I absolutely love Intervals!

Hey guys,
just did another free trial of Strava and knew after just 10min that it just isn’t for me.
I am doing a lot of training on Zwift and am in the Garmin ecosystem (HR strap, PowerMeter, Fenix 6X).
Intervals just add so much value to my 5-6 workouts every week it’s amazing.
So I’ve decided to subscribe, just to show my appreciation.
I was able to loose 30kg, run my first marathon and get in good shape by getting absolutely hooked on fitness data (like HR/Power-Ratio).
Thank you so much for the amazing work!


Hi Roland,
Great testimony! Can I ask: How do you read and use the HR/Power-Ratio? I find it difficult to do comparisons since the routes are different most of the time. How do you get about it?

Like for instance these two readings:

  • both are from 1.5 hours of riding with the same pacepartner in Zwift.
  • in the one, there is a negative decoupling (indicating that I did better in the second half of the ride, producing more power for less beats) but the power/HR is only 1.71.
  • in the other, there is a negative decoupling but the power/HR is 1.82.

Two questions:

  • what will you read out of these two rides, how to use this metric properly?
  • and why is the power/HR not higher in the first ride since I produced more power for less beats?


Congrats on a nice steady endurance discipline!
Power/HR metric can’t be evaluated from one ride to another because it varies quite a bit. The variation is caused by your state of recovery/stress… You should evaluate a trend over a longer period.
What the charts are telling you, is that you are perfectly capable of handling that intensity for that workout duration and your HR is below AeT (Z1 in the three zone system).
My advice would be to slightly increase the intensity for those endurance rides until you get an average decoupling between 3 and 5%.
This is based on advice by uphillathlete:

Or make the rides longer and determine at what duration you start to decouple if your main intrest is in long events. Both “Power below AeT (in terms of intensity)” and “Endurance below AeT (in terms of duration)” are trainable.
I pay more attention to the last graph because it nicely shows a drift if there is one. In your case there is no drift at all. For a recovery ride, that’s perfect. You might even see a drift with negative decoupling, meaning that you are feeling better while riding low intensity recovery.
For an endurance ride, I like to see a small positive decoupling in the order of roughly 2-3% to inflict adaptation.


Thanks, great reply, really helpful!