Hi there! My use case is cycling training+racing mostly at 2500m / 8500ft with some training+racing at other altitudes including sea level.
The rough difference in FTP power for me in raw numbers is about 40W - maybe 250W at altitude, maybe 290W at sea level. This is expected based on literature and I’m able to see W:alt in my activity charts which works very well for me per-activity
I was playing more with season long fitness charts to look at 2023 and see how I progressed, in order to plan out 2024 and I realized that while I know when I was at sea level and I’m able to mentally adjust the fitness charts, it would be much better if I was able to alter the W basis of all charts to W:alt (acclimatized)
Without it is hard to determine the trend for the second half of the season as I had 3 different periods at sea level at exactly the time my peak fitness was supposed to be happening…with 6 different peaks on the graph. But was my fitness really better? Hard to say!
Thanks for your consideration