Are heart rate monitors trustworthy in calorie burn?

Shaselai

So i did a zumba class today and my average BPM is 153 going as high as 175. 153 is supposed to be 82% of my max HR if going by the 220 -age formula. My question is the app spits out that i burned ~1050 calories and i checked on 2 calculators online which takes into my weight, height, duration, average BPM and spitted out very similar numbers with one spitting out a lower "net" number because it subtracted out the calories during that time the body uses for "normal maintenance" so its net calorie of 940ish is the calories lost by exercise. My question is how accurate is all this? The HRM is a chest piece so i guess it is pretty accurate but then it comes down to the formula? I am very happy if the number of calories burned is close to whats shown but i dont want to be too happy when reality i burned like 400 calories...

HerkMeOff

They are about as close as you're going to get.

SLLRunner

Only for steady state cardio, which Zumba is not.

DavPul

ain't nobody burning no 1000 calories in no zumba class

PikaKnight

Only for steady state cardio, which Zumba is not.

^This

ain't nobody burning no 1000 calories in no zumba class

And ^this.


Some interesting reads in regards to HRMs if interested:

http://www.myfitnesspal.com/topics/show/1044313-this-is-why-hrms-have-limited-use-for-tracking-calories

http://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472

heybales

Sadly for women there is huge bell curve for accuracy, and even the 220-age for HRmax you have better chance of being 10 bpm away from that then in range.

Even nice Polar with lab measured stats entered had issues. Without those stats but HRM measured or calculated ones - really bad.

http://www.myfitnesspal.com/topics/show/459580-polar-hrm-calorie-burn-estimate-accuracy-study


But you can test yours for how close in accuracy it is to really best estimate. And if you can do the test reaching a running speed that gets your HR up to that same 153 for about 15-20 min, you'll know what the real calorie burn was at that HR.

http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is

Sadly as commented though, that workout wasn't steady-state, so avgHR was actually inflated above what it needed to be.
You'll notice that on the treadmill test, as you increase pace to get HR up, you'll see it go up to certain level, and then drop back down in 1-4 min depending on your fitness to where it really needs to be, meaning for the entire time prior to drop back it was inflated above where it needed to be.

And don't do the test after having a double espresso or meds that get your HR up, nor after the class, but prior.

Keepcalmanddontblink

What is Zumba? Also how long is the class? If its 30 minutes or more, and if someone like me (large person) was doing the class, than maybe you could be burning that many calories. I can burn almost 500 calories walking for an hour but my husband only burns about 200.

fatcity66

I don't know about Zumba, but I have burned 900-1000 calories in a 60 min spin class...of course, that is with no breaks...Also, I weigh over 200 lbs.

ninerbuff

How long was the class?

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness industry for 30 years and have studied kinesiology and nutrition

zoeysasha37

I really can't imagine that doing zumba could produce a 1000 burn. I think that measurement would be for steady state, not zumba

heybales

If you weighed 225 lbs and ran 6 mph for 60 min that would be almost 1100 calories gross, like HRM would report.

From the Zumba classes I've seen ones doing, there is great variation in intensity from one person to another, but at some point I'm betting the motions just don't allow getting more intense even if you wanted to.

Now that is the type of exercise where you do get more efficient with your movements and burn less as you become better at it, so adding ankle and hand weights would make sense to increase intensity back up. (I comment on that because of ones saying it happens with jogging or biking or other where the weight and pace is the same, then it's not true).

kdeaux1959

I'd suggest taking the lesser number (the net rate number). HRMs work best for steady state cardio... They do poorly for strength training burn from what I understand.

DavPul

How long was the class?

About two hours and 32 minutes, I reckon.

Did you get promoted?

Shaselai

no it was an hour long class. This is actually not official "Zumba" but called Sensazao (you can see youtube videos) which is a VA dance company. I say zumba because it is very zumba like except:
1. no slow songs
2. no breaks unless teaching a new step
3. high intensity - lots of jumping, kicking, squatting etc.
4. local zumba instructors borrow their songs/steps in their own classes (thats how i came to know about them).

i am 250 right now.
I guess even if this ends up being burning 400calories it was still a lot of fun!

heybales

no it was an hour long class. This is actually not official "Zumba" but called Sensazao (you can see youtube videos) which is a VA dance company. I say zumba because it is very zumba like except:
1. no slow songs
2. no breaks unless teaching a new step
3. high intensity - lots of jumping, kicking, squatting etc.
4. local zumba instructors borrow their songs/steps in their own classes (thats how i came to know about them).

i am 250 right now.
I guess even if this ends up being burning 400calories it was still a lot of fun!

That is different than, and long.

If it feels the same as running 5 mph level, then it's likely very close, and actually realistic.

http://www.exrx.net/Calculators/WalkRunMETs.html

But you would indeed only eat back the NET, not the gross.

scorpio516

60 minutes @ 250 lbs. 1000 KCal is believable. A little high probably, but not out of the realm of possibility.
If you were 150 lbs, then it would be BS (1000 KCal/hr @ 150 is VERY hard work!)

