The main one where I heard it was our XC race that was less than an hour. But I also heard it from a couple in our road race that was just under 2 hours for some riders. Sort of two notable differences there, so I know people might handle them differently, but some here were locked onto HR for sure.
- Barring technical issues, it really is. The power data doesn’t lie or change based on the items below.
- How we experience and handle that truth is the crux & human element here
It’s only after spending 8+ years messing with this stuff, making TONS of mistakes and such that I have better tuned my RPE in particular, with Power & HR as references. Bigger picture and all that noise 
Couldn’t disagree more. Power meters measure work effort. Heart rate monitors provide information on how your body is reacting to that effort (and other loads like heat, life stress, fatigue, caffeine, etc.). Example - if I go for a run at my normal pace (work effort) in Florida heat/humidity of summer, then my heart rate will show me there are additional loads on the system (body dealing w/ heat).
Perceived exertion provides more. And, it’s always there, even if you forget to put on your heart rate strap or the battery is dead.
PPP: If you know your power, then at best heart rate is redundant, but at worst it is deceiving.
Don’t think I’d ever knock off an effort because of HR if I was hanging on - it’s always a theoretical anyway based off tests. My race screen is distance, time, HR and power - but when the racing’s on I don’t think I ever look at it!
My story is this: I had trained for a 30 km running race in Houston wearing a HR monitor (pace not meaning much when you’re running on a beach, weaving around shipping detritus, blobs of oil/tar, and dead jellyfish). My goal was to break 2 h. I hit the 1 mile mark right on pace, but my HR was ~10 beats/min higher than expected. At that point, I had two choices: give up on my goal, or choose to ignore my HR. I opted for the former, and barely squeaked under 2 h, really pushing hard the last couple of miles into a headwind and finishing on dead legs.
(Of course, there’s also the time I did a 40 km TT in the heat and humidity of Florida, where despite being well-acclimatized - since I lived in Galveston at the time - my average HR was higher than my normal maximal HR.)
I agree, if I was only allowed to have one, I’d take my body’s own monitoring system and senses - perceived exertion. Load side measurement (power meter), body reaction side measurement (RPE, HR). There is a reason experienced and pro cyclists/coaches still use HRMs.
Depends on how they’re using them.
Looking at HR data post-ride as a data point is a world away from using it during the ride to determine how to meter one’s effort.
Yes: it’s a tradition-bound sport, very slow to adopt new ideas. Just look at how physiological testing is still valued by that community, when bigger thinkers like Frank Overton or the AIS have long moved on.
Even the undergraduate ex sci student/collegiate runner is smart enough to independently realize that such testing usually doesn’t provide any “actionable intelligence”. How is it that she “gets it”, and yet folks like ISM don’t? (That’s a rhetorical question…there’s a reason she’s going to make an impact on the field after she gets her PhD.)
For Z3+, power has priority, don’t care about HR (2-3x per week). Only look it at post-ride, even hide it from headunit main display.
But for Z1-Z2 (12h+/week), I still go by HR cap – no single workout affects me much but exceeding some certain HR threshold (146bpm for me, with 180bpm LTHR / 205bpm observed max HR) over extended periods (weeks/months), I know I will lose motivation first and then everything else falls apart.
I don’t agree. I’ll give an example. I live in Florida, where our heat and humidity in the summer gets us to 115 deg heat index, and stays elevated even in the late evening. I’ll use my heart rate to monitor my bodies reaction to this heat. It will show me this additional load and make me aware of this situation before I start feeling sick from overheating. I’ve been doing this for 32 years.
And even bigger thinkers (Dr. Stephen Seiler) have still not “moved on” from HRMs. 
I will put the same challenge before you that I have always suggested to others: come up with a use-case in which heart rate provides actionable intelligence that can’t be obtained from power and perceived exertion.
(Heck, even the context of stress testing of cardiac patients - something I did every Tuesday afternoon for about 10 y - the first thing my cardiologist friend would always ask when something seemed amiss was not “What’s the heart rate?” but instead would ask the patient “How are you feeling?”.)
I wouldn’t describe Seiler as a “big thinker”.
Your perceived exertion doesn’t tell you how your body is reacting to the heat? (Again, rhetorical question: obviously it does.)
That’s the thing, I keep feeling fine for months until I don’t and then it is already little bit late. It takes roughly 2 weeks to get appetite for riding back.
You could achieve the same end result by ditching the heart rate monitor and going by power and perceived exertion.
Afraid not, that is my point: every single workout I still feel fine and whatever Garmin measures (resting HR, overnight HRV recovery) is still ok but motivation is gone if I don’t limit myself during Z2 workouts over long periods
EDIT: I think we talk from slightly different angles:
- for any single workout: agree, power + RPE is sufficient
- but for whole season, I need to keep myself back because short period appetite can derail longer period capability
Through my own experience I’ve found that using HRM keeps me from overheating in Florida summer. My problem (especially when running where there isn’t the level of cooling) is that heat exhaustion comes on rapidly (a feeling of nausea) and stays there for a while. Using an HRM I’m able to prevent that from happening. My study has been ongoing for 32 years and found to be effective in this regard. I’m publishing it right here.
Same here in Northern California. Did some 30 second intervals last night in 100F / 38C air temps and capped the “endurance” at heart rates that I know will avoid feeling like crap the next day. Looking back, power was 120W for awhile and then 90W for awhile to bring HR back down. Hot riding for 102 minutes total last night. Feel great this morning. Learned those lessons 7 years ago.
And no, I tend to ride too hard on RPE and find it easier and better to look at HR every couple of minutes.