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Does a low resting heart rate affect your calorie target zone during exercise?

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I bought a HRM and based on age and sex, it says my calorie burning "target zone" is between 130 and 170.  I was just wondering if that could be different based on my usual heart rate which has always been rather low even though I'm not an athlete ... it hovers between 45-55 on a regular basis and, when actually resting is closer to 45.  Anyway, I find I'm breaking a sweat and getting that "pumped" feeling when my HRM reads at about 110/120.  I've gotten my heart rate up over 160 a few times and feel like I'm going to pass out.  Is this normal?  Am I pushing too hard because of the huge difference between my regular heart rate and my arbitrarily assigned "target zone"? 

Also, if I change my "target zone" on my HRM, will it affect the number of calories registered as burned to reflect the same amount of exertion I would be having at that higher number?

As you can see, I'm a bit confused.  I've looked up a few topics on low heart rates here and, like my doc, they said in itself it isn't a bad thing.  I didn't find one that addressed this specifically, though.  Thanks in advance.

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Target training zones are based on a percentage of maximum heart rate, not resting rate.  If your HRM ask for your age and not your max heart rate chances are your training zones are off. 

See link for info on max heart rate: eart-rate.htm

And, yes if your zones are set incorrectly it will effect what the HRM is showing as estimated calories burned.

When I entered my age, sex, wgt, height into tmy HRM, it automatically gave me my training zone.  It did not need my max heart rate cause it figured it out by itself using the 220-age x 70-90% rule for finding my zone.  It calculates my calorie burn not on where I am in my zone, but on my actual heart rate.  The zone s only there to give a workout range for your heart rate, it's more of a formality than a calculator for calories burned.

I also have a low resting heart rate and it takes alot of work for me to get my HR up.

Based on what you have said, you would probably be better off if you use your HRM in conjunction with the Scale of Perceived Exertion (Borg Scale).  The Borg scale is a method of determining how hard you are working by the way that you feel.  To simplify it, say the scale goes from 1-10 (it really goes from 13-20, but I digress).  At a 1, you are at complete rest -- at a 10 you are at your maximum heart rate (what you describe as "I feel like I'm going to pass out").  To work in your target zone (usually 60 - 80% of your Maximum Heart Rate), you should be working hard enough so that you can't sing, but you can talk at the lower end of the scale in complete sentences, and in shorter phrases at the high end of the scale.  To work above your target zone (usually 85% MHR), you would want to work hard enough so you can only get out a few words.  Using this scale, along with your HRM, should give you a better idea of your actual MHR and target zone percentage numbers.  Good luck!

If your HRM only allows you to enter age and not max heart rate then you may need to lie about your age so the target zones are correct.  220 - age doesn't not in most cases result in a correct max heart rate.  For reference see the link above. 

Thank you all so much for taking the time to reply and being helpful.  :)

trhawley, that was a really informative article and I'm going to try some of those tests as soon as I get a chance.  I want to try to be accurate and all and, if in the end I must lie to my HRM, I think I can live with that.  ;)  I also had no idea that your MHR varied with the kind of activity you were involved in which, now that I think about it, makes much more sense, so thanks again. 


jem599, may I ask what kind of HRM you use, please?   And I'm so glad I'm not the only one that feels they are working very hard to get their HR up.  I was getting a bit self-conscious about being what I thought was so out of shape.  I mean, I know I need improvement but I didn't think I was doing that bad, lol.  Glad to know it can be due in part to my naturally low heart rate and that I'm not alone.  ;D  Thank you much.


I'd never heard of the Borg scale before, paularuck.  I'm going to look that up, too.  It sounds very helpful to me and I hope to be able to make good use of it.  I know when I push myself hard (without feeling that overworked feeling) that I can't sing and yet feel like I have more energy for that time.  If I can still talk reasonably well, I somehow end up feeling less energy and less focused.  I think I'll be able to use these guidelines to keep myself in check so thanks a lot.


Just want to say I'm grateful for all the support I've seen here, not only for myself as a newbie but just in general, and that I'm so glad I found this website, too.  <3

I did check the above link and using that formula gives me just about the same max heartrate as the 220-age formula...only 4 beats more per minute.

I use the Polar F4 HRM...

To clarify, my resting heart rate is low because I've benefitted from alot of HIIT...I was out of commission due to a back injury for a couple of years and just got back into working out in Jan..

At that point my resting hr was 91...I've now gotten it down to 59...I've also lost 46 lbs...It's the combination of those things that makes it very difficult to get my hr up, but several good heavy sets of deadlifts can get it up...

If you have serious concerns, you should probably consult your doctor.  There could be a medical reason behind your problem.

Good Luck

There are other ways to figure your hr zones besides the standard 220- age formula many of which that take into the calc your resting heart rate. eart-rate.htm ;

that site has some detailed tests to determine your Mhr  

My polar F11 HRM has a vo2 max test My resting hr is 48  It takes a lot for me to get it up to 105 my bare minimum.  My Max based on standard formula is 156 but I've done 160 with little problem - but I will be very tired and breathing hard.  My HRM aslo has the ownzone where for the first 5 minutes it measures my hr and then determines what my work out zone needs to be that day.  Sometimes its more than the standard sometimes its the same.

There are other formulas where you take the standard 220 age and use the resting heart rate but I can't find my bookmark to that formula but search this forum and you'll find it. 

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