HOWEVER, 220-age IS wrong. It's correct for almost no person in the world. If you are basing your calorie consumption on calories burned via heart rate, then you need to find out what your max HR is. A cardiologist would find that. Your GP might. Or you can do a TT.

DavPul

At that weight it's very possible for a male to burn that many calories in an hour. I'm still thinking it's unlikely on zumba, but it does move to the realm of the possible

ninerbuff

How long was the class?

About two hours and 32 minutes, I reckon.

Did you get promoted?

Yep. Fear me now.:laugh:

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness industry for 30 years and have studied kinesiology and nutrition

ninerbuff

no it was an hour long class. This is actually not official "Zumba" but called Sensazao (you can see youtube videos) which is a VA dance company. I say zumba because it is very zumba like except:
1. no slow songs
2. no breaks unless teaching a new step
3. high intensity - lots of jumping, kicking, squatting etc.
4. local zumba instructors borrow their songs/steps in their own classes (thats how i came to know about them).

i am 250 right now.
I guess even if this ends up being burning 400calories it was still a lot of fun!

It's possible then. I probably wouldn't count 1000 calories just to be safe. I'd rely more on like 800 calories.

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness industry for 30 years and have studied kinesiology and nutrition

Shaselai

Sadly for women there is huge bell curve for accuracy, and even the 220-age for HRmax you have better chance of being 10 bpm away from that then in range.

Even nice Polar with lab measured stats entered had issues. Without those stats but HRM measured or calculated ones - really bad.

http://www.myfitnesspal.com/topics/show/459580-polar-hrm-calorie-burn-estimate-accuracy-study


But you can test yours for how close in accuracy it is to really best estimate. And if you can do the test reaching a running speed that gets your HR up to that same 153 for about 15-20 min, you'll know what the real calorie burn was at that HR.

http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is

Sadly as commented though, that workout wasn't steady-state, so avgHR was actually inflated above what it needed to be.
You'll notice that on the treadmill test, as you increase pace to get HR up, you'll see it go up to certain level, and then drop back down in 1-4 min depending on your fitness to where it really needs to be, meaning for the entire time prior to drop back it was inflated above where it needed to be.

And don't do the test after having a double espresso or meds that get your HR up, nor after the class, but prior.

I know i get sweaty pretty much within 2nd-3rd song which is within 10 minutes. if you see some of the videos it is pretty intense, even more so with so many others nearby.
I will check out the treadmill test later today and bring back some results later to see how my HRM compares to it. Coincidentally i have my general checkup next week so maybe if possible i will try to get my max HR checked?

djprice_69

I have the Polar FT4, and it seems to be working great. I've done comparisons when simply walking between my HRM and my old pedometer, and they matched up so close it was scary. I've also tried run/walk intervals on a treadmill while holding onto the hand-grips so the machine could track it as well, and once again they matched up almost verbatim. I've been using my FT4 every time I work out ever since and I'm quite pleased with it.

Kevalicious99

Accurate ... No. Better than nothing ... yes.

For example .. walked with HRM on, like walking is probably as simple as it gets. But HRM said 1998 cal burned (just over 10 miles) .. but in reality it was more like 500.

So .. you can judge for yourself.

elizashopsalot

I'm a huge fan of Zumba. It's one of the few exercises I don't dread. I started Zumba about 30 pounds ago, and was burning around 425 calories for a 50 minute class. Now that I've been doing it for a few months and 30 pounds lighter I'm burning around 375 for a 50 minute class. I'm well over 200 lbs. If you use the calorie estimate pre-programmed into MFP, their estimate is way higher than my HRM, so I always use the lower HRM figure because I figure it's more conservative. As one of the other members stated, your intensity can vary based on the instructor and the day. I assume since I've had good results using the HRM, it's better than nothing. I don't eat back all my calories either. I always try to stay under by at least 200 on Zumba days.

heybales

I know i get sweaty pretty much within 2nd-3rd song which is within 10 minutes. if you see some of the videos it is pretty intense, even more so with so many others nearby.
I will check out the treadmill test later today and bring back some results later to see how my HRM compares to it. Coincidentally i have my general checkup next week so maybe if possible i will try to get my max HR checked?

Sweat isn't a good indicator of effort, unless you are comparing to yourself and have noted the differences in sweating with temp and humidity and effort. Some people cool really well and never need sweat stage. I start putting on the workout clothes and my body preps by starting to sweat, so I better not think about it too much either.

I doubt general checkup will be setup for HRmax test.
But you can ask if it appears safe enough for you to test it on your own.

Then you can do your own puke test, I mean, max test.

http://www.myfitnesspal.com/blog/heybales/view/testing-hrmax-vo2max-with-max-treadmill-test-643927

BrianSharpe

If you weighed 225 lbs and ran 6 mph for 60 min that would be almost 1100 calories gross, like HRM would report.

If you use RunnersWorld's formula for net calories expended....

