Cannot raise HR

Hello all,
New-ish to TR. Been following a plan for IM Chananooga. For the last few weeks I have been unable to raise my HR. I am an hour into Sandy Bay, even at 110%, my HR is still in Z1.
Sounds good, except trying to raise it seems impossible. Even for an sprint interval session my HR will not raise above the begining to Z3.

So, good thing?


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HR response is very individual but for an endurance workout like Sandy Bay I’d pretty much expect to stay within Z1 for most if not all of the time. I tend to do longer endurance stuff outdoors but the last long(ish) endurance workout I did indoors was Fletcher - my max HR was 124bpm (top of Z1 is 132bpm), here’s the distribution (from for the 90 minutes of effort.

Depending on which interval workout you did, it’s quite possible that the recovery valleys let your HR drop sufficiently that you don’t really raise your HR. Plus it’s not really the point of sprint workouts.

Try a threshold workout like Mount Hope-2, here’s my HR distribution from that:

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Are you on any medications? Several of them will keep HR down as a side effect.

How did you set your HR zones?

Is your HR really not going up, or just not in the zone you think it should be in? (HR zones and power zones very often don’t match up).

If this is a new thing, it could be that you are tired or sick - a muted HR response during exercise is often a sign of tiredness (plus usually an elevated resting HR).

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Maybe your HR monitor is incorrect?
I know from personal experience that my wrist based Garmin never reacts to changes in intensity (and often doesn’t accurately represent my HR at all) as well as my chest based HR monitor does, especially during indoor sessions

^^ this is real, and assumes you have a good idea of what your HR should be and day after day it’s consistently low

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HR is a very individual thing, my self for an endurance workout at circa 70% I would expect on review to find my self mostly in HR Z1 with flurries into HR Z2. Theoretically if I had been typically doing Endurance wo’s in HR Z3 and for this one off I found my self in HRZ1 I may start questioning is it a bug, am I overtrained or am I just getting fitter but to be honest Id mainly disregard HR.

Depending on which HR zones you are using! With Friel I get HR zone2, with Coggan I get HR zone3. HR zones are highly individual, and different zone models will give different results. Comparing HR to power only makes sense in the context of an individual.

Disregard HR? Never. Some will say HR is too variable, but relative to power zones my HR is very stable and predictable. I can predict changes in fitness just by looking at power-to-HR for each power zone.


I wouldn’t totally disregard HR either but I wouldn’t put too much emphasis on it either but if its good for you use it :+1:

Agreed so far sprints have been short enough to not get much of a HR rise. My last threshold session was Tinker-2, hr still not out of zone 3.

I used to have my garmin on because i can only get HR data into TR with a USB/Ant+ dongle on my phone. But after they agreed so well , I stopped so mt garmin wouldn’t keep double counting my rides.

No new meds. Thank goodness!

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HR based on max HR test done with garmin, and dumb trainer, before had power data from kickr core. Basically a ramp test ,dropping a gear every min, but was only monitoring for a level HR after two minutes at max. Unless my max HR has come down, I’m pretty confident it’s correct.

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Hmm, maybe. Been hitting the bike and run pretty hard lately because I’m tired of being so darned slow.

RHR has been steady, trending down. Yay!

Confident in HR reading. I use garmin tri-hrm.

I had been basing my HR response on power, but I have been trying to pick up the cadence. Last fall my outdoor rides avg cadence was about 84, now I’m consistently hitting about 97. I’m thinking I can’t be putting too much stock in it though. TR can make the recovery watts very low, where outside I have a minimum power requirement to keep up the cadence.

I get that endurance rides “should” be Z1-Z2. But I usually end up on the high end of Z2 for the majority of the duration. Once I noticed it was staying in Z1, I tried raising the resistance to bump it up. Maybe I just aughta count my blessings, zip my lip, and trust the adaptive training. :slightly_smiling_face:
About to get into specialty phase with another ramp test. Maybe I’ll bump up a couple notches? Thank you all for your input!