HRM -Calories Burned..accuracy ?

GlamNGlitter

So I just bought a HRM off of ebay and I was telling my husband that it counts the calories burned.
I do the Biggest Loser Bootcamp workout dvd so when I enter my exercise on here, I just put it under aerobics because dvd workouts aren't listed and I'm just using that as an estimate. So I really have no clue how many calories (more or less) I actually burn in a workout.

My question (and my husband's also) is how accurate are the HRM calories burned calculations?
Will it give me a better idea of how many calories I do really burn or is it just an estimate?:huh:

any thoughts, help, tips or ideas or anything is welcomed!

sanifrey

Your HRM will definately be more accurate then anything a machine or even MFP will estimate for you!!

What kind of HRM did you buy?? Does it have a chest strap to actually monitor your pulse?? Some are just wrist watches & they go by how you swing your arms. The ones with the chest strap will be the most accurate choice.

I love the BL workout dvd's too!! Enjoy!!

GlamNGlitter

its just a wrist watch... i bought a semi cheap one for now cuz i'm gonna save up to get that bl body bug thingy.. i want one so bad lol

this is the one i bought:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370277308854&ssPageName=STRK:MEWNX:IT

i think it's a no-name but as long as i get a better estimate of the calories i'm burning i'll be happy for now! :laugh:

jowily

HRMs calculate calories burned more accurately than guessing, averages, or the monitors on treadmills. Now granted....it is a calculation...and it depends on your accurate input of key data - age, gender, height, weight, etc. It then takes your exertion level, as recorded over your exercise, based on your heart rate...based on your your body stats it then calculates how many calories you burned during that workout. It's a combination of exact science - your heartrate over that time - and your body stats. It's certainly not 100% accurate as being hooked up to all sorts of equipment in a doctors office, but it's much more accurate than using the counter on your equipment - or just guessing.

By the way - as you lose weight - you need to adjust that on your HRM - as you lose weight you burn less calories doing the same exercise and you will be overstating your calorie burn...and if you are eating those calories you will be eating more than you should.

SHBoss1673

I'll just expand on john's response. He's right. There are numerous HRM's out there, and any decent HRM will actively measure your heart rate (instead of the cheap ones that only measure your heart rate when you push a button, those ones are essentially useless for accuracy).


BUT

the good HRMs will measure not only your heart rate (using a built in EEG), but also take into account the following other factors: Age, Weight, Height, Sex, VO2Max

You add all these factors in and you can have an extremely accurate measure of calories burned. Machines at the gym take into account Heart rate, weight (usually) and sometimes age (I've never seen one that asks for your sex, but I imagine they are out there). So for each missing dataum, you will have a factor of inaccuracy. Polar claims to be within 5% of calorimeters with their higher end products (the one that allow you to take a VO2Max test), I haven't seen their proof of this so I can't be sure, but I would imagine that's reasonable given the factors involved.

Just remember, VO2 max is a HUGE factor. It's the measure of the volume of oxygen in your blood, essentially how efficient your body is at delivering oxygen to muscles. Without oxygen, even muscles with plenty of glycogen will begin to fail because aerobic work cannot happen (aerobic means literally WITH OXYGEN) in the absence of oxygen.

I imagine they would even be more accurate if you could put in body fat % and possibly the results from other body tests, but I guess at some point it's diminishing returns. I.E. having a device that's accurate to within 5% and a device that's accurate to within 3.5% really means very little. Think about it like this, if you burn 500 calories, the different would be 7 calories, not really enough to pay an extra 50 or 100 bucks for.

tayner

I have a polar F11, and I love it. it has all the features, and IMO was one of the best things I invested in for my lifestyle change. As I have lost weight I have noticed that my calorie burn for the same perceived exertion level has went down, which makes perfect sense. I now have to work harder and longer to burn the same calories... but I dont mind

Azdak

The item you described is most likely a toy, not a real heart rate monitor. There is no way it can measure calories any more accurately than if you just made a number up.

I am the contrarian voice when it comes to HRMs and calorie counting. Not that I don't think they are worthwhile (I do)--I just don't think they are anywhere near as accurate as they claim (or as some people claim on their behalf).

It's one thing to achieve a high level of accuracy under research conditions where every HRM is set up exactly right, and with the exact right profile data, the activities are controlled, and the individual variances are distributed across a large group.

In the real world, most people have to estimate HRmax, estimate VO2max, and perform other activities in which the HR/VO2 relationship is not that strong. Just one example: In one study, doing a strength circuit at a 40% of 1 RM resistance elicited an average heart rate response of around 80% of HRmax. Normally, that would translate into about 70% VO2 max. However, measurements showed that actual VO2 was 39%-51% of VO2max. That's a 30+% difference right there. Other studies have shown that at lower intensities (40%-50% VO2 max) HRMs significantly underestimate calorie expenditure. On certain pieces of equipment, I consistently see a 25% increase in calories burned on my Polar F11 comparing the first half of a 45 min workout to the second half--even when workload is kept constant. I'm not working any harder, but my heart rate is increasing due to cardiovascular drift.

I would estimate that, in the real world, HRMs are off by 15%-20%. Personally, I think that's acceptable, given all the variables involved. For many activities--spinning, aerobic classes, etc--HRMs are the only really reliable option for counting calories.

I would also contend that some machines--treadmills, bikes, stairclimbers--that use ACSM metabolic equations or custom algorithms based on testing on the specific machines (e.g. Life Fitness) will give calorie readouts that are at least as accurate as a Polar HRM. Sometimes they may overestimate (esp running on a treadmill) where the Polar underestimates, but the degree of error will be similar. In that case, if you split the difference, you will probably be as accurate as can be without a metabolic cart.

I also think that the accuracy of HRMs will continue to improve--I would love to see the heart rate analytical technology of Polar or Firstbeat Technologies combined with the movement technology of the Bodybugg--now THAT would be the holy grail of HRMs!