Hello TRoad,
i did a lot of Sweetspot Torque Training and as an sideeffect my maximal heart rate went down from 191 to 179 over the course of a few months.
I’m really interested in the why.
Is it maybe cause of muscle damage & fatigue? Or can it also be by reduced glycolosis by muscle fiber changes as a result of the training and therefore reduced abilite to use the full amount of aerobic & glycolytic capacities?
Has somebody expierenced somebody similar?
J.
Have you actually had true, maximal efforts in your riding and training recently that push you to your true max effort and heart rate?
Are those comparable to efforts in the past where you saw that 191bpm HR?
Yep, i did the same ramp protocol more then once to confirm it. Max Power Output at the ramp is also slightly decreased.
Fueling is good, looots of carbs.
I also measured lactate levels after the effort, they are very similar so it seems it is not caused by fatigue / katacholamine supression. Or the lactate is coming from massive protein breakdown but then i doubt i could reach such high values (~15 mmol/L at exhaustion).
Any ideas?
Its hard to say @JasonErbgut the data could also mean you are getting fitter so efforts that caused you to max out at 191bpm are now causing you to reach 179bpm and you’ve got another 6-7% before you max out.
Yep i understand what you mean and that would be great but the problem is i can’t use the another 6-7%, i’m just maxing out at lower HR but with similar, even slightly decreased power but at same max lac values.
And i don’t know why 
It feels like i don’t have access to this “last punch” anymore.
I feel the same sometimes but just when I’m thinking that I’m too old and slow that extra bit comes forward with the correct motivation. HR is such a fckle thing sometimes 
You may have just solved the mysterious mystery to sweet spot training.
You put in a solid amount of time to low cadence consistent sweet spot training.
You say you did a ramp test to try and get your HR up higher but didn’t really work out so far.
Maybe now at this point focus on a hand full of workouts where you concentrate on high power, high cadence short hard bursts to really stretch out the legs to see if it opens you back up to that extra 6 percent of power you could be holding onto.
The we can put to rest the ( this vs that ) training debates and realize it could be a little bit of everything is needed to maximize our gains.
If that doesn’t work, then its back to the debates…
Has anyone asked what your are measuring your HR with, then and now, the conditions you tested in and and how many times you tested it?
To your basic question of “have I broken my heart with training” the answer is no.
As you know reduction of max heart rate is often associated with fatigue from a high training load. Conceptually I think of it as if your heart muscle is tired - but that is my concept and I don’t know if there is science to support it.
Lactate accumulation in the blood is a result of events occurring in your leg muscles. Assuming enough oxygen is arriving at the muscle for a particular work load, it stands to reason that blood lactate accumulation would be the same, regardless of heart rate. For example if you start dehydrating, your heart rate will increase because blood oxygen levels drop as plasma volume is reduced, the net result (higher HR, lower oxygen in blood) is the same amount of oxygen delivered to muscles. Not sure if this is accurate, its a thought experiment.
A lot of tempo/SS work, without any top-end work, can lead to a loss of top-end “punch.”
I’m an engineer with no real background in exercise physiology.
I experienced something similar. My findings: inadequate rest.
For months (essentially, all of 2021), I was convinced I was getting ‘fitter’, as over time, my maximal efforts yielded substantially lesser and lesser max HR targets. Each week consisted of 700-1000 TSS, and was a mix of endurance, threshold, and ‘recovery’ days. I say ‘recovery’ sparingly because it clearly wasn’t a proper recovery ride (IF >.70 lol…) …
My max HR for reference is 192, though for efforts I would consider ‘max’ during that period of time, I was plateauing at 175, and this further degraded to the high 160’s by the time I realized the error in my ways.
With 2 full days of rest (However you measure this; low whoop strain/high recovery, HRV, no exercise, being a literal potato etc.), I can get my HR back to its peak, and QUICKLY. Heart rate recovery is also replenished, and I now supplement that to contribute to my understanding of strain and recovery (i.e., low 20’s on a hard ride for me, signal time to rest. High 50’s signals I’m adapting well to the strain i’m enduring and recovering adequately).
My 2c, but a worthwhile experiment that yielded me a lot more success in 2022 than I could have wished for.
well that was not my question, you got it wrong. maybe you can help understand why it is reacting like this?
Hey Jasride, thx for your input.
Actually after the testing after the sst torque block when i noticed the drop i already did a block of short high intense sprint training and retested with the same protocol after it but with the same lower max heart rate result.
Maybe i really just need a big break. Hm, i just want to be sure before i take it that i’m on the right path and not missing out.
2 days off helped you already? I ve taken 4 off followed by an easy week & retested then but still the same lower max heart rate result 
How is your sleep? How is your motivation and morning fatigue? Any changes in resting HR? How many rest days are you taking per week and how often are you taking a rest week? What has your weekly ride time/tss been over the past month versus the past year?
Seems like a big shift in max HR, certainly overtraining would seem to be the most likely cause. Any new medications? Always possible that that could be limiting your HR.
I should clarify- 2 days is roughly my ‘recovery’ benchmark now that i’ve fully recovered from overtraining, and inadequate rest. It took a few weeks, and a 35 ctl bump for me to rebaseline to a point I could begin ramping myself back up. tl;dr, I overtrained.
One other input. I had a Garmin HRM that I used for many year. All through 2021 my HR was getting lower and lower. I just thought I was getting older and or fitter.
However after comparing my ramp test data from 2020 to 2021 I became suspicious that the HRM was faulty. So I replaced it, and BAM, all my HR data was similar to 2020. YMMV
Faulty measurements aside, it could be that your months of sweet spot training converted some of your high-power fast twitch fibres to slow twitch fibres. That means that you lost a bit of top-end power, and because you don’t have that power, you can’t reach the HR you need for that power.
Okay we’re on different pages here - you’ll get good advice from the other posters.
Pretty certain it has not, especially over such a short time period and by so much. The only way I can see that happening is due to a medical condition. It is much more likely that you just havent been able to, for whatever reason push hard enough to hit your HRmax
+1 for fatigue or illness.
Rule this out or another reason you cant push, I’d get a medical checkup.
Personally I find this is a sure fire sign that I need a proper recovery week - I usually expect to see high 180s/low 190s in maximal efforts but if I am fatigued I can struggle to get it past mid 170s.
Try a proper recovery week and see if that helps - if it is due to overreach, then you may actually find a significant bump in fitness afterwards.