How is heart rate related to calorie burn?

[TigerFish]

I started using a HRM early last fall. I am 58 now with a resting heart rate of about 65 with somewhat low blood pressure. Whenver I ride my average HR is generally somewhere around 125. My Maximum HR reached 161 once since I started using the HRM but the maximum averages 145. I ride a lot of hilly routes. When I ride on flats I really have to pump it out to get my HR over 110.

This is what I do not understand. All of the calorie calculations I see based on speed, time and distance show a total calorie burn almost double what the Garmin registers when I use the HRM. The Garmin actually estimates almost double the calories for similar rides when I do not use the HRM.

How does heart rate correlate to calories?

it seems that a person will register a higher total calorie burn regardless of their conditioning with a higher heart rate.

 

[sciguy]

The algorithm Garmin uses with heart rate to calculate Calories burned is widely recognized is rather useless. A power meter would give you a much better measure of Calories burned by using kilojoules of work done as a Calorie proxy.

Hugh

 

[Alex Simmons/RST]

How does heart rate correlate to calories?

it seems that a person will register a higher total calorie burn regardless of their conditioning with a higher heart rate.

While for an individual there is a loose correlation between HR and the rate of doing work (and hence energy metabolised), it is quite a variable relationship and of course varies wildly from person to person.

e.g. I'm pretty unfit and an hour of hard riding would metabolise only 2/3rds the calories that it would when I am very fit.

A pro cyclist could metabolise more than double the calories per hour than a weekend warrior might yet they might do so at the same or similar HR and body mass.

HR based energy estimations are good for some light comic relief.

 

[FrankDay]

Hr rate and calorie burn has a, generally, linear relationship while exercising aerobically. All that varies is the slope of the line as fitter athletes will be burning more calories for the same HR as less fit athletes.

 

[FrankDay]

Actually, as I have thought about this, HR and calories has more of an exponential relationship. This is because calories consumed has more to do with oxygen consumption and oxygen consumption is almost directly related to cardiac output (in the aerobic zone). Cardiac output is determined by multiplying HR and stroke volume. Stroke volume will tend to increase with increasing CO so calories burned will increase more than expected if just using HR as your metric. Want proof? Max HR is rarely more than 3-4 times more than resting HR but max O2 (calorie) consumption is way more than 3-4 times resting O2(calorie) consumption.

HR, by itself, is very good at determining whether calories consumed is more or less than before but pretty bad at determining the actual amount of calories burned.

 

[JayKosta]

I've learned a lot about how MY heartrate, power, calories, and 'relative perceived effort' (RPE) are inter-related by exercising on a fitness-center exercise bike that displays values for HR, Watts, Calories, as compared to my RPE.

For my outdoor cycling, I just use RPE, and try to watch how it relates to my speedometer.

For losing-weight via burning calories, you'll do better by riding for longer duration at a moderate 'exercise' pace. But of course the main item is to reduce the amount of calories that you eat.
Beware of justifying extra food as a 'treat' or 'reward' for having exercised!

Jay Kosta
Endwell NY USA

 

[elapid]

Here is the answer to your question, TigerFish:

http://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

 

[Alex Simmons/RST]

I've learned a lot about how MY heartrate, power, calories, and 'relative perceived effort' (RPE) are inter-related by exercising on a fitness-center exercise bike that displays values for HR, Watts, Calories, as compared to my RPE.

For my outdoor cycling, I just use RPE, and try to watch how it relates to my speedometer.

Yes, keep in mind that the correlation between HR and power output is typically stronger on an indoor trainer than when riding outdoors. The more naturally variable nature of outdoor effort and other stimuli means the two diverge somewhat more.

 

[FrankDay]

Yes, keep in mind that the correlation between HR and power output is typically stronger on an indoor trainer than when riding outdoors. The more naturally variable nature of outdoor effort and other stimuli means the two diverge somewhat more.

Really? Do you have any evidence to support this feeling?

 

[42x16ss]

Really? Do you have any evidence to support this feeling?

I'll go out on a limb and say that Alex's opinion is deduced from analysing 100's of power files from many athletes coached over the years. Since I started training with a PM myself I can say that I notice similar trends when riding with a strong tailwind and particularly into a raging headwind. Hills and riding in large bunches can throw things out as well.

 

[FrankDay]

I'll go out on a limb and say that Alex's opinion is deduced from analysing 100's of power files from many athletes coached over the years. Since I started training with a PM myself I can say that I notice similar trends when riding with a strong tailwind and particularly into a raging headwind. Hills and riding in large bunches can throw things out as well.

I asked if he had any evidence. By that I meant real evidence that there was a physical or physiological basis for saying:

correlation between HR and power output is typically stronger on an indoor trainer than when riding outdoors.

I suspect what he means is that power tends to be more variable outdoors, especially when riding in a pack, compared to trainer rides such that correlation between HR and power may not be very good, since both are "constantly" changing and HR changes lag changes in power somewhat. Intervals done on an indoor trainer would show poor correlation between HR and power also. This has nothing to do with being outdoors per se but only with the variability of the power seen outdoors compared to the typical trainer rides. For TT (constant" power) performances the correlation should be about the same whether done indoors or out. Highly variable power rides should show poor correlation whether done indoors or out.

