on a ten k for me i start at 160 pretty quick and end on death's door around 170. most of the time i am 166 plus. but hr is different for everyone, just train with hr and race with hr and figure out your normal.

My heart rate would go up to 189 beats per minute within a quarter mile and I would hold that until the last half mile or so. My heart rate would go up to around 200 at the end of a 10K.

Could be cardiac drift: the tendency for the heart rate to increase over time at a constant rate of exercise.

https://www.polar.com/...-effect-on-training/

Cardiac drift it is. I can hold a pace like a swiss train and I see it all the time in my data. The curve looks like a nice inverse power equation for the first mile, mile and a half depending on pace, then it keeps creeping up to potentially mrh depending if the pace is sustainable, otherwise the pace has to decrease.

Wow very interesting! Thank you for sharing!

What pace are you running at? If I am doing 10 km and run at 5min/km pace it will take a few minutes to get to mid 130's and may drift a few beats higher over 10km start to finish. If I race at sub 4min/km it will take a few minutes to get into the 160's and probably get into 170 to 180 range by the end of 10km.

On the occasion that got my interest it was indoors and I was sweating quite a bit so that’s why I’m thinking it may have be cardiac drift. It was a 5min k pace.

Compared to another run the other day outside when it was quite cold I ran the first 10 at a 4:32 pace and whilst my heart rate did increase to 179 I then backed the pace down to 5min ks and my heart rate steadied at around 170 for the next 5 and felt really good.

So you’re wondering if it’s normal to have a high heart rate while racing a 10k? Really?

No, not so much a high heart rate. More wondering at what point should it plateau. I guess my questions comes from looking at the 15k run I did the other day where my heart rate stabilised around 170 and felt very comfortable-I could have easily just kept running, yet yesterday I did a 10k run and my heart rate kept increasing until the 10k mark where I was pretty gassed.

I checked my heart rate and the two profiles where quite different. The easy run (though a faster pace) had a flatter profile, where as the slower run that I struggled with had a heart rate that just kept going up and up...

In my experience you really have to both have a larger pool of (your) data to draw from as well as take into account the circumstances of your individual run if you're going to look at individual runs. Everything from weather to topology to how rested you are to your pace will determine just where you'll end up as far as HR goes. If you didn't recover properly or didn't get decent rest then it's no wonder your second run made your HR / effort higher.

I stopped measuring HR years ago but I did gather date for several years before I stopped. My last race where I had an HR belt was a 5k. I think I warmed up pretty well before and I was pretty fit for my age. So those two things meant that my HR went up pretty quickly, dropped down a bit and then stayed flat until the point I decided to just go all out to the finish meaning I ended at maxHR. So compared to a lot of other runs I've done that's actually very flat. On other runs I've perhaps aimed for anywhere between 8 and 14 miles easy running, and when I do the first couple of miles really serve as a warmup so my HR doesn't reach a steady level until later.

So as others pointed out I don't think it's abnormal. With time you'll know what to expect.

Some days you have more stress.

Some days you have less stress.

Simple.

Why are you running 15km at 170 is more the question? That is a hard run. Now after stressing your body that much considering you're running at close to threshold at 5km/hr pace you are going to be fatigued. You need to be doing your long runs at a much lower heart rate so I am not even going to try and guess what is going on.

I don’t know-like I said it felt comfortable to me, I certainly didn’t feel overly stressed and could have easily done another 5. What would you recommend? 150 bpm? What about for a 5k run?

How old are you? Have you been running long? It would be worthwhile working out your HR zones and building a plan based on that. Long easy runs are to be done easy and hard runs are to be done hard but not all runs hard. My easy runs are around 140 and my coach will define a HR limit or pace depending on the session and where I am at in my build. It seems that if you are always training at the level you are you are always going to be dealing with fatigue and most probably not getting the gains you could.

In my forties. I’ve always run but this year is the first time I’ve actively tried to get quicker as opposed to longer. I had tried zones in the past but found running slow felt so uncomfortable that it did my head in, maybe I need to try again and persist...

My coached has forced me to run slower and as much as I hated it and it felt horrible to run slower it feels better over time. Mix it up with interval or fartlek sessions double run days even rather than just run hard every run. I'm in my earlier 40's and can't push at heart rates you are for that long as much any more without paying for it and not being able to back up sessions. Time in that zone is has to be more specific.

170-180 bpm felt comfortable to you?

Are you talking a regular run or a race? Your original post made it sound like a race.

In any event, I don’t really believe in training by heart rate, but unless your reallly young there’s really no way your heart rate should be in the 170s on an easy day.

Keep in mind your max HR may be high. Could you have a conversation at 160bpm? If yes, your max may be around 195-200, and your anaerobic threshold may be around 175. This would explain a just-below-AT HR that can be maintained for a long time (170 for you), and a level just above it that starts the tea-kettle boiling (175+).

I know for me that I can go just under AT (for running, mine is around 160-164) for almost 4 hours, but just over only for 1-1.5 hours. And WAY over, like for a 5k, hurts like hell and goes up and up like you're describing (for me, 165-175 at the finish).

This is entirely dependent on your physiology, and it may be that for you, under 150 is total recovery pace. Great. Learn what each HR maps to and then use the information to inform your training. But don't go nuts about keeping it under 150. Your 150 may be my 130 -- like I said, totally individual.

-Eric

Dunno,

If you look at my chart from Garmin you'll see what an all-out effort looked like for me about 3-4 years ago. I was about 44 at the time. So at that age I could manage about 200bpm as a maximum heart rate. I'm above threshold for most of that 5k. At that time running 170bpm for some time wouldn't be a big issue for me (today it might) because I was in good shape.

But like Shambolic said, if you're going to look at your HR you really need to figure out what your zones are, and that will involve figuring out what your maximum is right now. If you know what it is then let us know sine it's going to be easier to figure out if you're running your easy efforts too fast.

Intuitively though I'd say that if you feel like "running slow felt so uncomfortable that it did" your head in, then you might have a general problem with easy running. I know people that have the same emotional response to running slowly and they end up not training optimally as far as I can tell.

PS: I agree with Eric.....

If this is happening during races, then it's fine - Peg it out at the end. If this is happening during training, and you are running like this all the time, then you are training wrong (too hard).

It's hard for us to know which you are talking about because the distances you are mentioning about are also common race distances.

So are these races or training runs?

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Regular run, the first 5k hr averaged around 160 but then increased constantly up to around 174.

I wouldn’t say it was an easy day but by the same token I wasn’t out of breath and could easily hold a conversation

Chest strap or wrist HR? Have you done any testing to establish zones?

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Interesting! Sounds similar to me, yes can easily hold convo at 160; even at 170, but the slight increase definitely boiled the kettle-not so much from being out of breath but more the pain of the lactic acid and general discomfort