I read on a coaching blog that if you do two sequential workouts at the same power output and you see your average heart rate fall in both workouts, then you can up the power during the next workout work intervals by 1-2% and continue.
I have also read that when doing a workout indoors, you will expect to have an increasing heart rate due to relative lack of cooling vs. outdoors, so the decoupling measurement will be thrown off a little bit by that.
Cooling is not an issue for me. 3 fans and cold air from outside via a window allow me to keep very comfortable temps. That is especially so when I am doing the low intensity workouts that donāt lead to heat from high power output.
Thatās interesting about the repeat workouts. Still a bit tricky with HR variability. I know I introduced some changes between those via hydration variants at the least.
Hereās a link to a spreadsheet I created to track my heartrate vs. power during workouts so that I could determine if I was ready to move up to a higher work effort at the next workout or if I should dial it back because my heart rate was not improving (getting lower) at the same power output from workout to workout (overtraining??). Dropbox - polarized workouts HR.xlsx - Simplify your life
I noticed the bsx insight info on your sheet as well and wondering if you are still using their log in and test or just using the raw data via a gps unit? I havenāt used mine since July and it was my understanding they were stopping support in August.
The interesting thing about heart rate is that Iāve heard it argued both ways:
I havenāt used my BSX since the beginning of the year, when it failed to connect to their servers. One of my friends says that his BSX is still able to connect. I am looking at HUMON, Moxy ($$), and other replacements to help quantify my workouts better.
@steveh67 I had the same issue at one point last winter and had assumed they prematurely stopped supporting it but then it seemed to start working when I tried it again. I have stated looking into those as well and havenāt seen much information on the Humon and the moxy just seems to be a hassle with how it needs to be used. I used to use the bsx insight for determine ftp as I liked the simplicity and lack of stress of the step test involved but havenāt used it that way since TR implemented their step test.
It would be interesting for you to wear your BSX and try the TR ramp test to see if where how the blood oxygen levels map out vs. the different work levels.
Both of these are true.
Iāve started using HRV4Training which as been helpful in terms of adding another vector to calibrate HR data on, and Iāve found it to be pretty useful and quite accurate (it matched exactly when I got sick recently and correlates really well with harder efforts)
@stevemz I have thought this very thing and plan to try it out next ramp test in three weeks.
I have been using elite hrv and have three and a half years of data and definitely find that hrv can be more predictable than hr for predicting impending illness. I have not always adhered to the āreadinessā feature unless it has been in the red for more than a few days.
Greatā¦ now I gotta learn all about HRV???
Thanks guys 
I started using HRV4training a couple of weeks ago and Iāve still got some learning to do but at minimum itās very interesting.
What would the difference be between something like HRV4training and a Garmin Fenix 5/5 Plus? Garmin offers 24x7 āstressā measurement and graphing using HRV data. I imagine that HRV4t has better/more in-depth analysis of that data, but are there no useful insights to be gleaned from an HRM that many of us already wear 24x7?
Iāve seen that also. RMSSD score drops by half after a big, intense ride.
And gradually rises with each day of rest.
However sometimes does not vary as much as I think it should based on how I feel.
I need more time with it to fully understand how to interpret it and use the data.
@mcneese.chad Saw this Aerobic Coupling article posted in another thread, its a much easier read than my previous link:
https://gaffneycyclingcoaching.com/2016/03/16/are-you-ready-for-the-build-phase-of-training-aerobic-coupling/
And here is a good example of aerobic decoupling (with annotations):
A little backstory and no I donāt work for the CA tourism department LOLā¦ Earlier this year in mid January we were having a dry winter and I ended week 5 of SSB1 high volume with a group ride on Mosquito Ridge. It starts in Foresthill with a 9 mile descent, followed by an 18 mile climb at which point you can see the top of Squaw Valley resort (with option to continue to French Meadows reservoir). Its a truly awesome climb if you ever get out this way, here is the Strava segment for the HC climb: Col du Mosquito Ridge | Strava Ride Segment in Foresthill, CA
Back to the aerobic coupling topicā¦ On the 18 mile climb I stopped twice, once to fix a flat, and once to refuel before my final 10 mile push. My climbing style, developed before buying a power meter, is to pick a HR target based on the length of the ride. You can see I pretty much stuck with my target and have a nice flat HR line. My power on the other hand declined, partly because I live at elevation 60 feet and the top of the climb was over 5800 feet. Instead of seeing two parallel lines (no decoupling), you can clearly see them diverge (decoupling).
Hope that helps, along with the far better link about aerobic coupling and how to estimate.
Updated OP with my 2nd Work week.
I see that for your Z3 rides, youāre choosing rides with VO2 max intervals at about 110% FTP. I did huffaker yesterday which has intervals ranging from 110-120%. I found it to be very tough (especially the 2nd 120% interval) - almost fall-off-the-bike tough. 
Curious - any reason why youāve picked workouts with 110% instead is some of the higher ones? The IF is about the same, as the 110% workouts have more intervals, but wondering if thereās a reason youāve gravitated towards the 110% ones?
I can handle more minutes at the 105-115% of FTP range with full completion of the intervals, and I think that is better.
I did tonights which was similar to last Tuesday, but was 10 efforts (instead of 7) I had to take backpedals in the last 3 breaks, but i nailed all the work intervals, so Iām taking that as a win. I feel getting that time high and consistent is more important than being at the absolute top of VO2 Max.
Yeah, Iām 45 and I find the higher VO2 max intervals hard also. For my next Z3 workout Iāll give the 110% intervals a shot.
I think coach Chad has commented on a post recently that if you do enough of the 110% intervals, you end up at VO2 max anyway.
Judging by my HR, respiration, and the feeling that I didnāt think I could handle another one when I finished eachā¦ I think I was working hard enough for long enough to drive some adaptations.
Iām excited to hear what you think of the lower percentage efforts. Good luck. They are still work when you get enough time, but more manageable for sure.
