Accuracy of calories burned while biking

[nscrbug]

So I've been using my Garmin Edge 500 for a few weeks now and really like it. I think it's really cool to upload my rides to Garmin Connect and see all the ride data and graphs. The one thing that has me a bit skeptical is the amount of calories burned. I'm just not sure that I trust it, and I'd like to get opinions from others that are using the 500 to see if their results are similar.

I wear the HR strap (and yes, I do have it on correctly, as I've read that this can make a difference), and I wet the sensor patches on it before putting it on. I've entered my profile information correctly - weight/height/gender, etc. So here are the stats from my last 2 rides -

Ride 1
Time - 04:33:17
Distance - 71.05mi
Elev Gain - 659ft
Ave Temp - 56.5F
Avg Speed - 15.6mph
Avg HR - 108bpm
Max HR - 132bpm
Calories - 771

Ride 2
Time - 04:41:32
Distance - 73.33mi
Elev Gain - 1,745ft
Avg Temp - 76.5F
Avg Speed - 15.6mph
Avg HR - 109bpm
Max HR - 144bpm
Calories - 862

FWIW...I'm roughly 157lbs + bike weight (5'6" & 45 yo). I don't know, but the calorie burn seems awfully low for 4+ hour rides. My average HR is low too, which seems odd especially since I feel like I'm working SO hard (it was windy on both of these rides). I can't seem to ever get my HR very high when riding, as is clearly displayed by my MAX HR on either ride. Yet the effort I put out feels like I'm not just pedaling at a leisurely pace, I'm fighting to keep up with my riding buddy who is quite a bit faster than me...so I don't get it. It's kind of discouraging in a way...to feel exhausted/sore after a long ride, knowing you worked hard...then to see the results of your efforts, only to discover that the numbers are disappointing. I can burn an equal amount of calories at the gym doing cardio and weights in half the time it took me to burn the same amount on a 4 1/2 hour ride. I'm confused by this.

Linda

[MaTadams]

The calorie burns seem low to me. I've used a Polar HRM in the past and its estimates were definitely higher than my Garmin, but your estimates seem unusually low. Have you tried any of the online calorie burn calculators to compare?

[amb]

I have a polar HRM that is not near as fancy. It's meant more for fitness classes and such, not biking. Here are my stats from today:

Distance: 24 miles
Total time: 1h:42m (incl stops)
Terrain: sort of flat, slight hills
Avg HR: 141
Avg speed: 15 mph +/-
Cal burned: 750

About me: 33yo, 5'-7", 130 lbs.

To me, your calories seem very low for 4+ hrs of riding but what do I know?! I often wonder the accuracy of HRM anyway.

[callmej]

I don't have a garmin, but use a Sigma bike computer. Your numbers, both in terms of calories burned and avg heart rate seem low to me, but maybe my signma is giving me higher numbers than actual. I just returned from a 20 mile ride, monderately hilly (I don't know the elevation gain, but I was huffing and puffing up a couple of the hills) , avg speed 15 mph - my avg heart rate was 144 and calories used 1159. I'm impressed with the length of your rides and your avg speed over those distances

[Triskeliongirl]

I think both your HR and cal numbers are low, compared to what I get on a similar ride on a very basic polar HRM. I don't know much about the garmin units, but on the polar you need to be sure to wet the contacts on the strap, so maybe you need to review that you put the HRM on correctly.

[Glory]

I don't know anything about the Garmin Edge but those numbers seem awfully low. I use a body bugg and granted I weigh a bit more than you but I burn roughly 500 calories on an hour ride and a much slower ride at that.

[marni]

I don't know anything about the Garmin Edge but those numbers seem awfully low. I use a body bugg and granted I weigh a bit more than you but I burn roughly 500 calories on an hour ride and a much slower ride at that.

I have a body bugg which is approximately accurate as long as I wear it on my ankle so the oscilator counter thingie actually works . I also wear a heart rate monitor from time to time

I think basically that it depends more on your level of fitness and the riding conditions (headwinds, hills, rough paving, stop and starts) than on anything else. I know that if I am doing a medium intensity, at at heart rate of 112- 115 bpm, (which is about 70% max for me) 15 mph ride in an average 10 mile head wind for about 1/2 of the ride distance, I will burn about 350 calories an hour.

If I push my speed to 17, get my heart rate up to 120-125 (80% max bpm ) in the same conditions, I will burn a good 400 calories an hour and if I do intervals with an occasional sprint it will go up to 500 calories an hour.

Obviously, since I am trained and prefer to ride distance and 3-4 hours at a time with no stops, my body has become efficient enough that I rarely burn more than 400-450 calories an hour. I am working on increasing cardio capacity so that I can ride faster(and hence further although that will mean coming up with some longer training rides) and at a higher heart rate and burn more calories, but I seem to be fated to be a max speed 17-18 miles an hour rider not matter how hard I ride or train. It is a little bit depressing but on the other hand, today on the elliptical trainer I managed to maintain a heart rate of 127 (85% max heart rate) for a full 60 minutes. Yay for me. By three minutes later, my heart rate was back down to 80 and at 5 minutes after the exercise ended it was back to it's normal 60 BPM.

My heart rate recovery is good and that's always good.

I just figure I do either a 300 or a 400 calorie and hour ride and plan accordingly mealwise.

