Heart Rate Monitor Training - Are you burning fat or carbs?

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Here is something that may be of interest to those who train with a heart rate monitor (HRM).

Hopefully you are using an fitness app along with your HRM that provides a precise macros-burn calculation (I use Digifit), as you can get a better idea of what you are burning in terms of fat and carbs, not just a total calorie burn. In general, exercise in lower HR zones tends to burn more fat, while exercise in higher HR zones burns more carbs. (This isn’t exactly a revelation to those that have studied up on HRM training, but it may be helpful in terms of putting it into the context of calorie counting on MFP)

For example, here is the data from a few of my workouts (HRM measured):

1) Strength training – 47 minutes (84% spent in HR Zone 1)
-calories burned: 282
-fat calories: 157 / Fat % 56
-carb calories: 125 / carb%: 44
- (note, don’t get hung up on whether an HRM is completely accurate for non-steady state exercises. My calorie burn for strength training is within the realm of reasonability for most calorie burn charts I have referenced (usually lower). In reality, you lift, your HR increases, you rest, it decreases, etc…)

2) 10 Mile Run – 85 minutes (86% spent in HR Zone 4 or greater)
-calories burned: 1,277
-fat calories: 89 / Fat % 7
- carb calories: 1,188 / carb%: 93

This should be persuasive to those who are attempting to burn fat! I’m in maintenance mode and divide my time equally between strength training and running, but those who want to lose weight may want to consider leaning toward exercises with low to mid-range HR zones to burn more fat.

This should also influence the way that you eat the rest of the day, which may not be according to the calculations that MFP provides. When MFP increases the daily calorie allowance based upon exercise calories burned, it increases it in proportion to your predetermined goals (carbs-45%, fat-25%, protein-30%, for example). So for the run example above, instead of recommending that I almost exclusively carb up, MFP just allocates 45% more calories to carbs, and also bumped my protein up to a ridiculous sum of 285 grams! (I requested the capability to enter specific macros burned as an enhancement to MFP, so perhaps that will be available in the future.)

MFP Daily allocation (no exercise):
F-70
C-284
P-189

MFP recommended allowance for 1,277 calories burned:
F-105
C-428
P-285

HRM recommended allowance for 1,277 calories burned:
F-80
C-581
P-189 (MFP recommendation carryover)


This definitely impacts your diet for the remainder of the day! I can do this type of calculation on the side every time I exercise – it’s not that I plan on eating back a lot of the fat grams I lose, but it is good to know the effect that your exercise is actually having on your macros allocations when making nutrition choices.

Replies

  • 111YoYo111
    111YoYo111 Posts: 213 Member
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    I bought a Garmin HRM without realizing that I can't get the Garmin Connect program on my IPad or IPhone. Do you know how to calculate your zones? It should depend on your resting heart rate should it not? I had a MIO last and it asked for that info but this one doesn't.

    thanks
  • Bry_Fitness70
    Bry_Fitness70 Posts: 2,480 Member
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    111YoYo111 wrote: »
    I bought a Garmin HRM without realizing that I can't get the Garmin Connect program on my IPad or IPhone. Do you know how to calculate your zones? It should depend on your resting heart rate should it not? I had a MIO last and it asked for that info but this one doesn't.

    thanks

    I have a MIO Alpha HRM that Bluetooths to the DigiFit app. Within DigiFit, there is a CP30 assessment (along with several others), which has you do cardio as rigorously as possible (I ran on a treadmill) for 30 minutes, then stand still for 2 minutes immediately after so that your recovery rate is calculated. From that, your V02, LTHR, and HR Zones are calculated.

    I'm surpised that Garmin doesn't have something for iPhones/iPads! Your Garmin HRM may be readable by DigiFit
  • r_kraft
    r_kraft Posts: 27 Member
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    The Garmin Connect app is for the phone via blue tooth, I use the web site on my IPad. I have used the app on both an Iphone 4s and the new Iphone 6 with no issues. I have a HRM and a Garmin FR220 GPS watch. It is the Watch that interfaces with both the HRM and the phone. I use the app when I am on my run and after I do the edits (name the work and notes) on the IPad.
  • 111YoYo111
    111YoYo111 Posts: 213 Member
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    r_kraft wrote: »
    The Garmin Connect app is for the phone via blue tooth, I use the web site on my IPad. I have used the app on both an Iphone 4s and the new Iphone 6 with no issues. I have a HRM and a Garmin FR220 GPS watch. It is the Watch that interfaces with both the HRM and the phone. I use the app when I am on my run and after I do the edits (name the work and notes) on the IPad.

