Cardiac drift versus power

How would one best test and visualize the impact of steady state power targets on cardiac drift? My thought would be power on x-axis and “time-to-5%” on the y axis. Does the absolute heart rate matter? Naturally this would be different as different steady-state powers are tested.

Welcome, Benjamin.

Sounds like you are talking about Decoupling, which Intervals can derive and graph over the course of a ride. Best derived from data obtained through long (2 hr +) rides at an aerobic pace (Zone 2). Used to measure one’s cardiovascular fitness.

I notice that if I drink sugar water like a hummingbird, I have essentially zero decoupling, even on a 3hr effort recently that was Z3 with some Z4 portions. I only got behind at the very end when I ran out of sugar!

I’m asking about decoupling as a function of power and duration, not just decoupling over the course of a ride. I have already done zone 2 rides out to 10 hours, but I haven’t mapped how decoupling maps to different steady state powers above that intensity.

Decoupling only makes sense for endurance intensities, not the higher ones.

Nah. First off, this says AeT for the average athlete is anywhere from 55-75% of FTP; for me thats already a range of over 70 watts. Then, they say runners have a different range, and as you train, your range changes as well, they say anywhere up to 85%. If you use that range, now I have 100 watts to evaluate this over and still be within “endurance intensity”.

I’m not saying I want to do it in 5x5 min VO2max intervals; I’m already doing 90 minute steady state rides at 85% of FTP. I define endurance intensity as any intensity I can ride for an endurance period (60 minutes to 10 hours?), not a specific wattage or heart rate relative to FTP. This is exactly why I want to evaluate it in my own training across a range.