GPS watch Calories burned during running; how accurate?

PaytraB

I'm just curious. I don't really track my calorie burns (other than to post them on MFP) but have noticed that the calories on my GPS watch seem low at times. I found an on-line calculator (http://www.runnersworld.com/tools/calories-burned-calculator) and compared todays run.
I ran 8K and walked 1.17K (warm up & cool down) and according to my GPS watch I burned 504 calories in the 81 minutes.
Using the calculator, running 8K in 67:36 minutes (no walking was included in the calculation) burned 609 calories.

81 minutes (mixed activity) = 504 calories
67 minutes (straight running) = 609 calories

Which would you believe is the most accurate?
My watch went into "low battery" during my run. Would that make a difference in how it calculates calories?

I'm just curious as to how accurate the watch may be.

timeasterday

I tend to go with whatever my Garmin tells me. I typically burn just a tad under 100 calories per mile (given a typical recovery run pace without big hills). The Runner's World calculator overestimates my calories by about 15-20%.

Your GPS estimate of 504 calories sounds pretty close to my experience with two different Garmin models. The low battery alert should not affect things. It will keep recording.

pmur

I wore my polar ft4 yesterday to track exactly that. I did a 10k run with a mile of warm up/cool down combined and the polar said 740 cals whereas the mapmyrun app gave it as 830. I generally think the polar was more accurate. I lost all my weight tracking activity with polar. Not sure about the gps watch though.

PaytraB

Thanks! I use my Garmin calories as well and it sounds as if that's the count to trust.
The other day was a lower-than-expected calorie burn day because so much of my run was uphill (somehow I expect more calories to be burned for an uphill run), which got me looking at other calculators. I suppose that since the uphill runs are slower than the level-terrain runs, the calorie burns are about the same per minute.
I'm just going to keep on running and having fun. Thanks again!

KathleenKP

My Garmin has a setting for "lifetime athlete" - AKA "efficient and not burning as many calories". Or you can choose regular athlete, that has a higher burn rate.

rduhlir

Both of my GPS watches are pretty close when it comes to calories burnt. I have a Garmin 210 and a TomTom Runner.

PinkNinjaLaura

Plexgut are you using a HRM chest strap with the GPS watch, or just the watch?

PaytraB

Laura, just the watch. I think that's close enough for what I use it for.
Lately, I've been paying more attention to the calories burned on each workout and beginning to wonder why some days have more calories than others for pretty much the same distance. Hills don't seem to matter to the GPS watch, matter of fact, the days I run my hill I burn fewer calories (although I feel as if I should burn more) but I also slow down (+3-4 minutes; hill is approx. 2K long before it levels off) so speed must be the factor.
I think I would burn more calories running on flat terrain at a faster speed than running the same distance uphill at a slower speed. My head tells me that if the distance is the same, the calories burned should be about the same.

I also wonder about the algorithms used in the different calculator sites. Some must calculate just exercise calories, while others calculate exercise + normal breathing/living calories for the time spent exercising?

PaytraB

My Garmin has a setting for "lifetime athlete" - AKA "efficient and not burning as many calories". Or you can choose regular athlete, that has a higher burn rate.

I laughed, Kathleen, at the thought of calling myself an athlete. :laugh: It's a nice thought, though.