Polar FT4 HRM calorie burn overestimating?

Derf_Smeggle

Situation
Practice a martial art, Aikido. This is mostly cardiovascular activity. Typical class involves 5 minutes of structured warm-ups followed by periods of instruction where we are sitting for 2-3 minutes, then 7-10 minutes of practice. Wanted to see how many calories I burned during class in my dojo. Wore a Polar FT4 HRM for the 90 class this week.

This class wasn't ideal because there were a couple things we worked on that I had to slow down on to correct posture, stance, etc. I wasn't breathing nearly as hard as normal, and I have to assume my heart rate was lower. Will be wearing the monitor for a few more classes.

Age: 38
Sex: Yes please.. I mean, Male.
Height: 6'0"
Weight: 192.5 lbs
Max H/R: 179
(above from Digifit's age based online calculator, equation 6)
Zone Limits (65%-85%): 116 - 152
(above set by FT4 automatically)

Recorded Workout Time: 97 minutes
Avg H/R: 104
H/R high: 154
Time in Zone: 17 minutes

Question:
Calories Burned: 681?

Does that seem a bit high for a gross calorie burn?

A net calorie burn would take off 140 to 150 calories for 531 to 541 calories burned. I'm just not sure I buy that starting figure.

jaz050465

I'm not an expert but I know HRM rant accurate for everyday wear so maybe that's also true for the sitting about times. Have you thought of a Bodymedia Fit?

cmriverside

It's just a tool, and it's the best tool you have at your disposal I'm guessing.

It doesn't sound that outrageous for an hour and a half of average HR of 104.

Just use it. Since you apparently want to log calories burned, then use the tool. It is a good way to track your progress, regardless of whether it's "off" by a few calories one way or the other.

_Zardoz_

In all likelihood because of the stop start nature of what you're doing it won't be accurate.

sydneybeachgirl

I wouldnt say that an HRM gives awesome accuracy when doing marital arts...in my experience it works better in case of cardio exercises - that is cycling, running, rowing or high intensity workouts where the majority of the exercise is cardio (eg step ups, squats etc) then functional like boxing or lifting etc.. In my experience my HRM shows I burn hardly anything when I do martial arts which is not true as I am just as tired after it as an other class - or more. Nevertheless I think as long as you have configured your HRM accurately (and maintain the settings!) it is as accurate as it can be - it measures heart rate and assigns a cal burnt figure to it based on the HR and your bioparameters..

Derf_Smeggle

Thank you for the input so far, ladies and gents.

MinnieInMaine

Very likely an overestimate. HRMs aren't good for traditional strength training sessions for the very same reason. They're really only designed for steady state cardio, not that stop/start kind of workout. The only way to be more accurate would be for you to pause the HRM when you have those 2-3 minute stop periods. MIght be worth a try...

sassyjae21

Very likely an overestimate. HRMs aren't good for traditional strength training sessions for the very same reason. They're really only designed for steady state cardio, not that stop/start kind of workout. The only way to be more accurate would be for you to pause the HRM when you have those 2-3 minute stop periods. MIght be worth a try...

I agree

I have the same heart rate monitor. It is great for cardio, but it's pretty much worthless for strength training. Whenever I do circuit training, I start and stop it a lot when i'm lifing or doing abs. It's really only great for stready cardio.

Derf_Smeggle

MinnieinMaine,

Pausing the hrm during instruction was the next thing I was going to try! :happy:

The current method has been just guessing, and I want a little more accuracy. The hrm seems the best avenue to go and I've had this one sitting in a drawer for a few years. There is always that little learning curve to using new equipment and, while I realize this won't be exact, I'd like to know I'm in the ball park.

sydneybeachgirl

I do mixed workouts - lot of cardio with some small bursts of strenght training in between. I dont stop my HRM for the strength training (eg 2mins of deadlifts) as I am aware my HR is still up from the running I just did - bearing in my my transition time between these exercises is about 15-30seconds not a lot so my HR hitting the roof from the cardio doesnt go down to resting level ..My HRM says I burnt about 400+ cal in a 45min workout and given I am soaked with sweat (sometimes have to change COMPLETELY!) I think it is an accurate measurement..
however this being said this is workout is very different to a martial art class where there is not a lot of high intesity cardio and most of the time is spent practicing a technique..in my experience I work less in those classes in the sense that my HR is more stable in the lower region - never hiting the roof- so I dont end up sweating like a camel...I usually burn about 250+ in a 45min session of that...

dare2love81

That sounds like what my FT7 would report....maybe even a little on the low end. As others have said, it's just a tool...but having said that, using my HRM has allowed me to lose 60+ pounds based on the calorie burn it shows. *shrugs*

I don't know that any calorie burn estimator/tool is 100% accurate.

bugaha1

MinnieinMaine,

Pausing the hrm during instruction was the next thing I was going to try! :happy:

The current method has been just guessing, and I want a little more accuracy. The hrm seems the best avenue to go and I've had this one sitting in a drawer for a few years. There is always that little learning curve to using new equipment and, while I realize this won't be exact, I'd like to know I'm in the ball park.

Like someone said above I use mine as a workout tool and wouldn’t recommend pausing it because you’ll forget to restart it. Been there done that on a few long bike rides.