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Fenix 7s not counting calories while swimming

micheyll
over 2 years ago

I've gone swimming pool swimming twice and both times I had the same issue: the Fenix 7s won't track active calories.

On my first swim it said zero active calories burned, whereas today it says 20 active calories. If I do anything else, be it running or tennis, the calorie tracking works perfectly.

Is this a bug and does anyone happen to know any workaround?

Edit: we've figured this out, thanks to the helpful Garmin community. It's not a bug, but instead me largely overestimating how many calories I should be burning.

  • 0 over 2 years ago in reply to mcbit

    Ah, the 300 calories burned is because I changed it manually. Didn't remember to comment on that, sorry. It showed a total of 54 calories (or something along those lines) before I corrected it by hand. The intervals with only the heart rate are me resting and catching my breath.

  • 0 over 2 years ago in reply to micheyll

    I’ve just checked some of my old swims with Fenix 6 and typicaly it was 300 to 400 calories for 1 kilometer swimming, depends time of swimming, how I measured heart rate (wrist or external sensor).
    I cannot tell you how it might be on my Fenix 7 because didn’t had a ocasion to do swim with it in swimming ppol.

  • 0 over 2 years ago in reply to micheyll

    No intent to offend as I'm just trying to apply a bit of perspective. From what you have said about the blank intervals it looks like you spent less than 50% of the time actually swimming, so really I'm not surprised by the low calorie burn.

    Thrashing around with an elevated heart rate does not guarantee a high calorie burn, you have to develop power to burn calories which is proportional to speed through the water and body weight. As an example if cycle with a cadence of 120 rpm at half the speed at which I normally travel for a cadence of 60 rpm, my heart rate will be through the roof but I will burn significantly less calories as despite the high cadence, the power I'm developing is much less.

  • 0 over 2 years ago in reply to mcbit

    I see no reason to be offended, as this is something I questioned myself as well. However, it's very difficult for me to believe I would burn something like 20-50 calories doing an exercise that leaves me drained for the rest of the day, especially when even a leisurely walk to the nearby store and back burns more. Could be that the watch is just incapable of taking into account how inefficient my current swimming technique actually is, and therefore thinking I barely did anything.

  • +1 over 2 years ago in reply to micheyll

    Don't fall into the trap of trying to compare body stress and tiredness with productivity and calorie burn. If you engage muscle groups in an activity for which they have no significant muscle memory you will become very tired very quickly without a significant calorie burn. Running and walking are obviously activities you are familiar with which do not stress your body in the same way.

    Below is a comparison using this Energy Expenditure In Swimming - Google Sheets calculator. The calculator calculates the energy requirement for the activity and I have added the numbers outlined in red which represents the actually body calorie burn at a typical gross efficiency for swimming of 10%. The send set is using the Garmin output from the recent swim of an acquaintance of mine.

  • 0 over 2 years ago in reply to mcbit

    Alright, you have convinced me. Thank you for putting so much time into this, I do appreciate it. I'm glad the watch doesn't have some unknown bug that cannot be resolved. Now onto the next challenge: how to not overeat after a swim. =)

    This does also explain why I've burned increasingly more calories each time I've swam, even though the first time felt by far the most challenging.