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

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  

to have a lower heart rate. [music]  

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.  

You can see people performing at similar levels  with similar say, VO 2 max scores or similar  

lactate turn points and things like  that. Their heart rates are quite  

different because they've got different ranges  I suppose. Like we've alluded to, it's always  

really important to look at what that heart rate  range is, where it sits at resting, where it sits  

when you're exercising very gently, and then how  quickly it goes up, and how high it goes up. Some  

people could have a really low resting heart  rate, but it only goes to 150, where someone  

could have a little bit higher, and they can get  up to 215. You've got those differences really.  

Fraser: I was keen to ask him about other factors  that might impact your heart rate and hear how  

they might create a lowering of the heart rate. Jonathan: Commonly, it's perceived that obviously  

when you go from having done very little, for  example, as you start to do more endurance  

training, that is going to improve the strength  of the heart, and the heart can therefore pump  

more effectively and more efficiently and pump  more blood round for each beat, and therefore  

that could reduce it. That thing is probably going  to be more in a novice athlete or new athlete or  

someone taking up the sport more recently. Altitude training is a good example in that's  

been shown to increase blood volume and plasma  volume, and the same with heat training,  

so that you've got more red blood cells, so you've  got more blood and more oxygen-carrying capacity,  

so possibly the heart doesn't need to beat  quite as quickly to supply the same amount of  

oxygen to the body for the same workload. Fraser: It was clear from what Jonathan  

was explaining that heart rate in itself  shouldn't be looked at in isolation, but  

I was keen to hear from him what things  we could do to monitor it and perhaps  

what we could use as an early warning system. Jonathan: I like the age-old monitoring waking  

heart rate. If people do that or resting heart  rate, you need to get a baseline. You need to know  

that generally your heart rate is say 60 beats  a minute when you wake or something like that,  

and then if you see one day it's 75, then  you think, "Hey, that's unusual." Whereas if  

you haven't got a baseline and you do it one  day and it's 60, and the next day it's 75,  

you don't know what's the unusual factor really. Fraser: Now, I really enjoyed speaking to both  

David and Jonathan. They helped simplify what  is a complex topic and put some things into  

perspective for me about it. I won't lie,  when I was an athlete, there was plenty of  

times when I would compare my heart rate to  others and think, "Are they fitter than me?"  

Clearly, as we've heard, that isn't the  case, and we shouldn't be doing that.  

What about you guys? Please let me know  how you monitor your levels of fitness and  

if you do that based on your heart rate. I  hope you've enjoyed this video and you've  

learned something from it, so please hit that  thumb-up, like button if that's the case.  

To get all the other content on the  channel, don't forget to subscribe  

and hit the globe. [00:13:06] [END OF AUDIO]