HRM Accuracy

vlc1979

This morning someone told me that HRM's are not that accurate? WHAT??? The news sent me into shock.

I googled the topic and I am finding mixed information.

I have a Polar FT7

What is everyone's opinions on this?

mcdonl

I have two... one is a cheapo $30 HRM from walmart and the other is a $20,000 lifepak ECG/Defibrilator I store in my ambulance.

They both give me the same HR when I tested them.

Runnermadre

I'm not saying they have pin point accuracy, but they must be close, because I lost over half of my weight using the readings from my HRM. Just make sure that all of your information is entered correctly, and you should be good to go!

Marquettedominos

From what I have read is that HRM's that use a chest strap are considered medical grade equipment. They are much more accurate than the wrist ones or the contacts that are on a machine.

_SusieQ_

if you have one with a chest strap, I would say it's about as accurate as you can get without professional, medical grade technology. If it's just one with the watch and no chest strap, you have a lot more room for error.

having said that, IMO, an HRM is still always going to be more accurate than estimates you get on here in the Exercise database.

aimeeturner

Mine is 100% accurate. I have a Polar FT7.

freshstart4me

if you have one with a chest strap, I would say it's about as accurate as you can get without professional, medical grade technology. If it's just one with the watch and no chest strap, you have a lot more room for error.

having said that, IMO, an HRM is still always going to be more accurate than estimates you get on here in the Exercise database.

i agree with auntie for sure. my HRM and the machine had 125 calorie difference today...eff the machine count!!

shaj316

I have an FT7 too (just got it a couple of days ago). It jives with the readings I get if I put my hands on sensors on treadmills and bikes at the gym. It also matches my expectation for when I'm at rest, so I have no reason not to believe it.

Perhaps the person who told you this was using a faulty one?

Jeepinmom4

I have two... one is a cheapo $30 HRM from walmart and the other is a $20,000 lifepak ECG/Defibrilator I store in my ambulance.

They both give me the same HR when I tested them.

this makes me feel good,I question my walmart chepo hrm all the time!

lynheff

In my experience The polar F2 I have with chest strap is very accurate. The treadmill handles are not. The reason I got the polar hrm in the first place is that the treadmill gave me very erratic readings--some as high as 220. I thought I was either in fantastic shape for my age or on the verge of a stroke. It bothered me for a few weeks so I went out and got the FT2. I guess it should have been a clue when changing my hand position changed my heart rate by 30 bpm.

abbie017

They aren't 100% accurate, but they are the closest estimate that you'll get!

tomomatic

I have an FT7. I assume it's more accurate than the cardio machine, which is getting it from your hand. (The heart is over HERE!!!!)

Are you referring to the calorie counting portion?

shaj316

I have an FT7 too (just got it a couple of days ago). It jives with the readings I get if I put my hands on sensors on treadmills and bikes at the gym. It also matches my expectation for when I'm at rest, so I have no reason not to believe it.

Perhaps the person who told you this was using a faulty one?

erickirb

This morning someone told me that HRM's are not that accurate? WHAT??? The news sent me into shock.

I googled the topic and I am finding mixed information.

I have a Polar FT7

What is everyone's opinions on this?

If the calcualiton embedded in the HRM has an assumed V02 Max close to what yours actually is they are quite accurate, up to 80-90%. If the V02 Max is wrong they can be 70-80% accurate, which are both pretty good estimates. That being said the calculation also assumes you are doing steady state cardio. If you are doing strength training or circuit training it won't be as accurate. Same goes for HIIT, but with HIIT it will be closer than strength training or circuit training.

MinnesotaManimal

I sure as heck hope it is right, I have an FT-7 as well and have been eating back 50-75% of my excercise calories over my daily goal based on those numbers. and yes I have been losing still.

erickirb

Mine is 100% accurate. I have a Polar FT7.

HR read may be 100% accurate, but the cals burned are based on an equation so it may or may not be that accurate (usually 70-85% accurate, as a portion of caloric burn cannot be accounted for based on age, weight, height, gender, HR, or V02 Max, which are all the inputs into the equations)

CeejayGee

Just make sure you subtract out your resting rate calories. If it says you burnt 400 calories on your watch, you have to subtract out the amount you would have burnt just by sitting on your couch doign nothing.

fitby2012

I trust my HRM enough (Sportline from Walmart) to eat only a portion of my exercise calories back if I am hungry. I totally trust the food calculator though :bigsmile:

erickirb

Just make sure you subtract out your resting rate calories. If it says you burnt 400 calories on your watch, you have to subtract out the amount you would have burnt just by sitting on your couch doign nothing.

