HRM wrangling: accurate calories?

[DuncanBlkthrne]

After using my Polar RS100 for about a year and a half or so, I've finally come to the conclusion that it's grossly inaccurate when it comes to reporting Calories I'm burning during on-bike workouts and during crosstraining exercises (it reports way too high). I'm planning on getting a PowerTap some time this fall (then I can use kiloJoules instead), but in the meantime (and still for crosstraining), I need to accurately track Calories burned, in order to not over- or under-feed myself too much. I have much excess bodyfat I need to lose, but I need to keep up with my training schedule, and I don't want to create an excessive calorie deficit.

What methods are people using to estimate calories burned?

 

[Alex Simmons]

a power meter

 

[iliveonnitro]

a power meter

This.

 

[tonyzackery]

A powermeter is better, but it's limited by the fact that it only measures enery expenditure while you're working (pedaling). When you're coasting (think rides with alot ascending and descending) you're still burning calories and a HRM takes this into acount.

 

[iliveonnitro]

A powermeter is better, but it's limited by the fact that it only measures enery expenditure while you're working (pedaling). When you're coasting (think rides with alot ascending and descending) you're still burning calories and a HRM takes this into acount.

Two things. One: what is your energy expenditure when you are not working? By its very definition: 0.

Two: no, it doesn't. A HRM does not account for calories you burn when not pedaling. Even if it did (hypothetically), would you then plan on subtracting those calories from your BMR, since you are effectively eliminating those hours of the day from your calculations?

 

[tonyzackery]

Two things. One: what is your energy expenditure when you are not working? By its very definition: 0.

Two: no, it doesn't. A HRM does not account for calories you burn when not pedaling. Even if it did (hypothetically), would you then plan on subtracting those calories from your BMR, since you are effectively eliminating those hours of the day from your calculations?

Do you burn calories when you're sitting on the couch? When you're not "working" on the bike, you're coasting. Can you agree with that?

The HRM takes into a number of factors when it calculates energy expenditure - age, heart rate, weight, fitness level, gender, et al. Your heart is still beating when you're not pedaling, right?

 

[iliveonnitro]

A powermeter is better, but it's limited by the fact that it only measures enery expenditure while you're working (pedaling). When you're coasting (think rides with alot ascending and descending) you're still burning calories and a HRM takes this into acount.

Do you burn calories when you're sitting on the couch? When you're not "working" on the bike, you're coasting. Can you agree with that?

The HRM takes into a number of factors when it calculates energy expenditure - age, heart rate, weight, fitness level, gender, et al. Your heart is still beating when you're not pedaling, right?

So you'll subtract that number from your BMR since the HRM already factors that in?

Show me proof.

 

[tonyzackery]

So you'll subtract that number from your BMR since the HRM already factors that in?

Show me proof.

Does it really matter to you that much?! Hell, I'll do whatever you want me to do, and when you want me to do it. You want me to subtract something from whatever - no problem...

LOL! Did I initially respond to this thread to defend the merits of HRMg and their accuracy, or lack thereof, of calorie expenditure? Nope.

The powermeter is better, but it still only measures energy expenditure while you're pedaling, and on some of my rides I'm not pedaling 100% of the time...maybe you pedal 100% of the time on all your rides - good on you...

 

[Wlfdg]

I've finally come to the conclusion that it's grossly inaccurate when it comes to reporting Calories I'm burning during on-bike workouts and during crosstraining exercises (it reports way too high).

What are you basing this on? Just curious?

 

[iliveonnitro]

What are you basing this on? Just curious?

I attached a picture of 2 rides I did. My powertap and my Garmin Edge were both recording on my bike.

1. Approximately 46mi. I forgot to turn on the Garmin for the first 6.5 miles.
Garmin calories: 2461
PowerTap cal's: 1558
difference: 37% -- even with a 6.5mi discrepancy it reads 37% high

2. Approximately 52mi, same deal with the Edge (I use it for directions, not training anymore)
Garmin calories: 3326
PowerTap cal's: 1794
Difference: 46% -- even with the 3mi discrepancy.

