That’s because the data used for these is ‘cleaned’. Using all available data would yield a chaotic chart. More here:
There is a new top level menu item for comparing time periods and athletes. It currently only shows power vs heart rate but I intend to add more in future including custom charts (like on the fitness page).
The power vs HR chart shows changes in fitness very clearly. As you get fitter your curve will move to the right (more power for the same HR).
[Screen Shot 2020-10-01 at 06.53.38]
The points are derived from the HR lag adjusted data shown on the decoupling charts on the activity HR page. …
That activity has a lot of broken HR data towards the end. If you Actions → Settings you can tick the ignore HR box and it will be left out of the compare data set (I just did that now).
[Screen Shot 2022-04-24 at 07.49.56]
Intervals.icu computes power vs HR data by breaking the activity into 1 minute buckets with average power, HR (adjusted for lag) and cadence for each. Buckets with stopped time and other dodgyness are discarded. This is stored in 5w increments. So for 200-204w your avg HR …
And yes, default charts can’t be changed in colour. They use a default colour palette that is adapted for colour-blind people. That is a limitation at this moment.