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Trekking: Calories calculation without weight of backpack? Why?

Former Member
Former Member over 4 years ago

How much sense does it make to calculate calories during a trekking activity without the possibility to consider the weight of the backpack? Shouldn't be too hard to add a "carried weight" option in future software update. Please add this feature soon, to make a great device even better! Thank you. 

  • 0 over 4 years ago

    Your HR, I suppose, would be correlated with total weight you carrying. 

  • 0 over 4 years ago

    A lot of sense.

    Calories are calculated on the basis of heart rate. Carrying a heavy backpack is harder work than walking the same trail unladen, and this will show up as a higher heart rate. 

  • Former Member
    0 Former Member over 4 years ago in reply to mcalista

    Genuinely curious if you have a source available for this, like did you read Garmin saying that's how they calculate it? I don't understand how calories could be calculated on the basis of heart rate alone. Weight always factors in every calorie burn estimation I've ever seen. Certainly body weight and by extension, carried weight. Heart rate helps that estimate but surely it alone isn't sufficient.

  • +1 over 4 years ago in reply to Former Member

    To simplify...

    Body mass is used to estimate basal metabolic rate (BMR) the amount of energy burnt by a body at rest.

    When you carry more weight during an activity your work rate usually increases as a function of the increased weight. This is reflected in the heart rate measured during that activity. Your heart rate during activity is used to estimate energy burn during that activity. 

    Therefore changing the amount of extra weight you carry during an activity will be reflected in the change in heart rate due to the change in effort. There is no need to make changes to the body mass entered on the device.

    Total energy burn for an activity is the sum of the BMR and energy burnt during an activity,

  • 0 over 4 years ago in reply to Former Member
    I don't understand how calories could be calculated on the basis of heart rate alone. Weight always factors in every calorie burn estimation I've ever seen.

    support.garmin.com/.../ 

    www.dcrainmaker.com/.../how-calorie-measurement-works-on-garmin.html

  • 0 over 4 years ago in reply to Dr Phil
    Dr Phil said:
    Total energy burn for an activity is the sum of the BMR and energy burnt during an activity,

    Yes. From manual : 

    „Calories burned is dependent on heart rate data, an accurate user profile, and the type of activity being recorded. In addition, the devices calculate both active and inactive (basal metabolic rate) calories to show the total calories burned on a daily basis.“

  • 0 over 4 years ago

    Have fun with the read below and white paper. I'm not sure if our question is answered or not. I still think your statement is valid. But as the same time, elevated hr from additional weight may cover it. But then again,  have a few shots and chain smoke, and your walk hr will show you're jogging. Or take alcohol tylenol and advil and have hr of 130 as you're laying down. 

    www.firstbeat.com/.../

  • 0 over 4 years ago in reply to AndreiDracul
    AndreiDracul said:
    have a few shots and chain smoke, and your walk hr will show you're jogging. Or take alcohol tylenol and advil

    I think in this case the backpack weight would be your smallest problem Slight smile

  • Former Member
    0 Former Member over 4 years ago in reply to Dr Phil

    Okay, so what is the evidence that the change in heart rate accounts for it? I see the assertion, but how do you know? Every link referenced so far (dcrainmaker, garmin support, firstbeat) all talk about weight (body) being one of the necessary inputs. So if heart rate alone is not sufficient for the calculation, then why would it be sufficient for the differential calculation when you're carrying extra weight? And if Garmin's algorithm does that, then it's quite likely it's inaccurate.

    I keep seeing assertions that heart rate takes the extra weight into account. I'm genuinely trying to be open minded but so far no evidence has been presented that shows extra weight should not be taken into account for an accurate calorie count and that heart rate alone is sufficient.