Haven’t done lactate testing but have opinions. For myself, it’s the top end that gets blunted. But my coach says, “if you want to lower HR then I’ll have you do some back to back 20 hour weeks” (I can only sustainably recover from ~10 hour weeks).
It’s a joke. I can temporarily drive HR down by doing a few big weeks. FWIW I’ve posted power @ my “all day HR” (~140bpm top on Friel HR z2). Basically it went from 150 to 200W over two years under my coach. Round numbers.
No, you should train according to power zones and leave heart rate as a secondary metric. Heart rate is influenced my many things, including fitness, fatigue, sleep (quantity and quality), illness, etc. Apart from pacing mellow endurance rides, I do not use it as a primary metric.
To address your questions, though:
Yes, it is normal that heart rate in a specific power zones decreases as fitness increases. So if you do lots of endurance rides, your heart rate in Z2 will tend to be lower. 10 bpm jives with my personal experience.
Not just heart rate in absolute terms is important, but how your heart rate changes over time. E. g. if you are doing hard intervals (threshold, VO2max, whatever), how much time do you need until your heart rate goes back into Z2? When I am trained and well-rested, it is <90 seconds.
There is typically no simple way to draw conclusions from a single data point. To me one of the most useful metrics for how hard a workout is to look at the heart rate recovery time (see previous point) and how that develops as I do more and more intervals. The first one gives me an idea of my overall level of fitness, they give me a baseline. If my recovery time explodes, I know I might have to push hard to finish the workout or call it quits.
Heart rate lags behind and is not useful to pace shorter efforts.
Heart rate is highly personal. Some people have a higher heart rate than others in specific power zones. It doesn’t mean they are more or less fit, just that their heart has adapted differently to the demands.
HR is useful as an additional, secondary metric to inform your training, but not suitable as a primary metric if you have power data.
No, lactate heart rate changes with fitness, too. It is just that your heart rate range is much narrower and don’t change as much as power zones might. In my case, heart rate in specific power zones can change by 10–15 bpm.
My two cents: Over a medium-long period, an improved pwr/hr relationship very likely means increased fitness. Provided that perception of effort or rpe agrees.
Over a short period, it could be fatigue driving things. I experience this a lot, hr sinks thanks to load as it were But then we have perception of effort to double check. If the same wattage creates a lower hr but feels harder, fatigue is probably the main driver (which doesn’t rule out improvement, just that for the moment the fatigue effect on hr dominates).
Would not worry too much about increasing Z2 watts as such as long as Z2 rides are in the zone and facilitate overall training goals. Conversely, if upping the watts does not interfere with other rides, no problem going for it as long as you stay in zone.
I’ve been training for about 1.5 years now. In that time ive learned (and I keep trying to apply this knowledge) that heart rate is a bit limited when trying to assess fitness gains.
Hard blocks of volume and will drive my heart rate lower. “Suffering,” having a huge mental aspect, can correspond to that RPE and tell me it doesn’t hurt because my heart rate is low. It’s fine at Z3 and Z2, but higher than that when the heart rate doesn’t rise to meet the demands the RPE goes up.
Adding to this, the Garmin watch I run concurrently with my KICKR, “rewards” me with a higher VO2 max score when I’m fatigued! Take a rest week, heart rate rebounds, and Garmin tells you that you’re now “unproductive” and lowers your VO2 max score. Very frustrating. I know, just a number, but let’s be honest, we live by these numbers and ignoring them is much easier said than done. For all of us.
I’ve been tempted to hide my HR info and just go by power and feel.
Taken as one liners without context makes you and others misunderstand what I said.
I said for me, the lower fatigued heart rate during Z2 and Z3 rides (IE, In my target zones), doesn’t matter much because the RPE is still low. Its when the RPE gets higher yet my heart rate doesn’t respond concurrently.
Disagree with the limitations of heart rate all you want, but the fact that heart rate has so many variables makes it susceptible to inaccuracy when trying to compare different sets of data. Fatigue, hydration, humidity, temperature, elevation, etc etc, heart rate will respond differently. I did not say its a worthless metric, and I wear my heart rate monitor every ride. Yes, ultimately you can look at trends. If you stay at 180 bpm at 200 watts and never improve that metric, you aren’t improving. However, I think with heart rate you need to look at very long term trends.