Accurately tracking exercises like cycling

smrybacki
smrybacki Posts: 78 Member
in Fitness and Exercise
I have a FitBit Ionic that does a pretty fair job of tracking cycle rides (and other stuff like hikes, walks, etc) with it's built-in GPS. In short, it is fine for my meager needs as an older guy trying to get/stay in good condition.

Of course the the bigger factor is diet, and MFP does a great job of tracking what I eat. I am on a trial of Strava based on a friend's suggestion, but when I hook all of these things up with one another, the exercise calories added back seem way high to me.

Would I be best off simply synching FitBit and MFP, tracking my exercises in Fitbit along with my steps and letting MFP "do the math" and give me a proper calorie target? I also assume that Strava is a bridge too far and screws this whole process up by double tracking?

Any help would be appreciated.

Replies

  • NorthCascades
    NorthCascades Posts: 10,970 Member
    Turn your Fitbit off on the bike and use Strava instead.
  • nanastaci2020
    nanastaci2020 Posts: 1,072 Member
    You can log activity @ the Fitbit app. If you use Strava for calories burned, and log that in Fitbit, it should right everything. Because Fitbit would replace its own estimation with the data from Strava.
  • zebasschick
    zebasschick Posts: 910 Member
    i just log my exercises direct into my fitness pal. any estimate you get from pretty much any app or device will be an estimate, so just don't eat back all your exercise calories.

    it would be great if there was something that could give us exact calorie burn, but considering that 2 people of the same age, height, weight and gender can have massively different muscle mass and fitness levels, it's not likely to happen. even a heart rate monitor has potential issues.
  • NorthCascades
    NorthCascades Posts: 10,970 Member
    @zebasschick a power meter will give an exact calorie burn for cycling. Or as close as you can get outside a metabolic ward, it can be off by as much as 2.5% in either direction. Definitely a measurement and not an estimate.

    That's not right (ie too expensive) for most people, but for sure it's not a case of everything's a guess and there's no way to know.
  • Machka9
    Machka9 Posts: 24,831 Member
    edited September 2020
    No fitbit just Strava.
  • zebasschick
    zebasschick Posts: 910 Member
    NorthCascades wrote: »
    @zebasschick a power meter will give an exact calorie burn for cycling. Or as close as you can get outside a metabolic ward, it can be off by as much as 2.5% in either direction. Definitely a measurement and not an estimate.

    That's not right (ie too expensive) for most people, but for sure it's not a case of everything's a guess and there's no way to know.


    thanks... i'm reading about them now, can't figure out how they work, but i'll keep reading till i do!
  • NorthCascades
    NorthCascades Posts: 10,970 Member
    Basically it's a thing like in your bathroom scale. You stand on a scale and your weight bends the scale internals, it has a "strain guage" to measure how much it bends, and from that it knows your weight. Power meters use strain guages to measure how much force you're putting in, and they measure how often you're applying force, aka rpms.

    It's been studied extensively, including in metabolic wards, everybody has almost the same metabolic efficiency on a bike. There's about 5% variance from person to person, the way you convert the Joules from a PM to calories puts you in the middle of that range, so +/- about 2.5 %.

    Bikes are a special case.
  • Onedaywriter
    Onedaywriter Posts: 324 Member
    One thing to be careful about.
    When I use Strava I normally do it with my phone in my jersey pocket. For some reason my phone logs some steps when I’m riding (I can’t figure out when but I guess when the motion is close to that of a step).
    For example, the other day I took a 20 mile ride and my phone added about 2500 steps which then got reported to MFP and I was given extra calories for steps.
  • heybales
    heybales Posts: 18,842 Member
    Onedaywriter wrote: »
    One thing to be careful about.
    When I use Strava I normally do it with my phone in my jersey pocket. For some reason my phone logs some steps when I’m riding (I can’t figure out when but I guess when the motion is close to that of a step).
    For example, the other day I took a 20 mile ride and my phone added about 2500 steps which then got reported to MFP and I was given extra calories for steps.

    I'll get 15-20K "steps" with on-body Garmin on 2 hr or longer bike ride.
    Road vibration.
    I've worked out the average cadence for time, it's not your feet.
    I'm thinking I've got some rough roads compared to yours.

    I hope the Strava calorie burn wins out over the steps in whatever app gets that count.
  • Onedaywriter
    Onedaywriter Posts: 324 Member
    Definitely based on the Strava count!! But instead of all the manipulation to remove the steps I just leave the calories associated with the extra steps lower the bike ride time I report to MFP to get the combined calorie count that Strava said. I look at Strava anyway for bike data.
  • heybales
    heybales Posts: 18,842 Member
    If you have Strava sync to Garmin (is that even a thing, never tested?), it'll correctly replace all calories associated with a chunk of time it already had data, leaving the steps since that's not synced in.

    Tested it with MFP. Created workout here, it synced to there, and replaced the calories the VF3 had calculated for the "step" activity - distance was meaningless of course and calorie burn terrible.

    Deleted it and then synced the Garmin FR310XT that had the actual bike stats on it.

    So if you synced Strava to MFP actually, it would create a simple workout of start/duration time and calorie burn.
    And that should sync to Garmin replacing the "step" calculated data, your daily burn would be corrected, and synced back to MFP. In which case no Strava to Garmin sync.
  • persimmonfig
    persimmonfig Posts: 15 Member
    sijomial wrote: »
    One thing to note though is that the Strava calorie amount is a gross calorie estimate and not net calories that you really want if using the MyFitnessPal way of accounting for exercise. But you can get round that limitation by looking at the kilojoules energy output number for your activity and logging that number as calories.

    First I want to say that I think sijomial's advice is really good! And I appreciate the PM check. It's always nice when someone takes the time to share comparison data about device accuracy :)

    I suspect that part of the problem might indeed be the difference between gross calories burned during a ride and net calories burned, accounting for what your body would have used normally anyway. That and the fact that as sijomial points out, your Fitbit probably isn't quite as accurate with regards to how terrain affects your effort on the bike (for example, it might not account as well for the fact that you're slowing down to climb a steep hill as opposed to while cycling on flat terrain). Both of these factors could really add up, especially if you're going on longer rides.

    I'm not a cyclist--I run, lift, and do indoor exercise--but checked this thread out because my partner is and has been having similar questions. But one last note about devices and syncing: I use a Polar chest strap heart rate monitor, which I've set to export to MFP. I've noticed that the calories input to MFP after a run or session are always lower than what is displayed in the Polar apps, and the difference seems to correspond more or less to the amount that I think I would burn at rest through basal metabolism (based on BIA scale estimate, among others). There might also be some other devices that do this for you automatically when they interact with MFP. It's worth checking to see how the numbers that are imported compare with what's displayed in Strava--if they're the same, you will want to adjust downward in MFP.

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