The comment ignores the other metric always available to the athlete, RPE. And, for high variability rides RPE should correlate well with power - at least in experienced riders - whether the ride is of constant or highly variable power.

 

[elapid]

The comment ignores the other metric always available to the athlete, RPE. And, for high variability rides RPE should correlate well with power - at least in experienced riders - whether the ride is of constant or highly variable power.

Two highly subjective parameters (RPE and what is an experienced cyclist?) are unlikely to equate with power. But, then again, you don't believe in power as a stick anyway, do you Frank? So why compare RPE to power in the first place?

 

[FrankDay]

Two highly subjective parameters (RPE and what is an experienced cyclist?) are unlikely to equate with power. But, then again, you don't believe in power as a stick anyway, do you Frank? So why compare RPE to power in the first place?

Well, for one thing, power tells the rider absolutely nothing unless the rider is actually looking at the power meter. And, how accurate is it if the display is set to 3 or 10 or 30 second smoothing (isn't smoothing making it more like HR?)? RPE is always available to the rider. I think you will find that RPE and power actually correlate pretty well as a real time effort feedback tool.

One thing power does offer that RPE cannot is it can be used as a post-ride analysis tool.

 

[elapid]

Well, for one thing, power tells the rider absolutely nothing unless the rider is actually looking at the power meter. And, how accurate is it if the display is set to 3 or 10 or 30 second smoothing (isn't smoothing making it more like HR?)? RPE is always available to the rider. I think you will find that RPE and power actually correlate pretty well as a real time effort feedback tool.

One thing power does offer that RPE cannot is it can be used as a post-ride analysis tool.

Wrong thread - but an individual's ability to assess RPE is the huge and very subjective variable. Again, you need to visit your PM's Anonymous meeting to sort out your PM issues, but you still have not addressed the subjectivity of RPE and the subjectivity of how experienced does a cyclist need to be to accurately assess RPE. These are not measureable outcomes and this is where any argument you have will fail.

 

[FrankDay]

Wrong thread - but an individual's ability to assess RPE is the huge and very subjective variable. Again, you need to visit your PM's Anonymous meeting to sort out your PM issues, but you still have not addressed the subjectivity of RPE and the subjectivity of how experienced does a cyclist need to be to accurately assess RPE. These are not measureable outcomes and this is where any argument you have will fail.

I don't disagree that power is measurable. My question/argument has to do with the utility of the power meter to an athlete desiring to improve. What does one get for the cost? As near as I can tell all they get are some numbers that they can share with each other but from the point of view of improving there is zero evidence that this information results in improved outcome compared to those who use HR or RPE. So, until you folks of the power meter faith can come up with some data to show that there is an increased utility to an athlete using a power meter my argument doesn't "fail" because that is the argument. There may be some actual increased utility but as of yet there has been no demonstration of such. Once some increased utility is shown, if ever, then we can look at that benefit and compare it to the cost which, for most, is a substantial cost.

 

[elapid]

I don't disagree that power is measurable. My question/argument has to do with the utility of the power meter to an athlete desiring to improve. What does one get for the cost? As near as I can tell all they get are some numbers that they can share with each other but from the point of view of improving there is zero evidence that this information results in improved outcome compared to those who use HR or RPE. So, until you folks of the power meter faith can come up with some data to show that there is an increased utility to an athlete using a power meter my argument doesn't "fail" because that is the argument. There may be some actual increased utility but as of yet there has been no demonstration of such. Once some increased utility is shown, if ever, then we can look at that benefit and compare it to the cost which, for most, is a substantial cost.

Trolling, Frank. Take it to the PM thread.

 

[CoachFergie]

Trolling, Frank. Take it to the PM thread.

Make sure you report Franks trolling. He has been repeatedly told by moderators to not ask such stupid questions.

 

[FrankDay]

Trolling, Frank. Take it to the PM thread.

Ugh, my original post went to the linear relationship of RPE to O2 consumption. You were the one who brought up the subjective nature of RPE compared to a power meter. Simply a comment on your post.

 

[42x16ss]

I asked if he had any evidence. By that I meant real evidence that there was a physical or physiological basis for saying

How would 100's of power files from many various athletes NOT constitute evidence Frank? Because Alex hasn't bothered to take the time and compile a peer reviewed study?

 

[Berzin]

I've deleted FrankDay's and CoachFergie's posts and any others that quoted their posts.

This is a warning to both parties-cut it out or face a ban.

 

[FrankDay]

I've deleted FrankDay's and CoachFergie's posts and any others that quoted their posts.

This is a warning to both parties-cut it out or face a ban.

I can understand deleting the posts that were off the original topic (even though most threads tend to drift a bit) but it seems a tad severe to delete my first two posts on this thread that went directly to the question posted about how HR correlates to calories. :-(