Name: Does A Lower Heart Rate Mean You're Fitter? | GTN Does Science
Uploaded: 2021-08-29T11:41:38.000Z
Duration: 13 min 6 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

程度の副詞

Fraser Cartmell: Here's a question for you, do  you monitor your resting heart rate or indeed  

pay attention to what your heart rate is doing  whilst you're training, in general? If you do,  

様態の副詞

then are you feeling fitter if you start to see  those numbers drop over time, and especially when  

you're competing for sessions with each other? Or  perhaps you pay attention to what your training  

buddies or your friends are doing and you  find yourselves competing amongst yourselves.  

Should you? Does this even matter at all? Well, to answer a few of these issues and  

delve into the complexities of heart rate in  a little bit more detail, I reached out to  

a pair of experts who are going to talk to me  about what it means to have a lower heart rate,  

how this might indicate levels of fitness and  what other factors could influence this too.  

[music] In this modern age of social media and ready  

access to online content it's remarkably easy to  follow along with what the pro-athletes are doing,  

especially when some of them are so transparent  with sharing with us their online training data  

via their social media platforms. Now,  one such athlete who is particularly  

happy to lay bear the nuts and bolts of  his training routine is multiple Ironman  

and Ironman 70.3 champion, Lionel Sanders. Now in the context of this video, that's  

particularly useful because those of you who pay  attention close enough will perhaps notice that  

Lionel has what appears to be an incredibly low  heart rate during all these incredible training  

sessions that he is churning out on the bike and  run. I thought I would get in touch with Lionel's  

coach, David Tilbury-Davis to try and delve  into this subject in a little bit more detail,  

Now, David has been coaching athletes  of all abilities for over 20 years now.  

He's also lectured in anatomy and physiology  too, added on top of his first-hand experience  

of coaching an athlete of Lionel's caliber. I was  keen to hear his viewpoint on what it might mean  

I started by asking David if he could explain  the physiology of the heart a little bit  

and highlight the variances from person to  person, and also perhaps why somebody like  

Lionel would have such a low heart rate value. David Tilbury-Davis: First of all, there's the  

transportation of oxygen through the lungs into  the bloodstream, and clearly, the more that you  

can do that the more talented you are likely  to be as an athlete. That's why you hear of  

these very high oxygen kinetics numbers for Kenyan  Marathon runners. Now, once that oxygen is in the  

bloodstream you've then got your red blood cell  count which is carrying about 98% of the oxygen  

that gets absorbed, other 2% ends up in the plasma  volume. That oxygen then, gets pumped through the  

heart and then moved to where it's needed. In terms of the actual heart,  

you've got the size of the heart which is a key  factor. You've got gender differences. Typically,  

pound for pound, similar, weight male, female,  height et cetera. The female will still have a  

physically smaller heart. Then obviously, you've  got a broad spectrum of differences between  

individuals. You might have somebody that has a  very large heart and somebody that has average,  

and somebody that has quite small. In my own personal experience,  

I can give you an example where I was working  with an amateur athlete who was in her 30s  

on a training camp with us. We were out for a  run and she was explaining that her personal  

trainer had said her maximum heart rate was 220  minus her age. She was in her early 30s, and  

she was running along, chatting away to me like  we're talking now and her heart rate was 192.  

I explained to her, "Well, actually, genetically,  you probably just have a very small heart and  

consequently, you have a very high heart  rate to achieve a certain rate of blood flow  

or cardiac output because cardiac output is  simply stroke volume times your heart rate."  

Going right back to then somebody like Lionel,  then you have an individual here who clearly,  

in my mind, has a very large heart, not  in a medically risky way, because there  

are things like cardiac hypertrophy which  unfortunately happens in some athletes.  

One aspect of training as an athlete is you  get what's called athlete's heart, and this  

is the most prominent part of that athlete's  heart, is an enlargement of the left ventricle.  

That enlargement creates an increase in  stroke volume, which increases the delivery of  

oxygen to the muscles, so that's a byproduct of  endurance training. You couple that with somebody  

that naturally has a large heart, you're  going to have a very low resting heart rate  

but you're also going to have a ceiling on  the maximum heart rate because there's only  

so much oxygen you can transport going back  to that, what you can absorb, limitation.  

That's why in individuals like  Lionel, whilst you might see  

that when they're riding moderately hard,  heart rates of 120 in his early 30s,  

you're also not going to see a  maximum heart rate of 180, 190.  

Fraser: Given David's example of the female  athlete with a higher heart rate, I asked him if  

this is a good way perhaps of proving that athlete  to athlete comparisons aren't helpful, given she  

could perhaps have been running alongside another  friend perhaps with a significantly lower heart  

rate, which of course is entirely possible. David: In the same way that there might be height  

differences or leg length differences or muscle  mass differences, or fiber type differences,  

there's also minor difference in cardiac  morphology, I guess is maybe the right word.  

In that scenario, I would say that  you're really best comparing heart rate  

reserve which is the difference between your  resting heart rate and your maximum heart rate,  

and then whatever you're at as a  percentage of that heart rate reserve  

is probably the best comparable  comparison between individuals.  

Fraser: In addition to this notion of a wider  heart rate range, he also explained what might be  

an indicator of improved fitness and  he used swimming as a case in point.  

David: As you get fitter typically, you see  resting heart rate lower. In some instances,  

you either see an increase in maximum heart  rate or you're at least see a stabilization  

of it and you might say, "Hang on a  minute. Why would I see an increase  

in maximum heart rate?" Well, a good example is  swimming. Swimming is very technically driven.  

If you're an adult onset swimmer, when you start  out, your mechanical efficiency in the water is  

really quite low comparative to Alistair or  Jonny Brownlee. Your capacity to express  

force against the water is not limited by your  actual central cardiac output, it's limited by  

your muscle recruitment and muscle usage. As you improve in technique and you improve  

the ability to apply force to the water,  you're going to be placing a larger demand  

on the heart, so the maximum heart rate  may increase in the swim. That's a simple  

example of explaining why it might increase. Fraser: The crux of this is that we're talking  

about apples and pears. Lake simply isn't being  compared with lake. Because of all the variables  

at play, it just isn't helpful to form an  opinion on our level of fitness because of  

what our heart rate is doing compared to others. David: The simplest analogy I've always used with  

all these things is, if you imagine that one  is like a car then your speedometer is the  

power meter, is the pace that you're running  out with your Garmin or the pace in the pool.  

That's your speedometer. 50 kilometers an hour  is 50 kilometers an hour is 50 kilometers an  

hour. Your RPMs is your heart rate. Clearly,  for a 50 kilometers an hour you can have quite  

a variance in RPM depending on the environment  that you're driving in, all sorts of factors.  

Then your fuel economy is your RPE, and again,  that can be influenced by various factors.  

When you look at that triumvir as an athlete and  you use that as your decision-making mechanism  

not favoring one or other part, but  actually looking at those three things  

if you have those three things, that  allows you to make the best decisions.  

[music] Fraser: Another viewpoint that I thought would  

be interesting would be that of a physiologist  who tests and sees athletes of all abilities on  

a regular basis in the laboratory environment. I  got in touch with Jonathan Robinson here at the  

university at Bath and asked him if it was fair  to say that individual variation is inevitable  

and how he sees that unfolding in the lab. Jonathan Robinson: I get a lot of people,  

recreational age group and even more  elite triathletes and cyclists saying,  

"My heart rate is much higher or much lower  than my friend's or my training partner's."  

We do a lot of physiological tests to create  their own personal training zones based on that.  