So, on average, you can assume a HR monitor over-estimates by ~40-50%.

How do I know these numbers don't account for "burning energy while not working?" Because I wasn't even wearing a HR monitor strap. HR isn't a requirement in HR monitors to calculate calories burned.

 

[tonyzackery]

How do I know these numbers don't account for "burning energy while not working?" Because I wasn't even wearing a HR monitor strap. HR isn't a requirement in HR monitors to calculate calories burned.

????
So what variable metric would a HRM with calorie expenditure calculation capability use to determine if you are running/cycling/etc... versus simply sitting on the toilet? Seems like common knowledge, but with your statement above the question begs to be asked...try googling "how do heart rate monitors calculate calories burned". I already did.

I must presume your Garmin is set-up to receive power info from the PT hub in order to calculate energy expenditure absent the HR info. Apparently Garmin and Saris use different algorithms to calculate energy expenditure.

 

[DuncanBlkthrne]

What are you basing this on? Just curious?

In part I'm basing it on reports from other HRM users.
Also in part my own research into the subject: even though Polar claims it's accurate to within +/-10%, and even though it takes height, weight, age, gender, and resting heart rate into account, there are still assumptions being made by the formulas and algorithms it's using.
Also, the people who do testing in the sports medicine lab I go to say that it estimates on the high side, as an incentive to people to keep exercising; they say that a power meter is more accurate because it's measuring actual work being done, even if that is ALSO an estimate.
Finally, I've been using a HRM for about 1.5 years now and have NOT been able to lose the excess BF I'm carrying around, even though I keep meticulous records of calories and macronutrients and have maintained (on paper, mind you!) a steady calorie deficit.
Besides which, does it really sound believable to burn 2000 calories to ride 30 miles on a more or less flat course?

I can't keep fooling around with inaccurate data that holds me back from my goals. My weight is probably my biggest single limiter, and I can't address that issue without accurate data.

 

[DuncanBlkthrne]

I attached a picture of 2 rides I did. My powertap and my Garmin Edge were both recording on my bike.

1. Approximately 46mi. I forgot to turn on the Garmin for the first 6.5 miles.
Garmin calories: 2461
PowerTap cal's: 1558
difference: 37% -- even with a 6.5mi discrepancy it reads 37% high

2. Approximately 52mi, same deal with the Edge (I use it for directions, not training anymore)
Garmin calories: 3326
PowerTap cal's: 1794
Difference: 46% -- even with the 3mi discrepancy.

So, on average, you can assume a HR monitor over-estimates by ~40-50%.

How do I know these numbers don't account for "burning energy while not working?" Because I wasn't even wearing a HR monitor strap. HR isn't a requirement in HR monitors to calculate calories burned.

OP here,
For the most part: Winner, winner, chicken dinner! That's what I've been told, power meters are more accurate, and I'm more than happy to shell out for a PowerTap and have a wheel built around it.

So far as "not wearing the HRM strap" and it still recording calories burned: You've got a Garmin, I've got a Polar. I can't say I've tried running it without the strap across my chest (why would I?) but I'll try that and see what it does. If it is recording calories even with no HR measured, then so far as I'm concerned it's credibility for anything other than just HR and timekeeping go straight into the toilet!

 

[DuncanBlkthrne]

OP here,

I've discovered that Polar makes HRMs (RS200, RS400, and above) that allow manual input of VO2max, which I believe would make it's calorie estimation more accurate; anyone care to weigh in on that?

 

[tonyzackery]

Finally, I've been using a HRM for about 1.5 years now and have NOT been able to lose the excess BF I'm carrying around, even though I keep meticulous records of calories and macronutrients and have maintained (on paper, mind you!) a steady calorie deficit.

I can't keep fooling around with inaccurate data that holds me back from my goals. My weight is probably my biggest single limiter, and I can't address that issue without accurate data.

