Improve Cardio load (TRIMP) accuracy

[maxperron]

I train consistently and understand load metrics like TSS, TRIMP, etc. Tried Fitbit's new cardio load feature but it’s off. Example: I tracked a TrainerRoad session with HR only (spinning activity). Fitbit gave a cardio load of 19, while intervals.icu showed a TRIMP of 136. This feature feels unreliable in its current state.

[FourFourTwo]

The Pixel watch 3 is arguably the most accurate optical HR tracker but the Fitbit app is terrible. 

After numerous spinning workouts where Fitbit gave me a cardio load of 0, I started sending my HR data during workouts to Polar Flow instead.

I now get a proper cardio load, easy to read HR data and reliable tracking of my progression. 

Until they fix things (if they ever do), my recommendation is to use the watch but ditch the app.

[shane1717]

spinning cardio load is way off, burn more calories, vigorous heart rate almost the whole time, cardio load should have been higher than the circuit training session, they need to fix

[rockmaninoff]

Agreed. I have Fitbit premium from buying a pixel watch but there is no way I'm going to keep it with such a simple feature being so far off. 30 min power zone with a peloton strive score of 60 and cardio load in fitbit is zero. Cardio load is useless for me if it's not reporting data correctly.

[jimjab]

Agree with the previous posters - cardio load calculations are BROKEN for indoor cycling.  I get HALF the cardio load 'points' from an intense hour on the stationary bike than I do from 15 minutes of walking afterwards.  It's... ridiculous.  So much that it has led all of the people posting here to seek out an answer.  Please, for the love of god, fix this so I don't have to jiggle my wrist while riding my bike indoors to get 'cardio load' to count.  It undermines the whole program.

[hovdeo]

got same issues as many have already mentioned. currently , i cannot use cardio load for anything reasonable the way it is working today. nice gimmick and barely that, at best.

did 2 hrs on the indoor bike trainer this morning, 5x10' threshold intervals which is a fairly hard session. 188 active zone minutes fitbit says but just 80 on cardio load. avg HR 130 (charge 5) vs 138bpm with garmin strap. max HR 161 (charge 5) vs 165 with garmin strap. TSS 157 on trainingpeaks

when i compare to an older running session - 1 hr, avg HR garmin strap 137, max 168bpm, charge avg 157bpm (?????) peak 175bpm (not a chance, max is about 174 - 176), 122 active zone mins, and 225 cardio load, similar readiness as today

gym sessions, 75 min, avg HR 115 - 120bpm with peak of 140 - 145bpm - cardio load will come in at 80 - 120 go figure

is the cardio load an attempt to create a fitbit-pixel version Training Stress Score (TSS) at TrainingPeaks with a slight adjustment for readiness score? is hand wrist based HR readers too inaccurate to do what they try to achieve with cardio load?

now it seems to be an interesting idea but hardware and algorithms do not seem to be able to deliver.

[AranelS]

The algorithm also appears not to have heard of a menstrual cycle, which is not helping.

Resting heart rate rises at a certain point in the cycle, and then decreases back to normal, and this seems to totally break the recommendations. It's not actually a change compared to last week, the baseline is just moving in a completely predictable way.

[Synthdragon]

It doesn't seem to track correctly for me. I did an intense workout this morning and it gave me ZERO cardio load. But when I go for a short walk I get cardio load points? It makes no sense.

I paid this much money for a Google pixel smartwatch for it to only not work properly? I thought it was just me but apparently very common.

[kieleth]

After checking Reddit I arrived here as many others facing the same issue:

go for a walk: cardio load spikes to 40’s 50’s, I haven’t broken a sweat

Do a strenuous VO2 increase session on my static during 60 minutes: cardio loads bumps 8 points. 

I happen to have worked developing activity algorithms with activity data in the past, and this to me is a clear bug in some part of the modeling or heuristics used to perform and tweak the cardio load calculation. My theory is that while cycling Fitbit does not switch to “being active “ mode and is somehow filtering any HR activity towards the cardio load.

It’s a pity this feature was released without proper testing in each of the activities Fitbit allows, even more pity is that this has been going on for months and nobody is fixing it. Usual Fitbit not taking responsibility for their bugs.

[cravenjack01]

That’s a huge discrepancy! Hopefully, Fitbit fine-tunes the algorithm to better reflect actual effort Window Coverings Conroe, especially for structured workouts.

[martinbzz99]

I am probably just another voice amongst many. However - what is the point of cardio load (if it works at all…) when it is evidently so underdeveloped. It swings wildly between telling me that I am over-training and the next day telling me that I need to achieve a load in a range of 210 - 290, which is pretty hard to do without running a half-marathon every other day…. I am pretty fit but I am 62 with metal hips… It all feels very much in need of proper development and as having been rushed out well before properly tested.

[Brassy]

Cardio Load appears to still be broken. It doesn’t have any useful explanation for newbies and the notifications about under and over training are inconsistent with the data it does provide. If I increase my cardio load I start getting undertraining warnings and if I slack off for a couple days I get warnings that I’m overtraining. If it isn’t going to make sense, it might be better to remove it so it’s not causing frustration and confusion. I like the concept, but trying to use cardio load is just so frustrating.