
Um, and Lance Armstrong famously had a very high power.
Output, um, and you just can't get speed from power or, or fitness, but
relative to yourself, if you raise your FTP by a hundred Watts, man, your
power at that previous FTP is going to have a much lower heart rate than
what it does now at your new FTP.
Oh, yeah, absolutely.
Uh, Amber is going to be joining us again here in just a bit.
So one way to look at that is that heart rate is one indicator of
something that's going on in the body.
However, it is not an indicator of like performance, right?
Chad, it's not an indicator of fitness or anything else.
You can see trends over time and individually check it
out, but it's absolutely.
Yep.
And that's like a hard thing too, even with trends like Nate, I'm sure.
In this whole process of you discovering your limits and going through that
whole thing, I'm sure you've seen heart rate trends and some days it's been
up some days it's probably been down and some days it's kind of changed.
It's really tough to just kind of put a lot of stock
into whatever that data means.
Right?
Yeah.
The biggest correlation I, I find for performance is just how we.
Like, I feel I kind of like the day, or once you get into your workout, I pretty
much know how well it's going to go.
And sometimes my heart rate is higher than normal.
Sometimes it's lower than normal, but if, you know, if you feel horrible, it's
usually going to be a horrible person.
Not all the
time, but usually,
yeah.
Chad, what?
You were going
to say something.
No, no.
That's I was just agreeing with Nate's point.
I think in all cases, I mean, data is useful in so many ways, but it just
always boils back down to how you feel.
It's like a, sorry, go ahead.
No, go ahead.
I was going to
change subjects.
I was going to say being a fan of motocross racing, it's always
extremely frustrating because that sport isn't data-driven, it doesn't
really have any way to like measure performance necessarily other than
you are faster than the other person.
So I don't blame them for using heart rate, but.
Uh, they rely on heart rates so much, and we're pretty spoiled having power
because then we can actually see what a person's doing compared to their
weight and see so many different things and get some actual, you know,
objective data about what they're doing.
Uh, so many times I'm watching it and somebody is like, oh, I
bet his heart rates at one 90.
Or like they've even had heart rate data.
And they're like that person's at one 90 and that person's at one 60, the person
at one 90 must be trying so much harder.
And it's not the case.
This happens in the tour de France too, right.
Or the power that they stream is like one second power.
And you'll see, it'll be like 500, 200, 100, 500.
And you're like, what's going on here?
Crazy.
It's pointless.
Yeah.
You're not getting much insight from it.
Right.
And that's so, yeah, it's um, it's definitely something to keep an eye on.
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