Struggling with HR during sweet spot

I’ve been doing some reading on sweet spot training, and it’s made me unsure of what I should be doing. I just finished SSHV1, and started SSHV2 and I want to make sure I get it right. I did the first build with my FTP set at 275, and I would constantly have to lower my power to keep my HR under LT during the intervals. Looking at my HR graphs they slope upwards across every interval. Pretty badly so, like Ill be at 165bpm two minutes into my first 20 minute interval and I’ll be at 185bpm by the end (my LTHR is 187). Then I’ll bump down the power down, but I never bump it down enough because the next interval my HR will slope up, but just at lower power.

I was pretty confident in my FTP assessment (previous 4DP test and some zwift racing), if anything I think I was higher but I know sustained power is a weakness so I went with the lower end of what I thought it probably was. But because I was thinking about making this post and build phase 2 starts out with a ramp test I went ahead and did it so I could have the number on the test that TR recommends (I’m not a fan of ramp tests). I didn’t bury myself all that hard (I probably could have gone 10-15 seconds more at least) and I got 284. For giggles I did the first workout (carillon +2)with those numbers and after finishing the first interval (where by the end I was at LT), I took it out of erg mode and did the last two 20 minute intervals trying to keep my HR just under 180, and I was hovering around 210 watts, so 40+ watts lower that what it called for :frowning:

So my question is, what should I do? Do I keep lowering my FTP until I’m getting through my workouts where I’m not adjusting the power at all and my HR doesn’t decouple at all (or maybe not till just towards the very end). Say its 245 for arguments sake. Or should I start out with say an FTP of 260 but then slowly lower my power over the ride so my HR stays flat, even if I’m ending at say FTP of 230? Or should I be doing something else?

I’m eating a gel every 30 minutes and have a bottle of water and a 200 calorie bottle of tailwind over a ride. I have a recovery drink right after and I get 9-10 hours of sleep a night. So I don’t think its any of that contributing to my struggles, I just suck at sustained power.

First how did you determine your LTHR was 187bpm? What is your cooling setup?


If your problem during sustainable power is HR not legs, definitely check your cooling. Without a fan I could not finish Galena+1 because I was cooking and my HR went into 96÷ of HR max. Only after using two fans my HR stays leveled during long intervals at FTP.


What you are experiencing is typical. TR is sorta geared/implemented to ignore heartrate. If you want to use TR your experience will be better if you do that.

If you want to do sweetspot work you can either hold power constant and deal with an increasing HR over the interval or hold HR constant and deal with a decreasing power over the interval. TR software implicitly follows the former approach.


These things are personal, but that doesn’t sound like sweet spot to me. For instance, I looked at my last Carillon and at the high points HR-wise I was generally 15 beats lower than my estimated LTHR (so for reference around/under 160), and I found it fairly comfortable.

As mentioned, HR will by default drift up a bit throughout the intervals, but if it’s going crazy there are likely three causes (any or all could apply!)

  1. insufficient cooling
  2. insufficient base fitness
  3. FTP set too high

If you have your calendar public, a link might help people give more informed advice but without much to go on that’s my best attempt :slight_smile:


I was thinking the same. Assuming fans then perhaps both 2 and 3? Hard to say without more info.


That’s what The Sufferfest gave as my LTHR after a 4DP test, and it lines up with race data and generally how I feel during rides if I go by HR.

Can’t believe I forgot to mention my cooling setup, I have am 8 inch fan and a lasko blower fan pointed at my front and a 20" box fan pointed at my back. In generally I sweat like a mofo and overheating is always something I have to watch for, but there isn’t any pools of sweat on the floor when im done and I never feel hot.

I think I figured out how to make my calendar public


Not all my training previous to starting TR was imported, so it looks like I had a month off before I started and only a couple months riding before, but that’s not the case. I’ve been riding 5-6 days a week for the last 18ish months, tho I have never done a specific base build so maybe that is part of the problem.

Maybe an aerobic endurance issue? If it is, would refer you to Joe Friel’s advice and try doing 2-4 hour low-intensity rides to build strong aerobic endurance. A month or two of doing that can really help establish aerobic endurance if you don’t have that base.