225 x.63 x 6 = 850.50

as a direct result of the exercise.

HRMs vary considerably depending on the algorithm they use. My Garmin 610 is pretty close (it estimated 707 cal for my 5 mile run this morning, using the RW formula around the 600 mark)

Shaselai

ok so i did the walking test and my HRM records 241 but the calculator site records 271.... so there is 11% error. but the HRM calculated less than burned so what does that mean? does that mean at higher heart rate i could be +/- 11% accuracy?

heybales

ok so i did the walking test and my HRM records 241 but the calculator site records 271.... so there is 11% error. but the HRM calculated less than burned so what does that mean? does that mean at higher heart rate i could be +/- 11% accuracy?

So your HRM isn't aware of the fact you are fitter than your BMI is leading it to believe.
So while your weight may still be higher than healthy range, your fitness level is better than expected.
You are burning more than it knows.
Basically, it sees a low HR and assumes you didn't work hard.
But in reality, you are fit enough your HR doesn't have to go as high to do the hard work.

The upper levels depends on how well you have trained up there.
You might picture it as 2 lines on a graph.
The reality line of best burn up above. And almost straight line going up until you hit anaerobic level.
Your HRM reported line is down 11% below, and it could hold equal distance all the way up, it could come closer, it could drop more.

But as time goes on and you become more fit, more than the weight drops, that 11% will start to widen.
It's easier to get fit faster than to lose weight. In fact the extra weight almost forces it to happen faster.

So was that testing walking speed, or the HR you get with Zumba?
If walking, the higher HR is next one. Then you'll know your line.
How long was the test?

And, as you become more fit - you'll need to retest in a month. Not only for less weight, but more fit, lower HR at same level.
So note your stats.
Next time out you'll try to hit the same HR, and can see your progress in the increased pace or incline required to obtain it again. And the higher calorie burn for that HR.

So if your HRM said you burned 5000 calories in a week down at that level, you know you burned about 550 more, or 78 average more daily. Not too bad.

Shaselai

Thanks for the detailed analysis. I followed the instructions of doing 10 min warmup till 120 then kept at a pace for 20 min. So does the 11% only affect exercises that are constant not like zumba where there could be breaks etc?

heybales

Correct.

non-steady-state exercise always has some amount of inflated HR until it drops back down by some number of beats. Number and how long it takes depends on your fitness level.

So as you were warming up for your test, you may have been increasing the pace to get to 120 bpm.

And what you'd normally find is you increase it by say 0.5 mph, HR jumps up to 130, and then after a few minutes it lowers back down to 120. So the 120 is what the body needs for that speed. It was inflated by 10 bpm for those few minutes just because of a change in intensity.

Same as when you stopped the treadmill and stood there - did the HR drop back to the normal needed standing HR of say 80 instantly?
No, it took several minutes. So for that entire time it was inflated up to 40 gradually back to none until 80 was hit. Which was all that was truly needed for that intensity.

Now picture your traditional Zumba workout or anything with changing intensities.
HR jumps up above what is really needed for that level of intensity, and just as it's about to lower to where it really needs to be, you change intensity again.
If you went down, it's going to drop - slowly, but really be inflated that whole time. If you went up, it's going to jump higher than it needs to be for however long until it lowers. But then you go and changed intensity again, so it never happens.

So nothing but inflated values during the whole time, and as you can see, some quite big.
In fact probably the worst offender is interval training.
Push really hard and HR reaches max you can get for 15-30 sec, and then you walk. Normally only need say 90 bmp walking, but it never gets down to that level, it gradually decreases and by the time 60 sec of rest is up, it only got down to 120, so inflated the whole time. Since the rest is 4 x the hard part, the avgHR still reads kind of low, but it should have been even lower.

If you could somehow get the real average HR actually needed during your whole routine, then the 11% higher would apply to whatever avg was found and calorie burn given to it.

That's another fun fitness test on treadmill.
After warmup, increase pace by big jump, see what high HR is reached fast, and then how long until it drops back down to a HR it is steady with. How much time to drop and how big a drop - more fit is smaller of both.
Same as when you stop a workout at some high HR, and you stand there, how far does the HR drop in say 1 min, and then 2 min. That's another sign of improved fitness as it drops farther. Some HRM's even do that one for you when you press the stop button.

So the HRM can indeed be very useful. Just not the accurate tool for calorie burn many think it is.
But for your workouts, if you know you are doing the same intensity, you should notice as you get more fit the avgHR for the whole time drops.
Because the HR is able to move faster up, and likely faster down, and lower in general, just showing you have gotten fitter.

Shaselai

it is interesting that you mentioned HIIT. Even though the HR reading might not be accurate like you said but the workout itself is beneficial for its increase in fat burning and VO2max right?

contingencyplan

As long as you're performing aerobic activity (moderate intensity sustained for long durations, such as joing for jogs) they are pretty accurate. For higher intensity work that spikes the heart rate (such as sprints, weightlifting, or HIIT), though, no.