AW4 - HIIT calorie count way too low???!!

Discussion in 'Apple Watch' started by jon08, Nov 29, 2018.

  1. jon08, Nov 29, 2018
    Last edited: Nov 29, 2018

    jon08 macrumors 68000

    Nov 14, 2008
    On S3 usually I'd burn 450-530 ACTIVE kcal during a 45-50 min HIIT exercise, with avg. heart rate ranging between 136-142.

    Then I bought S4 and the first time I used it I got similar results as with S3.

    However, then I decided to reset calibration data and recalibrate the new watch, because, well it's a new watch so I wanted to do the proper calibration. (I did two 20-min outdoor walks in Workout out in the open as suggested by Apple to calibrate the watch).

    After that, the next time I did similar HIIT exercise as before the watch tracked ONLY 167 ACTIVE kcal (!!) in 50 mins. How can that be possible? This is way too low. Heart rate was tracked alright, no gaps. Avg. heart rate 133.

    Today was the 2nd time after resetting watch calibration and the results after a similar HIIT training were slightly better: it showed 296 ACTIVE kcal burned. Avg. heart rate 140.

    However, this is still way less than before I reset the calibration when it logged 450-530 ACTIVE kcal during the training.

    Could it be that the watch is still in the process of "learning" and that after a couple more trainings it will display the kcal correctly again? Please advise.

    PS: for the record, my personal metrics in Health app are up-to-date.
  2. Imsuperjp macrumors 6502

    Apr 9, 2010
    Not knowing your age or weight, I would say the new numbers are more accurate. Average heart rate of 140 is not very high.
  3. jon08 thread starter macrumors 68000

    Nov 14, 2008
    Early 30’s and 145lbs. :)
  4. jon08 thread starter macrumors 68000

    Nov 14, 2008
    Ok, looks like the watch is adjusting to my body. Did another HIIT exercise today and the calorie count was already much better now: 442 ACTIVE kcal in 47 mins...
  5. ftaok macrumors 603


    Jan 23, 2002
    East Coast
    Based on what I've seen on various charts, I would guesstimate an honest HIIT workout to come in at 8.0 MET.

    For a 145 lb person and a 50 minute workout, the formulas suggest a burn of 460 kcal. Not sure if that includes the resting calories or not, but it's in the ballpark of what your S3 used to register and what your S4 is doing currently.
  6. jon08 thread starter macrumors 68000

    Nov 14, 2008
    Thanks for your input. Sounds quite close to what I got today! I’m curious what I’ll be getting next time and I’ll post the result here.

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5 November 29, 2018