Calories burned (HR vs machine w/ HR)

skudera27

Hi everyone. My wife got me a Polar HR monitor for my birthday in October, which I've been using most times I go to the gym. The machines at my gym can pickup the reading from my monitor automatically, which I really like.

I wanted to compare how my HR monitor calculates calories compared to the machines I used that were reading my HR monitor. I biked 6 miles and ran 3 miles. After my workout, the HR monitor said about 850 calories, while the two machines combined only got to about 650.

So my question is - which number of calories burned should I feel more comfortable going with? My guess is the machines since it's reading my true heart rate and knows the type of workout I'm doing. I feel if that's the case, then what good is the HR monitor?

sassyjae21

Your HR monitor doesn't have a chest strap? I would be more inclined to go with the HR monitor just because it is truly taking your actual HR and it knows how hard you are working. But i agree, sometimes I wonder if mine overestimates too because it's ALWAYS higher than the machine. I never truly go with either one. I use the average of the numbers (somewhere in between). It makes me feel better lol

mccindy72

The heart rate monitor will be more accurate than the machine, which is just calculating based on numbers you put in, the level you're on and the speed you're moving at. There is a very good website that will tell you how to calculate calories burned by HR, and also how to calculate your VO2 max, which is calculating how your body uses oxygen and burns calories. There's also an area to calculate your net calories, which deducts the calories your body would have burned anyway just by being alive, so you know exactly how many calories your workout burned. Machines only calculate gross, and HR monitors do too. The site is here:

http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx

Dgydad

I'm using a Garmin Forerunner 110 w/ the optional chest-strap heart rate monitor. If your Polar is similar, it uses your age and weight in addition to your heart rate to compute calories burned. Since it is passive and customized, I'd rely on that. The machines introduce variables; do they use the same formula as your Polar? Are they properly maintained? Are they interpreting the HR monitor signal correctly? Also, the Polar goes wherever you go; that means if you use it for guidance, you will have consistency. Just MHO....

sassyjae21

The heart rate monitor will be more accurate than the machine, which is just calculating based on numbers you put in, the level you're on and the speed you're moving at. There is a very good website that will tell you how to calculate calories burned by HR, and also how to calculate your VO2 max, which is calculating how your body uses oxygen and burns calories. There's also an area to calculate your net calories, which deducts the calories your body would have burned anyway just by being alive, so you know exactly how many calories your workout burned. Machines only calculate gross, and HR monitors do too. The site is here:

http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx

This is great thank you!

agthorn

650 actually sounds closer (general estimates are 40 calories per mile biking and 100 calories per mile running). Are you sure your heart rate monitor has all your correct information? Whenever I use my HRM and the machines are also picking up the signal (I also have a Polar) they come out pretty close to each other.

skudera27

My HR monitor does have a strap, which is how I'm getting my HR. The machines are picking up my HR based off the reading coming from the monitor I'm wearing. I guess I really should read up more on how these things work...because if I'm running on a treadmill at 6mph, and the treadmill is reading my true HR via my monitor, I would think that's more accurate than just having my HR monitor pickup my HR and not know what type of exercise I'm actually doing.

And FYI, it's a Polar FT7

dswolverine

I have the same issue except the machine always says I burn more calories than my HRM. I have a Polar FT4 with the chest strap. The machine always is above my HRM by at least 100 calories or more. I go with the lower number- I would rather be underestimating than overestimating.

bigtwagner

The heart rate monitor will be more accurate than the machine, which is just calculating based on numbers you put in, the level you're on and the speed you're moving at. There is a very good website that will tell you how to calculate calories burned by HR, and also how to calculate your VO2 max, which is calculating how your body uses oxygen and burns calories. There's also an area to calculate your net calories, which deducts the calories your body would have burned anyway just by being alive, so you know exactly how many calories your workout burned. Machines only calculate gross, and HR monitors do too. The site is here:

http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx

I totally agree with this!!!

MinnieInMaine

HRMs are also generally more accurate because they have more of your personal data to use in the calculation. Cardio machines might ask for weight and age but there's no mention of gender or height which are pieces of data your HRM would have (assuming you set it all up correctly). The more data, the more accurate the calculation.

Typicaly cardio machines overestimate but they're not all made/programmed the same. In y gym, the ellipticals tend to overestmate by about 30%, the treadmills are fairly spot on, the stationary bikes underestimate by almost 30%. And this is even with them reading my heart rate from my HRM's chest strap transmitter! However, your cardio machines might be a completely different brand, model, etc so their estimates may be completely different.

FYI, I use a Polar FT4.

One more point - V02 max calculators online aren't that great from what I've been told. More info in this article
http://sportsmedicine.about.com/od/anatomyandphysiology/a/VO2_max.htm

skudera27

HRMs are also generally more accurate because they have more of your personal data to use in the calculation. Cardio machines might ask for weight and age but there's no mention of gender or height which are pieces of data your HRM would have (assuming you set it all up correctly). The more data, the more accurate the calculation.

That's something that didn't click - height and gender. That definitely makes a big difference.

I guess I just don't fully understand how the HR monitor can accurately calculate calories burned if it just has HR, age, weight, height, gender - I would of thought it needs to know the workout as well (i.e. running, swimming).

With that being said - hypothetically, if someone took some type of pill that just had their heart racing fast for say an hour, would the HR monitor calculate similar calories burned than doing an hour of exercise with same HR level?

LeslieC1970

I would go with your HRM. As far as I know, you would need to put in your weight, height, age, etc into the machine and have your chest strap on for the machine to be accurate.

chezjuan

HRMs are also generally more accurate because they have more of your personal data to use in the calculation. Cardio machines might ask for weight and age but there's no mention of gender or height which are pieces of data your HRM would have (assuming you set it all up correctly). The more data, the more accurate the calculation.

That's something that didn't click - height and gender. That definitely makes a big difference.

I guess I just don't fully understand how the HR monitor can accurately calculate calories burned if it just has HR, age, weight, height, gender - I would of thought it needs to know the workout as well (i.e. running, swimming).

With that being said - hypothetically, if someone took some type of pill that just had their heart racing fast for say an hour, would the HR monitor calculate similar calories burned than doing an hour of exercise with same HR level?

HRMs are good for calculating calories burned for steady-state cardio (such as running at 6 MPH for 1/2 hour, cycling, etc.), as there is a correlation between HR and calories burned in those instances. The specific type of exercise does not really matter as long as it is steady state. HRMs are not good for resistance training, HIIT, or other non-steady-state forms of exercise for the exact reason you list above - the HRM assumes that you are doing something predictable, not random.

HRMs use a calculation to determine the calories, so the accuracy is dependent on the variables that you input (height, weight, sex, VO2 Max (if you can either input it or have the HRM calculate it). The exercise machines at the gym use similar calculations, but they assume "average" VO2 Max rather than request your specific number (at least I have never had a machine ask for my VO2 Max). For me, the machines and the HRMs give close numbers, which were also generally in line with calculations when I used the ShapeSense calculator to double-check (generally they are +/- 25 calories or so).

All that said, they are still only estimations so if you are trying to use the calories burned to determine how many calories you can eat back after your exercise, you may want to go with the lowest number you get to ensure that you don't overestimate the burn.

skudera27

Thanks everyone for the valuable information - I've learned a lot today

howardheilweil

I have the same issue except the machine always says I burn more calories than my HRM. I have a Polar FT4 with the chest strap. The machine always is above my HRM by at least 100 calories or more. I go with the lower number- I would rather be underestimating than overestimating.

Same here.

OP, I suggest that you go with the lower number, which in your case is the machine. You would definitely rather err on the side of understating your burned calories. Good luck!