Help for writing an app (running zones using Karvonnen method)

Waow, it works great. It's reactive, looks nice and works as expected ! Thanks to all of you, you made my day and year, because I'll be using this app two to four times a week. I hope others will also get benefits out of it. I looked at the code, you did a great job at making this work efficiently. I can't decypher it all, but most of it makes sense, or at least I can guess what it means. It would have required a year of fiddling before I approach something that barely works.
I went for 1 hour run, and the battery handled it, but it may have a sligthly higher toll on the energy draw (compared to the run app).
I think anyone who tried run+ will agree: swiping between both parts of the app with a single direction swipe impacts negatively the UX.
What more ? Bucket list...
At the end of the race, I'm patient enough to go back home and check all the details, but it's only because I have no choice, otherwise, I'd be delighted to see the run stats, namely the percentage of time spent in each Karvonnen zone, average HR, distance, time, average pace, ...