Heart Rate in association with Calories Burned question!

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PRORACER18
PRORACER18 Posts: 5 Member
in Fitness and Exercise
My husband and I have recently started using the UA band, scale and chest monitor in addition to tracking our food, exercise, macros, etc.....

We have both been doing Crossfit for about 4 years, and I have worked out most of my life before this....I have a resting heart rate of 42 (unless I'm asleep, and it goes into the 30's), while he has a resting heart rate more like in the mid 60's.
When we both do the same workouts at the same intensity, he burns three times as many calories as I do, according to Record and our heart rate monitors.

I am synced all the time, in an effort to be very accurate on my food intake and caloric expenditure, as I am trying to lose some fat without losing muscle, so here is my big question:

Am I truly burning so many fewer calories, or is this a result of the tracker's inability to account for my resting heart rate and my heart rate when I am pretty much maxed out? Maxed out for me is around 165bpm....and I mean that is working very hard, lungs are maxed out, etc. My husband is right around 200bpm when he is at max effort.
Mostly, I just want to make sure my caloric intake each day is pretty spot on, and if I'm showing fewer calories burned than what I'm actually burning in a workout, I will need to figure out how to adjust that (hopefully there is a formula somewhere).

Thank you in advance! :)

Replies

  • sijomial
    sijomial Posts: 19,811 Member
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    You have highlighted two problems with the very loose association between HR and calories - in reality HR is being used as a proxy for oxygen uptake but that's hardly convenient to measure.

    Crossfit is an awful exercise to use HR to try and get a calorie estimate as your HR is rising for factors other than oxygen need - the number you are getting is meaningless and probably dreadfully exaggerated.

    Second problem is individual variation in HR, I've seen people burning almost exactly the same calories doing steady state cardio (when heart rate is more useful) with HR's 40% different.
    As an outlier you are a long way from average.
  • PRORACER18
    PRORACER18 Posts: 5 Member
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    Yes, he weighs 220 (BF is 19%) while I weight 147 (BF is also 19%), so I do expect him to burn more, but just not that much more....I was just hoping there was some sort of "resting heart rate:max effort heart rate" ratio for caloric expenditure that I could use to get me a little closer. I feel for the effort I'm putting out that I should be burning more than I'm being shown.

    Is my only solution to tweak everything (macros, calories, etc) every couple of weeks then, despite what I'm logging through my band?



  • jjpptt2
    jjpptt2 Posts: 5,650 Member
    edited December 2017
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    There are sooo many variables at play here that it's hard to say for sure. But thinking about it logically, calories burned is a reasonable measure of work done. HR has no bearing on work, but bodyweight certainly does. If you weight 2/3 that of your husband, it's reasonable to think you'd burn proportionally fewer calories, assuming you do similar workouts at similar intensities. Now, if your husband is using more resistance (weight or whatever) than you are, that could also skew the numbers in his favor.

    Saying he burns 3x as many seems high, but as previously said, estimating calorie burns for crossfit (and similar) workouts is near impossible.

    Your best bet, probably, is to stop comparing HRs and calorie burns, and focus more on your own numbers and your own progress. Estimate your expected weight loss based on the numbers/math, then compare that to your actual. If they are fairly close, then your estimates are probably pretty good. If not, tweak something and repeat the process.
  • sijomial
    sijomial Posts: 19,811 Member
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    PRORACER18 wrote: »
    Yes, he weighs 220 (BF is 19%) while I weight 147 (BF is also 19%), so I do expect him to burn more, but just not that much more....I was just hoping there was some sort of "resting heart rate:max effort heart rate" ratio for caloric expenditure that I could use to get me a little closer. I feel for the effort I'm putting out that I should be burning more than I'm being shown.

    Is my only solution to tweak everything (macros, calories, etc) every couple of weeks then, despite what I'm logging through my band?

    There's no resting HR = calories formula.
    As an example my resting HR dropped 20% from 60 to 48 because I got much fitter and as part of that my heart is pumping better. Because I'm much fitter my calorie burns are far higher (25%) despite my HR being lower.

    Some more sophisticated HRMs allow you to program in min and max HR (that needs to be a tested max HR though) to personalise the estimates. But that's zero help with Crossfit.

    Just log the type of workout using the appropriate estimate from the database depending on your workout of the day - it will give you a better estimate.

    Yes your feedback loop is very sensible, both for food logging inaccuracy (far more significant) and exercise inaccuracy. Not every couple of weeks though - think much longer term.

  • cwolfman13
    cwolfman13 Posts: 41,874 Member
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    PRORACER18 wrote: »
    Yes, he weighs 220 (BF is 19%) while I weight 147 (BF is also 19%), so I do expect him to burn more, but just not that much more....I was just hoping there was some sort of "resting heart rate:max effort heart rate" ratio for caloric expenditure that I could use to get me a little closer. I feel for the effort I'm putting out that I should be burning more than I'm being shown.

    Is my only solution to tweak everything (macros, calories, etc) every couple of weeks then, despite what I'm logging through my band?



    Outside of some very expensive equipment or a power meter on a bike, everything is going to be an estimate. HRMs can provide a reasonable estimate for a steady state cardio event given that your HR is used as a proxy for oxygen uptake...steady state cardio is a good way to measure VO2 max and thus there is some correlation.

    CF and stuff like that...HIIT...weight lifting, etc isn't a good way to measure VO2 max and thus their is little correlation between your HR and energy expenditure...spikes in your HR simply inflate your energy expenditure in this case.
  • PRORACER18
    PRORACER18 Posts: 5 Member
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    Thank you everyone! All good info!

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