This too, so if you burn 1.5 cals/min based on your maintenance cals you would have to back out 45 cals for a 30 minute workout.

otr12

Treat your FT7 like it's 100% accurate.

It's close enough to provide you with good results. Don't make yourself crazy trying to identify inaccuracies.

tomomatic

Just make sure you subtract out your resting rate calories. If it says you burnt 400 calories on your watch, you have to subtract out the amount you would have burnt just by sitting on your couch doign nothing.

This too, so if you burn 1.5 cals/min based on your maintenance cals you would have to back out 45 cals for a 30 minute workout.

Correct me if I'm wrong, I assumed that MFP had built in the BMR into the calculations that it was using for target calories based on what we set for our activity level. (sedentary, active, etc) I assumed that bmr was taken care of at that point.

So I guess the question is does MFP take bmr (maintenance cals) into account? I don't think our HRM's calculate bmr.

erickirb

Just make sure you subtract out your resting rate calories. If it says you burnt 400 calories on your watch, you have to subtract out the amount you would have burnt just by sitting on your couch doign nothing.

This too, so if you burn 1.5 cals/min based on your maintenance cals you would have to back out 45 cals for a 30 minute workout.

Correct me if I'm wrong, I assumed that MFP had built in the BMR into the calculations that it was using for target calories based on what we set for our activity level. (sedentary, active, etc) I assumed that bmr was taken care of at that point.

So I guess the question is does MFP take bmr (maintenance cals) into account? I don't think our HRM's calculate bmr.

Neither MFP or HRM's account for that. The cals burned you see are total cals burned for that period of time, not extra cals on top of maintenance. so you should back out maintenance, not BMR (as you would not be in a coma if you weren't working out), to get cals burned due to exercise as opposed to cals burned during the duration of exercise. The longer you workout and the heavier you are the more important this becomes.

kennethmgreen

Treat your FT7 like it's 100% accurate.

It's close enough to provide you with good results. Don't make yourself crazy trying to identify inaccuracies.

Agreed. No matter what you do, it's going to be an estimation. You try to narrow the margin of error, but you have to accept the fact that unless you are hooked up to machines and being monitored and fed by a trained staff, you aren't likely to ever get 100% accuracy.

First off, I assume the OP is talking about calories burned with regard to accuracy. Heart Rate accuracy is pretty reliable with the HRM watches. It is generally accepted that you need at least a chest strap to get a reliable reading, including calorie reading. You gotta do what works for you. But definitely don't drive yourself crazy. I had a Timex, but was suspicious of the calorie readings (seemed high). Sure enough, I returned it and got a Polar FT7 and the Polar reports a lower calorie number. You can usually check the accuracy by comparing some samples online. MFP exercise estimates are very general and won't match up to everyone.

Not everyone subtracts our BMR either. I have heard claims that the watches account for this. I am not sure what the best choice is there. I don't wear my HRM all the time. What about when I walk from my desk to the bathroom multiple times per day? What about going up the stairs? I don't count these, but am surely burning more calories than BMR burn.

But really, don't get too hung up on the utmost precision. 70-80% accuracy might not sound all that great, until you consider how many of us enter our food. Are you weighing every item to the gram? Do you break down every meal by ingredient? If not, the Polar FT7 readings should be fine. The difference in food diary entries (calories reported vs. actual calories) are likely far more variable than the calories burned readings on my Polar.

kennethmgreen

Neither MFP or HRM's account for that. The cals burned you see are total cals burned for that period of time, not extra cals on top of maintenance. so you should back out maintenance, not BMR (as you would not be in a coma if you weren't working out), to get cals burned due to exercise as opposed to cals burned during the duration of exercise. The longer you workout and the heavier you are the more important this becomes.

I'm not 100% convinced this is true. I should contact Polar. I have a friend (here on MFP) that reported wearing his Polar HRM while skiing and while sitting down on the ski lift, the calories burned number stayed still while riding the lift - no calories were being burned during that activity. That seems like resting HR is taken into account. I guess I could try a similar experiment.

erickirb

Neither MFP or HRM's account for that. The cals burned you see are total cals burned for that period of time, not extra cals on top of maintenance. so you should back out maintenance, not BMR (as you would not be in a coma if you weren't working out), to get cals burned due to exercise as opposed to cals burned during the duration of exercise. The longer you workout and the heavier you are the more important this becomes.

