How do you deal with cardiovascular efficiency?

[andres42]

At this point I feel I am safe to say my body has become cardiovascular efficient. I do cardio quite often and my active HR and resting HR has lowered but since logging exercises on Fitbit relies so heavily on HR for calorie burn and Fitbit perceives what I’m doing as less difficult than what is happening, what is the best way to go about fixing this?

Should I manually add extra time to workouts? Change my body weight in the app to a slightly higher amount? What do you guys think?

[alexthecat]

@andres42 your Fitbit is demonstrating that you're expending less effort to do the same workouts. It's great that you've adapted to your current routine! Now is a good time to switch things up by increasing intensity or duration or by trying a new form of cardio. 

[YachatsMike]

I am seeing that in my own body.  I do cardio exercises that according to the apparatus measures (calories, Watts, etc.) are the same but my heart rate tends to be slower than it used to be.  Because of that, the aerobic measures (AZM, CL) are difficult to maintain.  What I have to remind myself is that all these metrics are indicators of my basic physical condition and that metrics are not the end in themselves.  The goal is a healthy physical condition.  If I'm healthy and I'm not preparing for some competition, then I can note the change and move on.  If I want to push myself harder to improve my metrics, I can, but if I just want to maintain, then I should set my expectation for lower values.