Heart rate decoupling on ride, please analyze. (Photo included)

This was done after a day of construction and mowing the lawn. As you can see my hr kept going up and I got a bit shaky around 1:15. Lowered intensity and finished out the ride. I had Infinit nutrition drink during ride at 80g carbs and 479mg sodium per hour. was it overall fatigue or could be that I’m not conditioned enough yet, just started back cycling 8 weeks ago. Thanks!

Aerobic conditioning takes time, dont expect instant results.

go to Intervals.icu and link it to your strava, it’s a fantastic tool to see CTL, HR decoupling and heaps more.

Aim for 3hrs high zone2 with less than 5% drift.

also just do a full base plan, that’s where you get the aerobic gains from

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Looks like HR drift. Not uncommon if you were doing hard things all day.

I second the use of intervals.icu for easy access to the data. Be careful, because the data is always present for any workout, but it is really only valid for specific workouts in a general Endurance range of effort, and 2 hours or more riding.

Good article to read:

Another older one, that covers how to do the calculation yourself:

If you don’t want to deal with i.cu, you can use my sheet that has the calculations offered, once you query your workout to get the base values: (HR Decoupling tab)


yep! totally agree on the ride length. I only look at hr decoupling for solid 3hr+ high zone 2 rides.

Would you guys suggest keeping with the Z2 workouts at prescribed intensity or lowering intensity as hr starts to decouple?

I got some unexpected drift doing Baxter yesterday but I found out after the workout that my AC was pumping hot air into the room because my wife pressed the remote (hopefully) without knowing.
Heat and humidity in indoor training can cause huge HR drifting in a very short time.
So I would audit your cooling solution before taking conclusions about your fitness.

That’s an open question (with a couple of active threads now) and has people on all sides.

I can try to find some for you to review, but it’s not a simple answer.

Personally I’ve done zone 2 workouts to power during early base (think Traditional Base 1). Within 4-8 weeks I’ve seen decoupling drop to 2-3% (or lower) on 2-hour zone2 and zone3 workouts.

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Couple things for this thread… remember, the right answer is usually “it depends”:

  • Ride it out or lower intensity? Depends on the length of your ride and when the decoupling is taking place. If you’re decoupling at 1:45 of a 2:00 ride, I would ride it out. If it’s 2:00 out of a 4:00 ride, I would lower the intensity.

  • Decoupling is valid for any length of aerobic ride. To say it doesn’t matter on a short ride isn’t accurate. It may not matter for some riders on a 90 min ride if you are already aerobically fit enough to ride that length easily, and decoupling across a 3:00 or 4:00 ride may be more relevant if you’re training for a rolling road race. But that doesn’t apply to everyone. A sprint triathlete or Cat 4 crit racer has enough aerobic fitness when they can ride a 90-min Z2 session with minimal decoupling, and might not need to spend long hours on the bike with minimal decoupling if their goals aren’t inclusive of growing additional durations.

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That makes sense. My races are around 2 hrs so that’s really what I should shoot for.

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Thanks Kurt, wanted to write the same but it was a busy day. Well said.

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Definitely a lot of ‘it depends’ when it comes to training.


HR drift can happen at any time. Sometimes doesn’t matter what you drink or eat.
This morning i was doing great until i didn’t. It was a terrible 30 minute dead march. My HR was great for the first mile (140s) then out of no where it went to 160s. I reduced speed and it just kept climbing.

What im trying to say, a high HR is not necessarily indicative of bad nutrition, or lack of fitness. Maybe it was hotter that day. Maybe you didnt sleep well. Maybe cumulative fatigue. Like you said correctly…it depends.

This is a pretty interesting video from Stephen Seiler on Z2 intensity and HR drift.

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Couldn’t agree more!

I applied the formulas in Golden Cheetah and interestingly I did find a sort of pivot point in my long steady rides where the drift do accelerates.

The funniest thing is that I compared two very steady rides one month apart and that point came more or less around the same time but the second one was 15w above the former which, in my opinion reveals a fitness gain.

I think we should pass that turning point in the long rides to sort of tell the body it needs to adapt for that ride extension for that power target but we should not push it to much because of the cost of recovery if we challenge homeostasis too further down.

I would like to setup a real time metric (that needed to be defined as a moving average) to track this during the long rides. Maybe something like a Garmin IQ field.

Great watch!

I implemented the chart from that video in Intervals.icu for people interested in this stuff (should be everyone!):


Nice. I only figured out what drift aka decoupling was about a month ago (with forum members’ help), and that it actually might tell me something, and just as I’m scratching my head trying to figure out how to picture my own, David’s already gone and done it.

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