I am one of those people who can eat a 500 calorie deficit daily and not lose weight, but that is a more a metabolism issue than a fitness issue. Undoubtedly some calories are sneaking in somewhere or I would be losing weight which I am not, just fighting earnestly to hold the line, but the sad fact is also that as you become better trained, your body becomes more efficient and the calorie burn decreases unless you increase intensity and or time. I am sort of at a delicately balanced point.

Anyway, do not forget to add in the miscellaneous factors, like wind, what gear are you riding in, the condition of the road, how often you stop, how long you stop, the temperature, the stress in your body and many others that I can't thing of right now. Evaluate your ride and work out an average calorie burn for hour and go with that. Skip the exact numbers unless you want to do a random check or need a baseline to change up your training.

[DarcyInOregon]

I use a Garmin Edge 705. The strap will read a low heart rate if the strap gets too loose or if the strap gets caught up in my bra band. What I do before every bike ride is after turning on the Garmin, I make sure the heart rate is showing on the display and that it shows a normal standing around fussing with the bike heart rate range, like in the 80s or 90s. If the heart rate reads lower, for example 35, then there I am out in the public, unzipping top layers and adjusting my bra and tightening up the chest strap. When the heart rate reads normal, then I put the Garmin on the bike and I am ready to go.

Most of my cycling friends use a Garmin and they are always posting links to their rides on Facebook. Over time I've seen enough Garmin data from different cyclists to know that for cyclists in my age range, male and female, our average heart rate on a ride is 120-140, depending on the elevation gain; I am age 57. Younger cyclists and/or cyclists who are not very fit may have a higher average heart rate.

I reviewed my ride history at Garmin Connect and for a ride that is 70-80 miles, my calories burned is between 2500 and 3000 and my average heart rate is around 130.

[nscrbug]

I think both your HR and cal numbers are low, compared to what I get on a similar ride on a very basic polar HRM. I don't know much about the garmin units, but on the polar you need to be sure to wet the contacts on the strap, so maybe you need to review that you put the HRM on correctly.

Yes, I do make sure to wet the contact points on the strap...and I also make sure that the strap is put on correctly - the GARMIN logo on the HR sensor facing right-side up...which it always does. I'm not sure what else I could possibly be doing wrong to get such low HR and calorie numbers...it's perplexing to say the least.

But I do feel a bit better knowing that you have all confirmed my beliefs of the low numbers. I'd be interested to hear if any other Garmin users are having similar experiences.

Linda

[azfiddle]

I use a Garmin 305. I rode 20.5 miles today, about 1 hour 22 min, and I burned about 800 calories. When rode 73 miles 2 weeks ago, 4 hrs 23 min, it said I used almost 3000 calories. Even if you're in great shape, you must be burning 500 calories an hour or more....

I can ask my DH who is the Garmin wizard around here. Did you set it up for your gender, weight etc?

[nscrbug]

I use a Garmin 305. I rode 20.5 miles today, about 1 hour 22 min, and I burned about 800 calories. When rode 73 miles 2 weeks ago, 4 hrs 23 min, it said I used almost 3000 calories. Even if you're in great shape, you must be burning 500 calories an hour or more....

I can ask my DH who is the Garmin wizard around here. Did you set it up for your gender, weight etc?

Yup, I sure did. It was fairly self-explanatory, so I don't think that I screwed anything up in doing so. That would be great if you could ask your DH...I can use any help I can get in sorting this issue out. Thanks!!

Linda

[OakLeaf]

When the battery in my HR strap is getting low, it'll read low. I need to replace mine right now, actually ... about halfway through this morning's run the readout dropped by about 70 bpm.

I think setting your HR zones correctly has a lot to do with the accuracy of the calorie reading as well, but I have no idea how to do that manually. The old Garmins (like my 301) had an algorithm that would figure zones for running. I suppose they must not have been that accurate, or they would've brought that feature forward into the newer models, but it really seemed to track my perceived exertion well. I just carried those zones over into later versions of GTC, and into the cycling side, even though I know that MHR for cycling is lower than running.


ETA - to AZfiddle, the 305 doesn't use the HR based calorie computations. For running it doesn't make that much of a difference, but for cycling it's huge. Three hundred calories per hour is probably ballpark for most women cycling at average effort. Five hundred maybe if you're solo, in a headwind, or on the ascending side of a mountain...

[Mr. Bloom]

My Garmin is closely in line with normal Calorie burn charts...it registers more with speed and climbing.

I plan on 60-70 calories per mile

[emily_in_nc]

Linda, have you tried taking your pulse manually while wearing the Garmin to see if the numbers are close? For example, stopping at the top of a hill when you feel that your heart is pounding or beating fast and taking your pulse at your wrist or neck while the Garmin is also taking it? You could try this at rest too. It's a simple test but may point out a discrepancy.

When I used to wear a Polar HRM, my max HR was usually around 180 or 190 and average HR around 150+ on a ride, and my calories burned about 400 per hour, and I'm little (<105 lbs). My DH, who weighs in the 150s, always burned a lot more calories than me on the same ride, according to his Polar, even tho his average HR was quite a bit lower than mine.

I agree with others, your numbers seem very low, though the calorie number is low b/c of the HR being low, so that's why I suggested verifying the unit is measuring your HR correctly. If it is, then you are very, very fit!

[OakLeaf]

Comparing your stopwatch pulse is a really good idea.

Do you have the new "premium" soft strap? Those are notorious ...