Here's my suggestion for you - you will cut bodyfat if you are able to stick consistently with the protocol :
1. cut your carb intake 50% from its present level and replace with mostly lean protein and polyunsaturated fats. high glycemic carbs immediately after rides only - low glycemic at other times
2. low intensity rides only
3. maintain a low (<500) daily caloric deficit

Your body will need to burn the stored fat as fuel.
I am not suggesting this is the only method to cut bodyfat, but it will work and is my best reasonable suggestion.

Give it a go...what have got to lose? A bunch of bodyfat!

 

[RHR38]

OP here,

I've discovered that Polar makes HRMs (RS200, RS400, and above) that allow manual input of VO2max, which I believe would make it's calorie estimation more accurate; anyone care to weigh in on that?

My coachee visits couple of times per year in labtests to chek his threshold levels and watts (this lab is trusted and tests mainly high level athletes). It looks to me that Polar CS600 own 'Fitness Test' underestimates VO2max around 4 ml/kg, but we use manual input. Change in VO2max changes calorie estimation at least in this Polar model.

 

[swampy1970]

I can't keep fooling around with inaccurate data that holds me back from my goals. My weight is probably my biggest single limiter, and I can't address that issue without accurate data.

Yes you can. Eat slightly less, ride more, sleep more, avoid alcohol.

Make whatever time you have on the bike "quality time" - if you only have less that 90minutes per most sessions then hard 20 to 25 minute intervals with 5 minutes rest. Repeat 2 or 3 times. I find this a sure fire way of losing weight and as posted in other thread I can't seem to lose weight as easily if I stick to the more "traditional" method or riding at a fast tempo pace for several hours.

There's no need to turn basic bike training into something that resembles a scientific project or accountancy. If you don't put in the "quality time" then you'll never expend the energy at a sufficient rate...

 

[swampy1970]

I attached a picture of 2 rides I did. My powertap and my Garmin Edge were both recording on my bike.

1. Approximately 46mi. I forgot to turn on the Garmin for the first 6.5 miles.
Garmin calories: 2461
PowerTap cal's: 1558
difference: 37% -- even with a 6.5mi discrepancy it reads 37% high

2. Approximately 52mi, same deal with the Edge (I use it for directions, not training anymore)
Garmin calories: 3326
PowerTap cal's: 1794
Difference: 46% -- even with the 3mi discrepancy.

So, on average, you can assume a HR monitor over-estimates by ~40-50%.

How do I know these numbers don't account for "burning energy while not working?" Because I wasn't even wearing a HR monitor strap. HR isn't a requirement in HR monitors to calculate calories burned.

Get the two units set up properly, ie to record the same distance, average speed and max speed and then come back with the numbers.

 

[DuncanBlkthrne]

Here's my suggestion for you - you will cut bodyfat if you are able to stick consistently with the protocol :
1. cut your carb intake 50% from its present level and replace with mostly lean protein and polyunsaturated fats. high glycemic carbs immediately after rides only - low glycemic at other times
2. low intensity rides only
3. maintain a low (<500) daily caloric deficit

Your body will need to burn the stored fat as fuel.
I am not suggesting this is the only method to cut bodyfat, but it will work and is my best reasonable suggestion.

Give it a go...what have got to lose? A bunch of bodyfat!

I still have one event to do before my riding season is done, and making drastic and perhaps ill-advised changes to my diet before then might be disasterous -- that's what I have to lose. ;-)

This thread is about HRMs and their calorie-counting accuracy. Thanks for the comment anyway.

 

[tonyzackery]

I still have one event to do before my riding season is done, and making drastic and perhaps ill-advised changes to my diet before then might be disasterous -- that's what I have to lose. ;-)

This thread is about HRMs and their calorie-counting accuracy. Thanks for the comment anyway.

Ouch! LOL! Try to help a guy out and he shyts on me...LOL! And then he thanks me for the comment...LOL!