字幕列表 影片播放 列印英文字幕 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, 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. 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B1 中級 美國腔 心跳(Does A Lower Heart Rate Mean You're Fitter? | GTN Does Science) 9 1 joey joey 發佈於 2021 年 08 月 29 日 更多分享 分享 收藏 回報 影片單字