The marker movement is smooth now. It finds the curve with the lowest interpolated HR for the watts at the marker. Then it interpolates power for all the other curves at that HR. It still gives some strange numbers if you have an anomaly like you do (high power with very low HR) but mostly that happens on the less interesting “close to or above threshold” part of the curves.
Absolutely love it!!! Also it is quite nice how clearly you can see your threshold with it. Will be eagerly waiting to see how this develops.
Also an idea for filtering noise at high power and Hr (way above LTHR): set it up so that the graph requires a positive slope all the time to remove non-existent drops.
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Again an excellent tool ! 
I’ll compare those numbers with outdoors vs indoors. I know that I usually have almost 10 more bpm when I do my workouts on the HT.
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Really helpful and cool. As someone already mentioned, it needs a selection for activity type. At least to filter out or deselect indoor trainer rides (which I always do without fan and even with a fan would lead to higher heart frequencies than the same effort outside).
But probably you already have that on your list or it would be a feature of the coming customizing options of this page.
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Some more thoughts:
- why is the horizontal axis watts and the vertical HR? It maybe is just me, but my intuition would do it the other way round.
- maybe it would be useful to have the page remember the date ranges you set. For example, if I set 2019 vs 2020, it gets lost every time I leave and revisit the page.
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Hello David, I don’t understand well for what duration of power you get the HR
because for sure if I stay for 3 minutes or 10 minutes at 250 W I do not get the same HR at the end
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I think that’s a good point. For the higher intensities I find the chart is a bit optimistic (or shows slightly lower HR). Maybe a way to avoid this is only allowing 1minute or x-minute samples of steady HR/PWR to be charted?
For me it seems that ranges that I pedal at for a long time are best represented in the graph.
Todays Plan has something similar with power on the X-axis so thats why I built mine that way. It should remember the dates between pages until you reload the app. But I might change it to store those on the server like other settings.
@nfkb The lag adjusted power vs HR data for each moving minute of each ride (as shown on the ride decoupling charts) is bucketed into 5w buckets (e.g. 220w, 142bpm, 20 minutes). The curve for a time period is the average of these buckets for all rides weighted by the number of minutes in the bucket. So anomalies mostly get smoothed out.
For watts a bit under threshold you should have a linear relationship between power and HR which is shown quite clearly on the curves. Once you go over threshold your HR climbs the longer you continue until you blow up.
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I have implemented both of these and will deploy Sat AM (GMT+2).
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This is awesome 
Apparently the channel for running power is off. Will there be something similar for running like pace vs HR? Or running power vs HR 
?
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I wonder if this linear relationship can be used to estimate FTP? The point where the linear relationship ends is your FTP. Almost correct for me 
Maybe garmin is doing something like that.
If the line is steeper after training, I find the training effective. If it is less steep, it suggests that you rest and recuperate.
The do something similar to get VO2 max and you can estimate FTP from that so quite likely.
Thanks for this David! Is there any way to change colors on the lines? I’m red/green color blind so it’s pretty difficult for me to tell which season is which right now.
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This is a great addition to intervals.icu!
However, as @Kosio_Varbenov already mentioned I also think that it would be more logical to have heart rate on the x-axis.
This is already given in its name: power vs heart rate. So power is the dependent variable which is usually shown on the y-axis.
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I was a bit worried about that. I will add an option to choose colour palettes for these charts.
I have swapped out the default palette for one that is supposedly colour blind friendly (all 3 sorts) based on this post: https://davidmathlogic.com/colorblind/
Wow, that was fast. Thank you David! This is so much easier for me to read.
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Cool stuff. Since it is HR Data the Indoor/ Outdoor part seems important. Cooling is so different and plays a factor to HR I guess. Now it would be cool to compare Ride vs Ride Vs Ride like this, you can set up a reference ride 2h Base ride for example do it every 6 weeks for example and compare them over time. Or you can do a Ride where you go in all Zones for a reasonable amount of time and do the same comparison over time. That would be so cool to have.
But for now, I have to load some more TSS to finish the week
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Hi David,
This is an amazing tool you’ve created!
The popup is great, it shows the data of interest but the graph could be better.
I have one question and two suggestions that i hope you’ll consider.
Question:
When this tool samples our data, what period of time must pass for a Power/HR correlation to be valid?
I am considering adding a very slow ramp up test every quarter to access stroke volume changes.
Do I need to ramp up slow enough that I spend 60s at each bpm or is 10-20s enough time?
Suggestion 1:
In my mind, it makes more sense to display output (wattage) on the y axis, given an input (HR) on the x axis. I think most users would want to increase power at a given HR rather than lowering HR at a given power. Please correct me if I’m wrong, I image professionals may prefer efficiency (lower HR) as the performance metric because they have already reached their peak muscularity at race weight (w/kg).
ie. tracking improvements in stroke volume is measured with a static heart rate therefore wattage is the only interest, as shown in the popup. Vertical increases make more sense than a shift to the right (appears lower).
Suggestion 2:
Adding a cadence filter to the tool would be hugely beneficial for users that spend a season with/without torque intervals. High cadence is metabolically taxing vs muscular loading of low cadence work, so low cadence / high torque intervals will have a huge impact on comparisons.
eg. User cycling @ 60% FTP alternates cadence every 5 mins (50,75,90). Same fitness and stroke volume but different metabolic cost. HR may be 122bpm, 126bpm, 132bpm.
Great point. I think there is value in the current configuration but less so for aspiring / building cyclists.
Keep this one and add ‘HR vs power’ for the next update.
Great work David!