No PM, adjust HR zones for

I’ve been on vaca for the last 10 days and training on a bike without a PM so using HR zones to guide my tempo and sweet spot efforts. I live at 5000ft but training at under 1000ft. It seems in addition to breathing being easier it is difficult to raise my HR despite my perceived exertion being fairly high. Totally unscientific but seems my HR is around 10-15 bpm lower. Is that normal or all in my head?


That is interesting to hear. Like you said we would expect your power to be higher, but heart rate and perceived exertion to be still similar to effort.

When we coach athletes that are traveling to lower altitudes sometimes we suggest doing higher intense efforts so they can hit the power they normally can’t at a higher altitude. We find benefits to them doing vo2 max intervals. Going from 5000ft to near sea level you could expect as much as 5% or more increase in power.

So maybe what you are feeling is doing these higher watts, 5%+ for sweet spot so it just feels harder on a muscular stand point. Still doesn’t quite explain the lower heart rate. Heart rate has so many other variables as well so hard to say. Could just be general fatigue, not getting enough sleep, and etc. Things that can happening easily on vacation.

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Any chance you’ve started a new medication recently?

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good thought but no. felt rested and not overly stressed so peculiar but I’m back home now and going to be dealing with some altitude reacclimatization.

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interesting HR and power observations upon my return to 5000 ft elevation after two weeks at around 750. first ride was 3 hrs endurance with late sweet spot and 1 min full gas efforts. I felt fine for the first 30 minutes or so although I did notice my HR was slightly elevated.

then things went downhill - one hour into the endurance effort I was barely holding the low end of zone 2 power but my heart rate was hovering at the top end of zone 2. with 30 min remaining I dropped below zone 2 by 10 watts and heart rate was at high end of zone 3.

when it came time for the sweet spot effort I went quickly into subthreshold and couldn’t maintain the prescribed power. I pushed thru the full gas efforts at just barely above threshold.

for the entire 4.5 hr ride my average power was 152 watts and despite an average HR of 144 my TSS was a dismal 175 (~39 per hr). felt like that number should have been well above 200.

So basically it sounds like you had the opposite problem now with an elevated heart rate. Well altering being a sea level or near it for 2 weeks I would expect elevation to be a factor in the reason heart rate and perceived exertion would be higher.

Without actually seeing all your training it is really hard to answer the how’s and why’s you maybe feeling a certain way. Most of the time it is a simple answer but maybe a complicated way to get that answer. You either need rest or to train more. My guess is you have been training a lot, even been training on vacation. Not sure when or what your goals are but at some point look to take a midseason break. This can help bring back some freshness! That maybe just what your body needs.

Another thing to look at is how you may want to change up your training a bit.

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thanks for your input and insights coach @Jake

definitely perplexing and today’s 5 hr ride just further cemented something is not quite right…

hoping it’s just the changes in altitude making things wonky and I’ll reset once I get re-acclimated.

@jamestevens training zones are an important tool in any training plan but only if we know they’re accurate and in periods where you can tell they’re off, you might do well to ride by RPE (or test).

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