    When I tried to download the app on both devices I got an error message that it is not supported on this device??? Am I doing something wrong?
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    None of this makes sense to me... but maybe it's because I'm in a bit of a fog from being sick.

    Burning carbs vs burning fat? Shouldn't it be burning sugars vs burning tissue, and if burning tissue, then burning muscle vs burning fat?

    Also, how do you say all that without the context of diet? If I run fasted, I'm pretty sure I'm burning more tissue than I am stored sugars, regardless of the effort/HR zone as compared to running "on a full stomach", for lack of a better phrase.

    Last, I would think the source of the energy for your workout can change as the workout goes longer. For example, I'd bet I'm burning mostly stored sugars for the first 30 minutes, but I bet I'm burning very few sugars at hours 5 and 6 (depending on how much I'm consuming during the workout).

  • Bry_Fitness70
    Bry_Fitness70 Posts: 2,480 Member
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    jacksonpt wrote: »
    None of this makes sense to me... but maybe it's because I'm in a bit of a fog from being sick.

    Burning carbs vs burning fat? Shouldn't it be burning sugars vs burning tissue, and if burning tissue, then burning muscle vs burning fat?

    Also, how do you say all that without the context of diet? If I run fasted, I'm pretty sure I'm burning more tissue than I am stored sugars, regardless of the effort/HR zone as compared to running "on a full stomach", for lack of a better phrase.

    Last, I would think the source of the energy for your workout can change as the workout goes longer. For example, I'd bet I'm burning mostly stored sugars for the first 30 minutes, but I bet I'm burning very few sugars at hours 5 and 6 (depending on how much I'm consuming during the workout).

    Since we don’t eat pure sugar (well, most don’t) and human tissue, it seem preferable to discuss it in terms of carbs and fat, I’m sure that is why the app expresses it in those terms;)

    The calculated carbs and fat burned are based upon the limited data entered into the app, including weight, age, sex, and HR. If you know of an app that can then add in additional data like “having a full stomach”, fasting, stored sugars, etc., that would certainly increase the accuracy. I’m not sure how you would do that short of blood samples, and most have no interest in doing that every time they exercise.

    Most of us are not in the world of competitive exercising, so the basic resources available in free fitness apps will have to do for now – this is the audience for this post.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    edited November 2014
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    bw_conway wrote: »
    jacksonpt wrote: »
    None of this makes sense to me... but maybe it's because I'm in a bit of a fog from being sick.

    Burning carbs vs burning fat? Shouldn't it be burning sugars vs burning tissue, and if burning tissue, then burning muscle vs burning fat?

    Also, how do you say all that without the context of diet? If I run fasted, I'm pretty sure I'm burning more tissue than I am stored sugars, regardless of the effort/HR zone as compared to running "on a full stomach", for lack of a better phrase.

    Last, I would think the source of the energy for your workout can change as the workout goes longer. For example, I'd bet I'm burning mostly stored sugars for the first 30 minutes, but I bet I'm burning very few sugars at hours 5 and 6 (depending on how much I'm consuming during the workout).

    Since we don’t eat pure sugar (well, most don’t) and human tissue, it seem preferable to discuss it in terms of carbs and fat, I’m sure that is why the app expresses it in those terms;)

    The calculated carbs and fat burned are based upon the limited data entered into the app, including weight, age, sex, and HR. If you know of an app that can then add in additional data like “having a full stomach”, fasting, stored sugars, etc., that would certainly increase the accuracy. I’m not sure how you would do that short of blood samples, and most have no interest in doing that every time they exercise.

    Most of us are not in the world of competitive exercising, so the basic resources available in free fitness apps will have to do for now – this is the audience for this post.

