Skip navigation
Community: Exchange advice in the forums and read running commentary Resources: Personal running log, calculators, links and other tools for runners News: Running news from around the world Training: Articles and advice about fitness, race training and injury prevention Races/Results: Find upcoming races and past results Home: The Cool Running homepage
Cool Running homepage  Search Cool Running Community

2296 Views 7 Replies Latest reply: May 30, 2011 4:56 AM by how2runfast RSS
Himelda Rookie 4 posts since
Apr 19, 2011
Currently Being Moderated

Apr 19, 2011 5:44 AM

Heart rate and calories from fat

I know that to burn more fat you have to train inside some "heart rate zone".
I've found a few tables around, based on sex, age, etc, but it seems weird that they don't usually account, for instance, for my BMI or my training status etc.
Is there some well-respected source that I can read to get a better understanding of all this, without going to med school :-)?
Is there some "serious" website/app that will take like bunch of my biometrics and give me back a "reliable" figure of my heart rate zone? (quotes to say that I don't need 100% certainty, but I'm not really satisfied with oversimplified tables with no backing theory).
Thank you guys!

 

-Himelda

  • lenzlaw Community Moderator 10,369 posts since
    Jan 18, 2008
    Currently Being Moderated
    1. Apr 19, 2011 7:21 AM (in response to Himelda)
    Re: Heart rate and calories from fat

    Generally speaking, by running slower you burn a higher percentage of calories from fat.  The trade-off is you don't cover as many miles in an hour, so you burn fewer calories overall in a given time.  Speed and body weight also have some effect on the number of calories burned (see the article at the first link below).   BMI and fitness level don't have any effect on heart rate zones, according to the experts.  Though as you gain fitness you should find it easier to run in a particular zone, and you'll probably be faster in that zone.  The second article below is a good guide to using a heart rate monitor and determining your training zones.  It has a calculator for zones based on what you determine is your resting heart rate and your maximum heart rate.  Maximum is the hard part.  There are several formulas but none are accurate for everyone and some only work for about 50% of the population.  Have fun!

     

    Len

     

     

    (How many calories are you really burning?)

    http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

    (Heart Monitor Training)

    http://www.marathonguide.com/training/articles/HeartMonitorTraining.cfm





    Len

  • LauraSmith77 Rookie 1 posts since
    Apr 19, 2011
    Currently Being Moderated
    3. Apr 19, 2011 11:37 AM (in response to Himelda)
    Re: Heart rate and calories from fat
    Hi Himelda,
    I'm a biologist so I thought I'll chime in :-).
    There is a lot of literature on fat oxidation (which is the technical term for "burning fat") and its relationship with exercise AND training status. Unfortunately, most of it is not freely available on the web, and I assume you don't have access to PubMed.
    The results are relatively simple to sum up:
    - there is a non-linear relationship between fat oxidation and %VO2max.
    - for maximum accuracy, the relationship should be calibrated on each athlete
    - however, you can get a reasonable estimate without calibration, once you account for sex too.
    Note that the relationship is with %VO2Max, not with %HRMax. So your heart rate alone won't cut it. Your VO2 and VO2Max are the secrect ingredients :-) that account for your fitness status. The second link you got from Len is indeed using your HRMax/RHR to sort of "estimate" your VO2Max, but as you understood, is not a model of fat oxidation.
    If you want to learn more, and don't mind a slightly "technical" approach, the best reference I've found that you can download for free is:
    Optimizing Fat Oxidation Through Exercise and Diet, Juul Achten, PhD, and Asker E. Jeukendrup, PhD, School of Sport and Exercise Sciences, University of Birmingham
    here:
    (doesn't look like an official link so I don't know how long it's gonna be available there)
    About the second part of your question (websites). Most papers don't give the actual equation, so it's not trivial to build a working model.
    That said, I'm a runner, I use a Garmin Forerunner, and in the last few months I've been using a free app (SportieTech Studio, http://www.sportietech.com/studio) to analyze my workouts.
    A little buried under My Profile - Body/Fitness Charts there is indeed a chart representing %calories from fat Vs heart rate. As I understand it, they use a model very similar to the one in the paper above, and in facts, when you create your user profile you are either asked to enter your VO2Max (if you know it) or guided through a few ways to estimate it (a Cooper test, or that HRMax/RHR thing again). They also ask for your weight etc.
    As I said, the chart you get looks very similar to the paper above. When I got mine, I did a few calculations and it seems to be pretty accurate in my case (can't vouch for others, but working in a lab I know myself pretty well :-)
    That chart is useful to set your heart rate zones during training. If you run with a Garmin, as I do, you can also upload the data to the studio, and you'll have a chart of your calories over time/distance (which I get are estimated again from VO2/VO2max, unlike what my garmin does) AND a chart of calories from fat (again over time/distance), which are always nice to see :-).
    Hope that helps!
    Laura
  • how2runfast Legend 207 posts since
    Sep 21, 2008
    Currently Being Moderated
    5. Apr 30, 2011 11:11 AM (in response to Himelda)
    Re: Heart rate and calories from fat

    Why are you trying to burn more fat?  Are you trying to improve your body's ability to use fat as fuel in long races like marathons or ultramarathons?  Or are you just trying to lose weight?

     

    If you are trying to lose weight, it's doesn't really matter whether you are burning fat or gylcogen.  In fact, the faster you run, the more calories you will burn, but the higher the percentage of them will be from glycogen vs. fat.

     

    Weight loss results from burning more calories than you consume.  Your body doesn't care whether you burn calories from fat or glycogen during your workout or not.

     

    Recent studies have shown that if you run fast enough, you continue to burn calories at an elevated rate, long after your workout is over.

     

    Here's a blog post that I wrote about it:

     

    How to Keep Burning Calories Long After Your Workout is Over





    Mike

    Boston Marathon Finisher

    How 2 Run Fast

    Follow me on Twitter

    Albany (NY) Times Union Runners Blog

  • how2runfast Legend 207 posts since
    Sep 21, 2008
    Currently Being Moderated
    7. May 30, 2011 4:56 AM (in response to Himelda)
    Re: Heart rate and calories from fat

    To lose bodyfat, you have to create a calorie deficit.  You have to  burn more calories than you are taking in.  If you run slowly, you will  burn a higher percentage of fat vs. carboydrates, but you will burn a  much smaller total amount of calories.  If you run faster, you will burn  more calories and your body will have to burn fat to replace your  glycogen stores.

     

    If you run at a slow pace that  maximizes fat burning, it  will take you much longer to lose your  bodyfat, because the rate at  which you are burning calories is much  lower.

     

    What’s Your Fat Burning Zone?  Who Cares?

     

    Here are some links the other studies that I referenced.

     

    Working out at 50% of VO2max produces no calorie afterburn.

     

    http://www.ajcn.org/content/69/5/927.full.pdf

     

    Increasing fat burning has no effect on bodyfat

     

    http://www.cell.com/cell-metabolism/abstract/S1550-4131%2809%2900372-6

     

    Fat oxidation doesn't results in weight loss, calorie deficit does

     

    http://www.nutrifit.co.uk/Conference_bham_2008/articles/Jeukendrup_fat%20burning.pdf





    Mike

    Boston Marathon Finisher

    How 2 Run Fast

    Follow me on Twitter

    Albany (NY) Times Union Runners Blog

More Like This

  • Retrieving data ...

Legend

  • Correct Answers - 10 points
  • Helpful Answers - 7 points