I'm not 100% convinced this is true. I should contact Polar. I have a friend (here on MFP) that reported wearing his Polar HRM while skiing and while sitting down on the ski lift, the calories burned number stayed still while riding the lift - no calories were being burned during that activity. That seems like resting HR is taken into account. I guess I could try a similar experiment.

Polar HRM's will count cals while sitting still, he must have had an error (I use the FT4) and in the manual they state that the calculation is total calories burned. Some other Brands may back them out but Polar does not.

solpwr

HRM's are very accurate at giving you an accurate reading of your heart rate.

The most accurate estimations of calorie count would be a sophisticated HRM in combination with clinical testing to establish your maximum heart rate, and your VO2 max, which is the quantification of your aerobic fitness (your body's ability to utilize oxygen).

A body bugg is also a very useful tool for quantifying calories burned, especially for total expended in all activities during your day.

The Polar FT40 and FT60, as well as several other high end Polar HRM's will have the functionality to enter in maximum heart rate and VO2 max, and even have a fitness test embedded in the HRM that is the best submaximal test of VO2 max available. (It uses R wave to R wave variability during rest.)

The less expensive models still provide a reasonable accounting of calories burned, as long as you've set up the inputs properly. Gender, weight, age, and fitness level? I don't know if they have that last one or not frankly. The higher end ones have that.

As far as whether they count your BMR, not in my experience with my HRM. I'm the guy Kenneth referred to riding the chairlift. When my HR returns close to resting, the calorie count quits running up, at least on mine. I would suggest sitting on the couch and watch some TV and see what it does. I would put money on the fact that it will read 0, or so small it is inconsequential.

I've left mine on before and driven down the mountain after a day of mountain biking. Zero calories expended.

I hope to really nail down a lot of this stuff. I'm planning to do a Maximal Oxygen Consumption Test this winter.

vlc1979

Thanks everyone for the great informtation. I should have clarified I was talking about the accuracy of the calories burned..

The margin of error in all of this seems to be about the same so I figure most of it will probably equal out in the wash....

aimeeturner

Mine is 100% accurate. I have a Polar FT7.

HR read may be 100% accurate, but the cals burned are based on an equation so it may or may not be that accurate (usually 70-85% accurate, as a portion of caloric burn cannot be accounted for based on age, weight, height, gender, HR, or V02 Max, which are all the inputs into the equations)

My HRM has all of those pieces of data stored in my settings.

solpwr

Mine is 100% accurate. I have a Polar FT7.

HR read may be 100% accurate, but the cals burned are based on an equation so it may or may not be that accurate (usually 70-85% accurate, as a portion of caloric burn cannot be accounted for based on age, weight, height, gender, HR, or V02 Max, which are all the inputs into the equations)

My HRM has all of those pieces of data stored in my settings.

Which one do you have?

erickirb

Mine is 100% accurate. I have a Polar FT7.

HR read may be 100% accurate, but the cals burned are based on an equation so it may or may not be that accurate (usually 70-85% accurate, as a portion of caloric burn cannot be accounted for based on age, weight, height, gender, HR, or V02 Max, which are all the inputs into the equations)

My HRM has all of those pieces of data stored in my settings.

all of those only account for 80-85% of caloric burn, as not all of calories burned can be explained by those inputs. The other 15-20% is estimate so you will probably be 90-99% accurate when all is said and done.

bassettpig

Regarding the question of whether HRMs automatically subtract your basal metabolic calories (the calories you would burn just sitting on the sofa), no, they definitely do not. Go ahead and contact Polar; it's always good to get the info for yourself, but no, they do not.

For a female my size and age, it only amounts to about a calorie per minute of exercise difference, so if I'm doing a half hour of easy jogging, I don't worry about subtracting out that 30 calories, not that big a deal. However, if I'm taking a 60-mile bike ride on Saturday AM and I'm going to be out there for 4 hours, we are talking about 240 calories, a way more significant amount, and that I WILL definitely subtract out.

Some people don't bother w/subtracting the calories at all and do fine too--so I guess YMMV.