This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Calories burned during a run

Former Member over 9 years ago

I've only recently started using my 235 for running and am puzzled by a low reported value for calories after finishing a run.

I recently plodded round 4.39km (2.73 miles) in 30:58 (yes, I'm very slow!) but the watch and app are telling me that the associated calorie burn is only 62 calories. While I believe from other threads that the calories shown do not include BMR over the same period, this still seems like an abnormally low figure to me. I weigh 108kg (238 pounds) and have all of my vital stats programmed into the system.

I'm guessing that maybe I'm misunderstanding something here because I haven't heard any other similar reports from anyone else.

Can anyone help?

0 Former Member over 9 years ago

One other thing which I haven't mentioned so far is that all of my runs have been with a chest-worn heart rate strap. I've been using this simply because I thought I'd get better results and was looking to avoid the much reported cadence lock issue. The actual raw numbers it's giving me looks very much as I'd expect but I wonder if there's a possibility that something else in the data is influencing my results.

On my next run I'll use the inbuilt optical sensor and see if anything changes.

0 Former Member over 9 years ago

Well, it looks like it may have been some kind of incompatibility with the heart rate strap after all.

I've just been out on a short run using the inbuilt optical sensor and my numbers now look good.

3.22 km in 20:25. Average heart rate 152. Calories 324. Training Effect 3.6.

It's also given me a VO2max estimate for the first time. It says 41 which seems quite high to me but as it's only got this one run to go on so far, I'd imagine it'll settle down eventually.

https://connect.garmin.com/modern/activity/1010099677

0 Former Member over 9 years ago

Sofaklecks, it looks like your experience is very similar to mine. You say that your data looked fine initially but has now changed. Had you changed any particular setting in the meantime?

I had installed the latest beta firmware (2.41) and it went back to correct calculation (1 run so far). Although I doubt this was the real reason. Maybe it was just the reboot or some re-initializing coming along with the install process.

btw, I also use a chest strap (Garmin). But for the very first run I used the built-in sensor and got a VO2-Max right then. May, now that you have that score, you can try the strap again.

0 Former Member over 9 years ago

I've pretty much confirmed now that my low calorie burn figures and minimal TE figures were due to some kind of incompatibility between the 235 band the heart rate strap I was wearing.

The strap I was wearing was a MYZONE belt which claims to transmit simultaneously by both Bluetooth and ANT. On the face of it, the 235 was certainly picking up heart rate data from the MYZONE and the figures looked correct but for whatever reason the final calorie burn and TE numbers were way off the mark.

My first run using the 235's built-in optical sensor looked much better - a sensible calorie burn and a meaningful TE. It also gave my a VO2max value for the first time - albeit one that looked a bit higher than expected. Hopefully VO2max will settle down with more data.

I then tried using the 235 with the MYZONE again to check my theory that there was an incompatibility there and sure enough I got another calorie burn figure of about 10% of the expected value and a TE of just over 1.

I've now dusted down my old Garmin heart rate strap that came with my 610 and tried a few runs with the 235. The data I'm getting all looks good.

I guess the moral of the story is, don't trust all heart rate straps to be compatible with the 235 just because they say they're ANT compatible.

0 gpb11 over 9 years ago

Great report.

I'm guessing the strap you used was sending bad HRV/RR values, as I believe that data is used for VO2max, TE, and calorie estimates. Since we don't really see that data itself it'd be tough to know that's the problem. Again just a guess.