Heart Rate/Calories Burned

lisag0109 wrote: »

Thought this info interesting and thought I'd share because this topic comes up so often and I'm a data/heart rate monitoring junkie!

Tried an elliptical interval experiment today to find out the difference in calories burned monitoring heart rate with a chest strap, my Garmin Vivosmart Hr (which monitors heart rate on wrist) and straight up calories burned on the elliptical.

I'm a 45yo female, so max heart rate is 175 based on age.
Moderate intervals keeping the machine between 150-170 strides per minute, varying speed and incline for one hour.

Elliptical readout:
615 calories burned

Chest strap info:
135 avg heart rate, 162 max heart rate
487 calories burned

Vivosmart HR info:
136 avg heart rate, 166 max heart rate
376 calories burned

Take it for what it's worth, but this is why so many people say eat back half your exercise calories and never believe what the exercise equipment tells you!

What I'd be asking myself in that case is which if any numbers of the three or the most accurate, and why. HR monitors in general do not work well for other than steady state exercise, and doing intervals would easily skew the numbers. Even for steady state stuff, the HR monitor and software can only be as potentially accurate as the data inputs it receives.

The same would apply to the machine. It might have different inputs, or available data. Depending on the type of machine, it could be inferior or superior data.

And in the case of all three, you'd also have to account for which ones are giving you gross calorie burn, and which ones are giving you net calorie burn. That alone makes up some of the differences at times, and though not huge for most single events over time could mess with a persons maintenance/loss/gain goals.

We have a machine with power measures. Power measures are absolute, though still subject to the flaws of calibration accuracy. But power is power, and more directly related to calorie burn than any other measure. HR would be a good indication if you could set the device up to scale with measured power in some way, as some of the new ones do. But without individual customization, HR alone really isn't all that great of a measure. Pumping efficiency, blood pressures, oxygen uptake, etc all factor in and as such HR at a given load isn't always the same person to person.

And in all cases with any body weight supporting exercise, something as simple as a difference in weight inputs could grossly skew even an otherwise accurate device.