    Agreed. As such, shouldn't most people simply focus on burning as many calories as they can, especially given the inaccurate nature of all this? And I have no idea what that first sentence means.


    I'd be very curious to see the numbers the app gives back for a 1 hour run mostly in zone 4 or higher vs a 1 hour run in mostly zone 2/3.

    And just to be clear... it's not that I disagree with the general point of this, I just think it's hugely overstated and generally not beneficial to the average MFPer.
  • r_kraft
    r_kraft Posts: 27 Member
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    Not sure why you would get the error, what IOS version are you running on your phone?
  • Bry_Fitness70
    Bry_Fitness70 Posts: 2,480 Member
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    Agreed. As such, shouldn't most people simply focus on burning as many calories as they can, especially given the inaccurate nature of all this? And I have no idea what that first sentence means.

    I'd be very curious to see the numbers the app gives back for a 1 hour run mostly in zone 4 or higher vs a 1 hour run in mostly zone 2/3.

    And just to be clear... it's not that I disagree with the general point of this, I just think it's hugely overstated and generally not beneficial to the average MFPer.

    More precise data (not perfect) is better than guesswork. The available resources for this were a HRM and a smartphone. So consider it with those constraints –a full metabolic assessment is beyond the scope of most MFP users.

    In the example above, MFP calculated that I should eat 285 grams of protein following a 10 mile run. That is far too much for a person who is 6ft 165lbs to eat. It is just a blind calculation based upon total calories burned and my preset macros ratio. Tweaking your MFP macros reallocation according to estimated fat / carb burning calculations is a step toward more precision.

    Is it a perfect methodology? Not at all. Is it better than taking a predetermined % and eating back calories without regard to HR Zone data? I believe so.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    bw_conway wrote: »

    Agreed. As such, shouldn't most people simply focus on burning as many calories as they can, especially given the inaccurate nature of all this? And I have no idea what that first sentence means.

    I'd be very curious to see the numbers the app gives back for a 1 hour run mostly in zone 4 or higher vs a 1 hour run in mostly zone 2/3.

    And just to be clear... it's not that I disagree with the general point of this, I just think it's hugely overstated and generally not beneficial to the average MFPer.

    More precise data (not perfect) is better than guesswork. The available resources for this were a HRM and a smartphone. So consider it with those constraints –a full metabolic assessment is beyond the scope of most MFP users.

    In the example above, MFP calculated that I should eat 285 grams of protein following a 10 mile run. That is far too much for a person who is 6ft 165lbs to eat. It is just a blind calculation based upon total calories burned and my preset macros ratio. Tweaking your MFP macros reallocation according to estimated fat / carb burning calculations is a step toward more precision.

    Is it a perfect methodology? Not at all. Is it better than taking a predetermined % and eating back calories without regard to HR Zone data? I believe so.

    Eating back calories has nothing to do with HR zones, it has to do with calories burned. How those calories are broken down (f/c/p)... yes, I agree that MFP's equal allotment probably isn't best. But that wasn't the larger point I took away from your post.
  • erickirb
    erickirb Posts: 12,293 Member
    edited November 2014
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    You lost me with #1. as in it is wrong.

    Using the HRM for strength training is just guess work, your HR is elevated for different physiological reasons, and therefore the cals burned during the workout have very little if anything to do with actual HR.

    HRMs use HR as a proxy for how hard you are working to get an idea of the oxygen uptake, which is what burns cals. Your HR though elevated for strength training does not have the same effect on oxygen uptake. That said, zones are a crock of *kitten*, you may burn more fat vs carbs, whatever, but if your Net caloric intake for the day is the same it will have very little impact on body composition at all. It may matter slightly for highly trained athletes but not for the general population. Follow a program, work hard, keep diet in check get results.
  • AgentOrangeJuice
    AgentOrangeJuice Posts: 1,069 Member
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    I learned to keep my heart rate in the optimal fat burning zone while doing DDP Yoga. 180 minus my age 36 = 144 and 20 bpm below that. So my optimal fat burning zone is 124-144 and I work to keep my heart rate in that target area.
  • nicolen160
    nicolen160 Posts: 197 Member
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    I looked in the google play store for Digifit and all it came up with was iCardio, is this the same app? very interested in this
  • 999tigger
    999tigger Posts: 5,235 Member
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    I thought the fat zone thing had all been discredited as a marketing ploy.
    Whilst time in the lower fatburning zone will burn more fat as a %, time spent in the higher anerobic zone will burn less fat as a % but more fat overall.

