Accuracy of calories burned while biking

[nscrbug]

Linda, I just caught this thread but wanted you to know that I have a Garmin 500 and I have been having the same issue. We time trial on Tuesday evenings and without the hrm the Garmin says I burn around 550 calories in a 10 mile hilly tt with an 18 mph average (which I think is close to accurate); with the hrm the Garmin says I burn 225--usually cuts it in half. DH has a Garmin Edge 305 and his heart rate records in the 500-600 range for the same tt. I think it has something to do with the Garmin 500.

THIS!!! The first few times that I used the 500, I actually forgot to wear the HRM. Yet the calorie burn that was calculated for those rides, was nearly double what it is on rides when I DO wear the HRM.

Linda

[nscrbug]

I do not have a Garmin but have heard from others that the Garmin 500 does seem to be prone to reporting lower heart rates and under-estimating calorie useage.

Based on what Bike_Chick posted above, I'm starting to believe this myself.

[nscrbug]

To original poster: Why do you want this information? Training purposes? To gauge how much to eat? Just for kicks? Numbers nerd? I'm curious.

I'd have to say, "all of the above" as my answer. But mainly to gauge how many calories I need to consume in a day and how much activity I need to do. Ideally, I would like to lose a few pounds, but knowing these numbers will help to ensure that I won't GAIN any.

Linda

[nscrbug]

Linda,

It appears that your zones are off on the Garmin and is as you are always riding zone 1. As OakLeaf sudjested measure your pulse at the top of that hill and compare the 2 if they agree set your zones and MHR to that number.

Yes, it does appear that I never seem to get out of Zone 1, but for a few exceptions.

I am a little confused regarding your suggestions. So are you saying that I should lower my MHR to what it is after I climb a steep hill...instead of setting it at 176 (220 - 44)? If I got that right, then my MHR would end up being like 135...which seems awfully low. Can you explain a bit more?

Linda

[bellissima]

Yes, it does appear that I never seem to get out of Zone 1, but for a few exceptions.

I am a little confused regarding your suggestions. So are you saying that I should lower my MHR to what it is after I climb a steep hill...instead of setting it at 176 (220 - 44)? If I got that right, then my MHR would end up being like 135...which seems awfully low. Can you explain a bit more?

Linda

Linda, the 220-age doesn't work with everybody and it is meat to be a starting point. As an example I am 35 and my actual MHR is 195 and I've seen higher. if I use the formula 22-35 my MHR would be 185 and that is over 10 counts off on the other hand my friend is 42, his MHR from recorded races is 193, if we use 220-42= 178 also that is 15 counts off. At this point I would suggest to set your MHR at 135 and see if you get more realistic numbers. Also do another effort on that hill and try to measure your pulse to see if it is in line with your Garmin reading.

[Bike Chick]

Linda, based on both our experiences with this, I'm going to do some research on the Garmin site and let you know what I find out.

We did the 15 mile TT course last night with some grueling hills. My time was 50 minutes with a 17.1 average. I did not wear my hrm and the Garmin said I burned 759 calories. Just for comparison I went to caloriesperhour.com and put the info in and it said I should've burned 690 which is pretty close. Had I worn the hrm, it probably would've said 350!

[Bike Chick]

I just googled the term "Garmin 500 not calculating calories" and got a page full of the same complaints. Many forums, including Garmin's, have posts that address this issue so it's not just us. What I did read is that Garmin is aware of the issue and they will be coming out with a firmware upgrade to fix it soon. All I can say is just keep upgrading your Garmin when there is a firmware upgrade and see if it fixes the problem. Everything else on the 500 works great and I'm pleased with the computer in every other aspect.

[tongue_tied]

I mostly don't use the HR strap with my 500 because it gets irritating sometimes. But I've noticed that the 500 overestimates the calories burned, IMO, on a ride without the use of the strap. I was on the North Branch Trail this past Saturday, finished a 60 mile ride, and burned something like 3300 calories in 3 hours. No real climbing. My avg speed was 18mph. Even at 175, I think that's overestimating.

I've just learned that it's a loose gauge of calories burned.

[hulagirl]

coming into this late but my hubby has an extremely low HR.

He's in the 40's sometimes.

Has had ER people totally FREAK OUT on him.

But, he's a marathon runner and in very fine shape.

My HR just getting out of the house is your average HR on the bike! My Max is 180ish. My resting is in the 60-70 range.

When I run with my husband, I get into the 150's while he's MAYBE at 100.

But when we bike, I average lower than he does as I'm a more efficient biker. (on a lighter bike too)

If you know your resting HR, it will tell you a lot about your results. If you are not working hard enough to get that HR up, you won't burn the calories. You are efficient. Your heart is strong. (as long as you have a good recovery HR too!) And the better you are at something, the less you will have to work at it.

You do sound like my husband, very low HR. And that's just what you have to work with. Make sure you enter your resting HR in the garmin as well. That will help change the calculations.