Hi All I know people have discussed power vs heart rate endlessly but I still haven’t found an answer to the below question so if anyone who understands physiology better than myself is able to answer this, it would put to bed a question I have had for a couple of years. Question: I am doing Zone 2 low level rides. Power wise this equates to 146-198 watts Heart Rate wise this equates to 116-154bpm Whichever data you use, both are trying to do the same thing…work at a low enough intensity to improve your aerobic base which should build new capillaries, increase mitochondria and improve your body’s ability to use fat as a source of fuel on endurance rides. This post isn’t asking whether heart rate or power is better, (I know why TR prefers power due to its consistency and that heart rate can be affected by numerous external factors) but my question is this: If I use my zone 2 power to ride to (upper end 198 watts) my heart rate will rise to above 165bpm. How can I build an aerobic base if my heart rate is at 165bpm or higher? That is 83% of my max heart rate. (Extra info: I am 45 years old, 73kg, 172cm tall with max heart rate of 198bpm). I guess what I am trying to understand is if we know what physiological adaptions we want from zone 2 riding and that these adaptions require plenty of oxygen to make them occur, how can power and heart rate zones be so different and elicit such different heart rate responses from the body? Knowing the answer to this would allow me to understand which one would be better suited to me (and anyone doing low level training whose heart rate is much high when in a zone 2 power zone). In the meantime I am sticking with heart rate zone 2 as this is the lower intensity so at least I can’t go too far wrong. The past few years I when doing sweet spot my heart rate can sit at 90% max heart rate so you can imagine how long I last on Over/Unders. This year I thought lower training initially to see if it helps when I get to the high intensity work that requires active recovery. I’m not a physiologist so if anyone answers, please keep it simple…imagine talking to your 6 year old lol. Happy riding all :slight_smile: David

I’m assuming you’ve calculated your HR zones based off max HR. How have you determined your FTP? Ramp test? 20 mins test? Do you have enough historical data to check that your power and HR zones do actually match? For example, have you done multiple threshold workouts and seen that your threshold wattage matches your threshold HR? I would start there and then work backwards if it was me.

I’ve done 4 twenty minute tests, 3 ramp tests, (ramp tests for me seem pointless as I over score on those and get readings that inflate the ego but practically are not useable) and 2 of the Sufferfest 4DP tests, (ugh) However, my question was more about if two different sources of data are supposed to be achieving the exact same thing, (aerobic improvements with all the benefits that are attached to them), how can they be so different?. I have seen other people with completely different heart rates and power numbers when also matching their zones so I don’t think I am unique. I’m sure I read that when comparing HR and power, they often provide different numbers so not to expect them to match but that just leads me back to how can notably different responses provide the same outcome? I will wait for someone to now use the phrase, ‘There’s more than one way to skin a cat’ lol.

[image] Day: However, my question was more about if two different sources of data are supposed to be achieving the exact same thing, (aerobic improvements with all the benefits that are attached to them), how can they be so different?. It is my understanding that there is one aim here (zone 2 development) and 2 methods of measuring (HR and power). I suspect they’re “so different” in part because at least one of them may not be correct for you. If zone 2 power does not give you zone 2 HR then maybe one of these needs correcting.

Little bit of info here that may be useful: [image] Heart Rate Zones (HR) vs Power Zones Training Not really. [Power vs Heart Rate: How Modern Athletes Train] Full blog post (that also includes the video): And older info: Training with Power vs. Heart Rate - TrainerRoad Ask Chad - Power vs Heartrate - TrainerRoad Blog

Seems to be quite a lot of data out there that there’s little to no benefit in working at the upper end of Z2 vs lower end. So if working at the lower end of Z2 power also means you’re keeping your HR in zone 2 then that seems a sensible approach. Also agree with the comments above that one or both of your zones may be wrong. Personally I find quite a bit of variation in HR depending on time of day, temperature, fatigue, caffeine, etc so I tend to use it more as a sense check than as a metric to guide training intensity. Useful sense check on Z2 rides for me is whether HR is staying pretty constant after the initial warm up. If it continues to rise significantly while holding steady power then that’s normally a good sign that I’m working too hard.

That was my thought but I would love to understand the Why in order to be able to make the best decision. I know TR push power due to the fact it isn’t altered by fatigue, hydration, temperature etc etc and that you get the same workout each time, (so far more consistent for controlled improvements). But if that is correct, are they saying heart rate is irrelevant and just let it go as high as it wants as long as you are hitting the same power each time? And if that is true, how can a higher heart rate provide aerobic responses if it is 10-12 beats higher than a previous workout due to external factors?

[image] Day: That was my thought but I would love to understand the Why in order to be able to make the best decision. Why what? [image] Day: But if that is correct, are they saying heart rate is irrelevant and just let it go as high as it wants as long as you are hitting the same power each time? No. That’s why the workout screen gives you an HR reading. The podcast team have always (from what I can remember) recommended recording and monitoring heart rate, just not basing your workout intensity on it. For what it’s worth. I also have concerns about HR being often discarded. Just because caffeine, for example, may elevate our HR, does that not mean that we should still heed this extra work that the heart is doing and adjust our riding intensity accordingly? I suspect the answer is somewhere between what is best for training and what is best for health.

And more reading here: Ask Chad - Power vs Heartrate - TrainerRoad Blog This is the second post in a new series where Chad answers training questions. This question came in through support.trainerroad.com. I have a question on this topic: How much do you think a persons goal would affect whether they use...

Aerobic decoupling Just skim read your posts between meetings - take a look at the link above to see if this helps.

[image] Day: I know TR push power due to the fact it isn’t altered by fatigue, hydration, temperature etc etc I think it’s more that they push power because the power curve and hence zones are more predictable from a single test than HR curve/zones are. The power you can put out is absolutely altered by fatigue, hydration and temperature - try doing VO2 intervals while tired, dehydrated and overheated! But all things being equal (i.e. assuming fatigue, hydration and temperature are in the same ballpark for your workout as they were for your FTP test) then having a decent FTP estimate enables you to have pretty decent estimates for the zones above and below threshold. Yes, there will be outliers who skew towards the aerobic or anaerobic end of the curve, but you’ll be close enough for most people. I’m not at all sure the same holds true for HR. For a start you probably need 3 data points, not one, to estimate zones - Resting HR, Max HR, LTHR.

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Heart Rate & Power Info

Training

onemanpeloton November 9, 2020, 11:12am 5

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