Cardiovascular drift versus decoupling
Cardiovascular drift is simply where your HR raises over time through effort. Decoupling is where you have so much cardiovascular drift that PWR zones and HR zones no longer align.
For instance, on a hot day, you might be cruising in zone 2 watts, but your HR is zone 3 or zone 4 due to environmental factors. Not to mention effects of altitude.
Cardiovascular drift does not necessarily mean decoupling. But both concepts reflect the relationship of exterior stress (watts) versus interior strain (HR).
Why is this important? When decoupled, you’ll have to make the decision given the context of your training as to when to chase watts or lower your HR to reduce the strain.
On this tempo 30-min tempo effort shown in the image below, I definitely decoupled towards the end. While maintaining zone 3 watts, my HR drifted into Zone 4. It certainly wasn't hot out. I'm just in a low-state of fitness.
Something that I track for both myself and clients.
FTP work is pain! But when should you be doing FTP intervals? Are they something you should just throw into your calendar when you feel like it, or should they be part of a dedicated program of progression and developed in the context of your events?