What does cardio load mean and what does it want with me?

[sikhanegi]

I work out 4/5 times a week, 1 hour Muay Thai and 1 hour weight training per day. And STILL, my fitbit inspire 3 is telling me my cardio load is low, I am "only maintaining" despite my goal to "improve fitness", and that I should increase my exercise. I don't get it, this is already the max a reasonable person with work and social life can do in my opinion, personally speaking. Maybe I am not understanding the metric, can someone enlighten me? What else does it want from me??

[Gr4ndp4]

Hi, @sikhanegi welcome. You may find this article of interest What are cardio load and target load? - Fitbit Help Center If after you've considered this and the links, and are still stuck, please post here again.

Cheers

[amymurray122]

Cardio load is a fairly useless stat for most people. This comment from a post about cardio load might help explain it better:

i asked Gemini AI why the Fitbit cardio load is illogical and unreliable and got a detailed response. Basically the TRIMP algorithm doesn't work well for people like me who concentrate on strength and resistance training at the gym. This is true as I can do a 90 minute weight session and  earn a handful of "points". Another time I can do what feels like the same session and earn far more points. Sometimes I can earn more CL doing the supermarket shop than 90 minutes of heavy lifting.

Google's own Gemini AI recommends ignoring CL in favour of Active Zone Minutes.

The summary section of the Gemini response is below. It's a shame Google Fitbit developers don't consult Google AI!

Summary

​The feature is currently biased heavily toward endurance runners/cyclists and struggles to quantify the fitness generated by the gym/mixed-fitness lifestyle you lead in Cambridge.

​My recommendation:

Ignore the "Cardio Target" dial entirely. For gym work, Active Zone Minutes remains a more reliable metric because it simply counts "time spent doing work" rather than trying to calculate a complex (and often flawed) physiological load score.

[Poonguzhali]

You’re not doing anything wrong : cardio load is just Fitbit’s algorithm trying to quantify training stress, not your actual effort or dedication. It mainly looks at heart rate zones, duration and recovery trends not how hard your workouts feel. If your body has adapted to your routine, the watch may label it as maintaining even though you’re training consistently and intensely. That doesnot mean you’re not fit or improving, it just means your body is efficient. Real life fitness isn’t always reflected perfectly by an algorithm. If you feel strong, energized or progressing, you’re doing great.

[YachatsMike]

Cardio Load is an aerobic statistic.  It's designed to measure intensity by tracking heart rate.  Most weight lifting routines are mainly anaerobic.  They use anaerobic power and don't really raise your heart rate that much given the effort you put in.

If you wanted to use TRIMP methodology to track weights you would use a different measure like pounds x reps.  (You might have to track each exercise separately to get the  most accurate number)  To get the equivalent of a target load you would have to you would track pounds x reps and divide the average pounds x reps over the last 7 days over the average of the last 28 days.  You would then choose your next workout to keep the ratio 1 or less to maintain or over 1 but less than 1.1 to improve.  (1.1 keeps your weight delta at 10% to prevent injury)

The bottom line is that Cardio Load works really well for aerobic exercise but for resistance exercise, not so much.

[YachatsMike]

Zone Minutes are no better than Cardio Load for measuring gym exercise.  It's still using a cardio measure to track non-cardio exercise.  The way to increase your score would be to increase the speed of your reps so that your heart rate rises.  That's a prescription for injury in the weight room.