Thanks for that link. My primary goal is completing the leadville 100 in August. Given that, In your opinion do you think I would be best served by

  1. abandoning SS2 and doing 2-4 hour low intensity rides to build my aerobic endurance for several weeks, then coming back to SS2

  2. swapping out a ride or two a week of the SS2 plan for a 2-4 hour low intensity ride

  3. continue with SS2 but adjust my FTP

If I extend out the training by doing several weeks of low intensity, I wont be able to complete the SS, power build, marathon stack before leadville

thanks for all help

I’d do option two. Do a long steady Zone 2 ride on the weekend.

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Given Leadville is your event, if possible I’d go longer and progressively target 3-6 hour rides on the weekend. For example if you are doing 4 week blocks (e.g. during TR build) then over 3 weekends do a 3 hour ride the first weekend, then 4 hour ride the second weekend, and then a 5 hour ride the third weekend.

For example here is a recent 3 week loading block:

SS2 has 5 loading weeks and 1 adaptation/regeneration/recovery week. Just apply that basic idea of doing longer and longer weekend rides, and be sure and give yourself at least a day of rest after the big weekend ride so that you are ready for more mid-week SS2 over-under/threshold/vo2max work.

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sorry to bump this, just figured I’d post an update for anyone in a similar situation who finds this via a search in the future.

I ended up setting my FTP at 265 and doing all my workouts at that with the aim of not adjusting down during the ride and hopefully having a bit flatter of a HR, and then ditching the planned sunday ride and doing 3-4 hours keeping my heart rate in zone 2. The long rides definitely made a huge impact (and I saw pretty big gains in the amount of decoupling in those rides each week) and I felt like it had a pretty big effect on my ability to hold the sweet spot intervals with less decoupling

I was worried that the lower FTP used might have a negative impact on my overall FTP, but my ramp test after finishing the block was 301 so I actually saw a decent gain.

Thanks for all the help, it was super beneficial to me

I don’t understand the need to keep HR down during prolonged efforts? Isn’t the whole point of exercise to get your HR up? When or how does a good thing become a bad thing?

Well the point of sweet spot as I understand it, is that you can have a high volume of training at that intensity and build muscular endurance because it’s not as hard on your body as threshold work so you don’t need as much recovery…but if your heart rate gets too high, you are effectively doing threshold work and not sweet spot, which defeats the whole point.

I thought intensity was defined by power, not by HR?

I’m training for leadville as well and this is my exact approach. I’m just re-starting SSBHV2 and will do SS rides Tues, Wed, Thurs, with 4-6 hour rides on Saturday. Sunday is a flex day that I mix up a bit depending on how I feel. I followed this approach late last year in SSBHV and my endurance was the best I’ve ever had.

I’ve got Fridays off through early August and I’ve been doing a 4-5 hour Z2 ride on Fridays (in addition to saturdays) the last couple weeks, trying to see how my body handles it. So far it feels pretty good.

No, because you wont improve performance if you keep training at a very high heart rate % of your FTP, on every workout, youd probably end up not being able to get through the workout. I changed from the high volume plan to the low volume one , but my main struggles were with riding at a much higher cadence than Im used to for a long workout, and not being used to erg mode on the trainer. I think he says his base endurance is weak, and I agree that the long steady rides would help, before going for the harder intervals

if your FTP is set correctly then metabolically you are not doing threshold work. You are still doing sweet spot work, working on improvements to muscular endurance (and other things) but with a little more cardiovascular strain. That additional cardio strain may or may not impact your recovery. If it does impact recovery, then time to reassess things.

anyways the original comment was about zone2:

and reasonable people can disagree, I’m strongly in the camp of keeping power in zone2 on aerobic endurance rides (and ignoring HR).

One of the goals of doing long zone2 rides is to improve:

  • the endurance of slow-twitch muscle fibers
  • make type IIa fast-twitch fibers better at doing aerobic work

If you go for say 6 hours at 70% of FTP, as the ride gets longer some slow-twitch fibers will quit and fast-twitch are recruited. Thats when your heart rate increases, because fast-twitch use more oxygen. That increase in a heart rate is a good thing, you are now working on improving aerobic capabilities of fast-twitch muscle fibers. I’m ignoring other reasons heart rate may increase on long rides, to illustrate my point as to why I believe its better to target power on long zone 2 rides. If your heart rate never goes up, it is time to do longer zone 2 rides if you want to improve overall aerobic function of both muscle fiber types.

I think this is a good example of why volume is something that needs to be built up over time, and why folks shouldn’t jump into a TR High Volume plan without a few solid seasons of structured training under his/her belt.

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