Heart rate zones training vs racing

Hi all, I’m hoping someone can help me with this question.
I’m a dedicated runner that has been moving over to triathlon training recently so even though my questions are running related I do train on the bike so they are relevant to all endurance sport. I use heart rate zones for my run training due to living in a hilly area. Ive started to wear my heart rate monitor to races mostly jyst to get the effort feedback after completing. Recently I ran a half marathon at an average heart rate of 173bpm for the 75 minutes I was running. This equates to 96% of my max heart rate. I ram a marathon yesterday with an average heart rate of 173bpm for the 2hr45 it took to finish so roughly 94% of my max heart rate over the duration. During both races I knew I was working hard but also knew by feeling that it would be sustainable probably. If I’d have followed onlime advice for heart rate zones then I would have to decrease my pace during both events to fall within the recommended ranges. My max heart is correct within a few beats I’m sure as I’ve done some tough hill sessions and bike workouts that have never seen values higher than 181bpm. My heart rate monitor is accurate (I think) as its a top polar one that is know to be one of the most accurate available. So my question is this, what type of athlete am I? Why can I work at such a high percentage of my max heart rate and should I be able too? There are many different articles suggesting the ranges for heart rates at different distances and I seem to fall out of all the rangess. I’m interested because obviously if I had have slowed down to suit my suggested zones I wouldn’t perform as good. I don’t appear to be very speedy in any of my training but seem to be able to suffer for a while. I’m starting ironman training following a brief rest so was hoping that you could help with my questions to give me a better understanding of the type of athlete I am and could become? Ps garmin race predictor doesn’t marry up worth my results and it’s estimated threshold is about my marathon pace which is again not really possible?

Of course, if you are worried, you should speak to a cardiologist, preferably one who has experience with athletes.

Tthere is a lot of natural variability. My heart rate while cycling is quite a bit lower, when I am fit it stays at 160ish bpm and my max heart rate is 178 bpm, perhaps lower. The second thing is that you should not compare heart rates for similar efforts but different types of activities like running vs. cycling. Some people have a lower threshold heart rate (or max heart rate), for others it is higher. However, you seem to have a lot of experience pacing yourself and in that instance I would always put more faith in your subjective pacing than what a fitness watch tells you based on statistical averages. I don’t think you can spend 2:45 beyond your threshold (very impressive time, by the way).

But let me ask you: if someone gave you the answer, what would you want to do with it?

The only conclusion I’d draw from that is to not use your heart rate to pace yourself — off the bike and on the bike. (Cyclists use power rather than heart rate for training as their primary metric anyway.)

In short, heart rate zones are highly individual and there’s probably not any grand design at work here- what’s important is not how it compares to others, it’s how well it compares to your own normal.

Most likely just extra adrenaline/nerves (and potentially extra caffeine.) You might also find it varies somewhat day-to-day depending on external conditions, diet, etc and some devices can be pretty prone to outliers, so I wouldn’t take too much from one individual session provided not experiencing any other causes for concern (dizziness, excessive fatigue etc.)

RPE is your limiting factor when it comes to a race and should ultimately dictate your effort- you’re trying to run as hard as you can, metrics such as HR and pace are just secondary measures of that. You should also have a general idea of what you’re capable of from training at race pace, and to a lesser extent, your performance during key sessions in general.


Dehydration plays funny things with your HR sometimes pushing it into a higher zone and I think air cooling helps you maintain it. Whereas inside you are (at least I am compared to 25mile TT with no bottle) and the heat won’t allow you sustain the high HR. Interval training often doesn’t push HR up as much as a continuous out doors effort anyway. My average HR if often a bit higher outdoors than indoors.

I don’t know about garmin’s running FTP prediction but I turned off the cycling one it wasn’t accurate enough for me to train off. It might’ve been based on all rides or a lot of rides where I wasn’t pushing to the limit and seemed to be below what I was comfortably (well relatively :wink: ) putting out for TTs.


Your running heart rate max will (most probably) be higher than your cycling heart rate max. I never see my max HR on “tough hill sections”. I need to do multiple sprints, or do repeated consecutive attacks, followed by a sprint to get there.
If you’re interested in heart rate zones, it’s probably better to find your threshold HR, on get your zones off that.
Additionally: everything other’s said about other factors that influence your heart rate. I’ve done long threshold efforts at 170bpm and at 160bpm, it varies with heat, hydration, caffeine, training load the days before the effort, and lots of other factors.


I usually don’t take max HR too seriously. I rarely see anyone actually report an accurate max. Maybe the max they have seen, but not the max. Only time I have actually seen my max was when I pushed to the point I started to black out.

I don’t think blacking out to find your max HR is a wise idea.