    I also wouldnt use a HRM for strength training.
  • h7463
    h7463 Posts: 626 Member
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    Hi! I use a Polar H7 with the Polar Beat app on an iPhone 4s, and this is my personal experience:

    My training revolves mostly around weights, and the cardio days are very limited. During my app. 1 hour lifting sessions, I maintain an average HR of 120-140 for the duration, while pushing HR zones 3-4 (of 5). This is possible for me, because I keep the chit-chat to zero, watch my rest times between sets, and sometimes pass the time with dynamic stretching or light cardio moves to keep my HR up.
    Having my macros micro-managed like you listed above, makes not much sense for my training, because on some days, I just have to 'feel out' how much carbs I need, in order to provide the energy that I need. That's a very personal thing, that neither the HR monitor nor MFP can do for us. I look at the c/f/p numbers as guidelines, rather than set in stone. There has been a lot of trial and error for me to get to this point, and I wouldn't trust a computer with any of it.....lol
    MFP clearly has it's limits, as far as the calculations go, and it simply resorts to filling the pre-set percentages for the macros, because it expects the calories to be 'eaten back', regardless of the type of exercise they come from. It's just a simple free gadget. I keep a log with personal notes, so I know what's been going on, and can monitor my progress.
  • The_Enginerd
    The_Enginerd Posts: 3,982 Member
    edited November 2014
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    The "fat burning zone" was pretty debunked long ago I thought. Total fat loss over a long period of time is going to be determined by your calorie deficit alone (along with some dependence on adequate protein levels and training).
    bw_conway wrote: »
    This should be persuasive to those who are attempting to burn fat! I’m in maintenance mode and divide my time equally between strength training and running, but those who want to lose weight may want to consider leaning toward exercises with low to mid-range HR zones to burn more fat.
    This, specifically, is not necessary. How much fat versus glycogen you are burning during your workout is not going to matter in the big picture. This is really losing the forest from the trees by concentrating on that. Yes, the fat/glycogen burned ratio is higher while you are working out, but total fat burned is lower, and where that energy comes from in the short term is not going to matter in the long run. To reiterate: total fat loss over a long period of time is going to be determined by your calorie deficit.

    edit: This link does a pretty good job of getting to the crux of the matter: http://www.builtlean.com/2013/04/01/fat-burning-zone-myth/
  • AgentOrangeJuice
    AgentOrangeJuice Posts: 1,069 Member
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    I never looked into debunking the fat burning myth, I followed the program and lost 75 lbs and still going.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    I never looked into debunking the fat burning myth, I followed the program and lost 75 lbs and still going.

    The question isn't whether or not you can lose weight working out in certain zones. The question is whether or not there's a meaningful advantage to doing so.
  • Azdak
    Azdak Posts: 8,281 Member
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    erickirb wrote: »
    You lost me with #1. as in it is wrong.

    Using the HRM for strength training is just guess work, your HR is elevated for different physiological reasons, and therefore the cals burned during the workout have very little if anything to do with actual HR.

    HRMs use HR as a proxy for how hard you are working to get an idea of the oxygen uptake, which is what burns cals. Your HR though elevated for strength training does not have the same effect on oxygen uptake. That said, zones are a crock of *kitten*, you may burn more fat vs carbs, whatever, but if your Net caloric intake for the day is the same it will have very little impact on body composition at all. It may matter slightly for highly trained athletes but not for the general population. Follow a program, work hard, keep diet in check get results.

    Thanks for saving me some work.

    Just to add two things: not only is HR irrelevant for estimating weight lifting calories, but to try to then use that data to determine substrate breakdown is even more over the top.

    Zones have some value for training, but not for weight loss. And it has been shown that the fuel substrate burned during exercise has virtually zero effect on losing stored body. (Melanson et al: Exercise does not increase 24 hr fat oxidation).