I’m opening this thread for a broad discussion about different approaches to training with heart rate. Or just observing it.
I’m interested in what are your experiences with the different heart rates and the same power input on different days. I was amazed yesterday, while riding a 60-min Zone 2 with 65 % of FTP power, that my heart rate was constantly around 140 bpm, but every other time is in the lower 130s. Two weeks ago, it was averaging 124 bpm.
What are the main causes for this kind of fluctuation in HR?
Not everyone is the same. For example it’s common for someone carrying fatigue to not be able to elevate HR particularly high. I’m the opposite and when I’m tired or sick my HR soars.
I’m no expert so take anything I say here with a pinch of salt but if you’re seeing huge deviations from the norm (124bpm at a given effort is now 140) then I’d assume you’re carrying some sort of stress. Could be viral. Could be anything.
Hydration plays a huge role also but I can’t say I’ve ever seen my HR increase by 15 bpm because of poor hydration.
My own HR increased by 20+ beats at end of July just year after contracting COVID. It’s still not back to pre COVID levels… Not even close.
Heat can also have a big influence, but again not to that degree you outlined above (in my experience)
I’m one of the “Covid Born” cyclist and only started following some kind of training structure last year in January, so I’m kind of new, but I love data and I love analysing trends with power and HR.
First finding - Heart rate will increase for the same power after a while. (Cardiac drift)
This is pretty basic, for me after 20/30 mins the HR will start to slowly increase.
Second finding - At the end of a training week, most specifically after a long ride (+4h) my heart rate will drop significantly.
So, the day after, I notice that my heart rate is way lower (maybe due to fatigue?) that it normally is, sometimes, the HR was even 10 bpms below.
Third finding - During a ride, if I do an hard effort for 5 or more minutes, going uphill for example, I notice that my HR will be more “volatile” for the rest of the ride. Like any effort or small surge will cause a big jump in HR, and I even feel that for the same effort I’m having higher bpms than usual.
on very long but slightly intensive rides, e.g. multiple hours tempo rides, your avgHR and “ability to hit high HR” will decrease over the time however power output will be also lowering.
training/ride day after high intensive training or block of training might be resulted with lower than usual avg HR for comparable power outputs
training in high temperature might result with significantly higher avgHR for same power output. For instance, last year I did a 2h endurance ride in 34deg temperature (while 30deg is already hot in my area) and my avgHR from this ride was +20 more than usual despite of extra hydration that day.
I’ve also checked my HRV (I’m using Garmin’s Forerunner 955) and tonight it dropped (from the 7-day average) 66ms to 56ms. There’s something there. It’s really strange because I’m feeling really good - I would understand if I would feel a little off … so interesting.
First finding - It will drift if you’re not efficient at that power. The more efficient you become at a given range the less drift you’ll experience. General rule of thumb is anything less than 5% Pw:Hr drift on an endurance spin is what you’re looking for. See below - little to no drift for my 4hr spin
Third finding - Again down to efficiency and conditioning. The bigger your aerobic base is the quicker you’ll recover, the lower your HR will recover too and the more stable it will remain.
You can look for the highest value from a recent activity. Note that racing might not always give the highest value. Look for the duration that gave the highest value, and then repeat those maximal efforts occasionally to keep it updated.
A maximal effort, eg. 3-5 minutes, preferably up a 3-6% grade is common for the athletes I can see. My max comes from an effort closer to 3 minutes.
This is for cycling. For running, I’m not going to comment; not my strength.
About 3 or 4 years ago I did a ramp test. 1 minute intervals to exhaustion, increasing by 20 watts a minute. But I don’t ever use max HR for anything tbh. It’s just another number that actually means nothing. It literally only tells you what your max is and basing zones off this is not a good idea. It doesn’t tell you where you’re most inefficient. It won’t tell you where most work is needed. It won’t tell you your aerobic or anaerobic thresholds, despite what the zone calculators will have you believe. So doing a max HR test is a complete waste of time and effort in my opinion But that’s just my opinion!!
Agree that you shouldn’t specifically test but if you have a couple years of historical data, taking the max HR that occurred should be a very good estimate. Just make sure to check the HR trace it gets that value from to be certain that it wasn’t an artifact.
If you want to use the decoupling chart on the Power page or use HRSS to calculate Load, you need a HRmax value!
The ultimate best way to set HR zones is based on physiological parameters AeT and AT. But that requires a lactate test or ergospiro-test.
Second best way is to base them on LTHR obtained from a 20 min test.
Ideally I’d have a lactate measuring device and I would set my aerobic threshold from that. But I don’t!!