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Assume that I know my max heart rate within a few beats at least. Both of these runs were at an effort level that I thought I could maintain based on experience. Heart rate data shows that both runs were above what’s considered to be a manageable and recommended for the duration/distance. I’m working at a higher % of threshold heart rate or possibly above for quite a long duration. So my question is, why can I do this, what type of athlete am I (strength and weakness), what type of workouts would best develop my fitness, how does or will racing at such a high intensity limit my potential, is it physically safe?
On the bike everything is power with heart rate only been a secondary measure more out of interest. I know heart rate is higher running as opposed to cycling but at 94% of max for 2hrs45 seems high so I’m looking into exploring why it might be so high and what it means for me going forward with my training.

I’ve never pushed to the point of blacking out but think that max can be determined over time a good estimate can be gained from tough workouts.

Yeah I know my runni g heart rate is higher I found that out first time I started cycling.
I said tough hill sessions, as in multiple repeats. Threshold heart rate is usually described as between 80 and 90%of max. I ran the marathon with an average of abound 94% of max.
Agree there are many factors to consider but even with a bit of tolerance to allow for these factors it would still seem that I race at a high %of max heart rate or threshold hr if you’d prefer.

Don’t think I was dehydrated at the start of both races plus neither was I’m hot conditions.

The garmin predication isnt worth anything I know I was just using it as an example of how I fall outside of the recommended zones. For example on. Sunday it gave me a predicted marathon time as 2.55 based on a threshold pace of 3.55km which it generated from a estimated heart rate threshold of 165bpm which it gained from a run with a heart rate average of 170bpm for 2.45 hrs at an average pace of 3.53km.

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Seems quite likely that this is a flawed assumption though. I don’t think you should take much from race HR.

As above, HR can be affected by a lot of things… I did an hour long Zwift race last year and averaged 183, that’s around 95% of my max… But it was indoors, so I had relatively poor cooling, and with adrenaline from the race, and lots of successive very hard efforts (trying to make selections on climbs etc). It is quite hard to actually get to MHR, I don’t usually get there at the end of a ramp test (usually top out at 191-ish whereas in race-type situations on the road I can see 195). I’ve never averaged anything like that in training - threshold intervals would be in the 170-180 range.

Out of interest, what was your bike power vs FTP and was your ratio of HR to power significantly different to normal? I.e., was your HR much higher than usual for the power level.

I don’t start off TTs dehydrated either but I guess it crops up through the event, that and building up HR continuously (rather and up and down continuously in intervals) and in a cooled environment that let’s you build it up more sustainably. If you tried to build up your HR indoors with a continuous effort, I suspect that the lack of cooling would be a barrier. Just looking at my TTs, over the last year, I’ve averaged 180+bpm on a lot of them but I have only managed circa 160bpm average indoors. It’s been summer ish here so far and looking back at previous years with more winter that disparity has been less but its still there👍

Most likely your max HR is wrong. I wouldn’t draw conclusions about you as an athlete and how you should train from a wrong measurement.

If you want to train by HR, look at your threshold HR, and set your zones by that. Realistically, HR is too sluggish to respond to most short efforts above threshold, and you couldn’t train by it then anyway. It’s more useful for the easy, endurance, tempo, and threshold zones - and there you don’t need to know your max.

Even if your 95% is actually taken from a correct max-HR for that sport, and you’re always at this high a percentage for your sustained (e.g. marathon) pace, it doesn’t really mean a lot. Like multiple responses have already said, try to find your actual threshold heart rate and use that for pacing/zones. But be prepared that you may still see large fluctuations, and even if you don’t see them, zones may still not exactly line up with the percentages quoted in training literature. To complicate things further: with training the heart rates you see may also change. E.g. my (average) threshold HR is substantially lower than three years ago, my max-HR is practically the same.

I don’t think there is any relation with how/what you should train or your “athlete type”. Just train for the kind of efforts/events you want to do. If you want to use heart rate zones for training, validate them by other means than your max-HR.

From what I’ve read, world class marathoners have a very high lactate threshold heart rate. Somewhere around 90-95% HRmax. That along with running economy and a high VO2max is the reason they can run at a pace of 5 minutes/mile.

Can’t answer your other question - I’m not a runner, coach, or physician.

I think what people are saying here is that the day-to-day variability of HR and the inherent difficulty in determining accurate zones means that you may not actually be that close to threshold (and per the definition of threshold, it’s highly unlikely), so you can’t really determine anything meaningful or actionable about athlete type or training from that. Train for your goals.

The key point here is that threshold is not a heart rate, and intensity is not determined by a heart rate. These states are byproducts of physiological and metabolic processes- metrics like HR and power are just a proxy to guesstimate and more effectively target these zones. Any one taken outside of context is essentially meaningless, and when it comes to using them prescriptively they’re more to guide your own judgement than to be the Sole Arbiter of Everything.

Regarding safety: again, use your judgement. How do you actually feel? And as always, seek professional advice if you’re concerned.

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