What I do though is a ramp test, increasing by 20 watts each ramp. This is not a test to exhaustion though. This test will show a HR inflection point at each threshold. This gives me a rough estimate. This is all I need really because regardless of what a graph tells me or an FTP tells me, I am long enough training to know where I’m at. On an endurance spin my breathing will give me more feedback than any metric. I just know if I’m going too hard and I can back it off. I couldn’t care less what my FTP is because I know what I can and can’t do at any given stage in training. So ‘Zones’ are only really there as a visual on paper and to get a fair idea of how I’m increasing load over the course of a block. You cannot do an FTP test or a Max HR test and simply base your ‘zones’ off these numbers. Your body doesn’t work like that. I would nearly guarantee that 99% of people are setting their top of Z2 in a 5 zone model too high if they use the FTP or Max HR number to set it.
Heart rate is not supposed to be used in isolation, but rather along side RPE and Power as a measure of what’s happening inside. Power is mechanical, while HR is biochemical, and RPE is subjective. If one of them is off, eg. HR doesn’t get up to an average of 90% of maxHR (the range could be 85-95%) of any of the threshold intervals, yet you are pushing the power, it could be a sign that you need to back off due to fatigue, or the onset of fatigue.
Also, maxHR will decline with age, but not 1bpm for each year. That is why you test, so you can see where the max level is.
edit:
Why a certain level (% of maxMR)?
Firstly because not everyone has access to testing lactate threshold. Secondly, one can’t test lactate on every ride (too expensive and also too invasive). Thirdly, % of maxHR is where many people will fall into (bell curve). If that’s all you have then that’s all you can do.
Another point, is that if you are targeting threshold intervals, i.e. at or just below MLSS, and you start going over, then you are targeting a different energy system. Same with theLT1 and also lactate balance point.
Getting tested will tell you where it is, but it won’t be the same every single day.
While the resting rate and max HR can be pretty stable over the course of extended periods of time, the present day HR is a proxy for your overall conditioning under the given circumstances. Hydration, change in weight, rest, sleep, fatigue, fueling (fat vs sugars, sugar types), alcohol intake, stress, humidity, temperature, ongoing inflammatory or healing processes in the body, metabolism of pharmaceuticals and more - all of these contribute to a different and variable extent. IMHO, the best way to use HR is to fine tune power zones (esp Z2 where you ride for 1 with a steady HR), training to improve your FTP (reaching a higher power output with HR corresponding to Z2 power, looking at HR vs intensity over longer periods of time (month to a year) and observing progress (hopefully) in your ability to ride at a higher intensity at the same HR. Some of these points are well articulated by Scott McLean (Kinetic Cycling Coaching) who you can find on Youtube.
I didn’t see this suggestion yet: do you already use chest band for HR? If so then ignore this post. If not, then consider one, because the wrist HR measurement can be significantly off.
AeT / Zone 2 based on the speech test as detailed by Iñigo San Millán [1]. I do this regularly on Zone 2 rides. Observe power and heart rate to get a good feeling where AeT occurs. For longer rides of 2h+ my average power will end up about 10% below AeT. I try to keep all efforts during such a ride below AeT.
Sweet spot / Threshold based on FTP obtained by a ramp test, irregularly confirmed through Kolie Moore’s baseline FTP test protocol [2].
VO2max work, ideally you should go by feel, but since we’re all ERG mode addicted, I use 85% of 2.5-minute max from the ramp test for 4 minute intervals (e.g. 6x4’) [3]. Adjust slightly lower for longer intervals. You want to be able to barely finish the final interval.
Micro intervals (e.g. 30/15s), ideally by feel, second-best option at about 5-minute max power. [4]
I realize this is a heart rate discussion, but it is difficult to do anything above long threshold intervals by heart rate alone. For VO2max work, the best bet is to go by RPE anyway, so you’re not missing out necessarily by not having a power meter.
Thanks, @DavidU.
Based on Garmin’s running lactate threshold test defined zones and Iñigo’s definition (talk test), I think I’ve found the correct zones for me.
[4] A Zone 2 ride with a short interval finish seems to be a good way to finish a session.
What’s the general opinion about normal people doing a lactate lab test (to correctly define zones - especially Zone 2)? Is this considered too hard core? I’ll add one of my old posts on the forum regarding my constant battle of the “correct” approach to training (I run and ride):
I’m caught in the rhetoric of the pros, but it’s really thought to go slow the two times I go for a ride in a week. Constantly battling between relaxing and going for it. As an amateur I’m looking to improve my health, I understand the benefits of Z2 for endurance in the long run, but I’m struggling between “training” and having fun at being healthy.
During the winter, when on a trainer, I was doing a lot of Z2 as it is easier in a more controlled environment … but now, when I’m outside, everything changes.
Oh, well … the curse of feeling the need to optimize everything …
It’s really strange because I’m feeling really good - I would understand if I would feel a little off … so interesting.
