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So some of you will have noticed that I have been running quite a bit recently and in March of this year I upped the ante with the purchase of a Suunto Ambit with accompanying heart rate monitor which claims to be able to calculate the calories burned.
So, after another run last night I checked the total since March and I now have a tally of over 25000 calories burned.
Quite apart from being an amazing figure in itself I'm curious to know, from those in the know, as to the relative accuracy of these things.
So, after another run last night I checked the total since March and I now have a tally of over 25000 calories burned.
Quite apart from being an amazing figure in itself I'm curious to know, from those in the know, as to the relative accuracy of these things.
In reply to TheDrunkenBakers:
Does the gizmo know how much you weigh, if it does it probably isn't too far out, if not it will use an average based on what it does know. I take it you have run 200-250 miles in that period.
Does the gizmo know how much you weigh, if it does it probably isn't too far out, if not it will use an average based on what it does know. I take it you have run 200-250 miles in that period.
In reply to TheDrunkenBakers: 100 cals per mile is a rough guide
In reply to The New NickB:
Yes it does, you enter your vitals into the online doozy including age, weight, sex etc.
368.8km registered since March 6th when I acquired it.
> (In reply to TheDrunkenBakers)
>
> Does the gizmo know how much you weigh, if it does it probably isn't too far out, if not it will use an average based on what it does know. I take it you have run 200-250 miles in that period.
>
> Does the gizmo know how much you weigh, if it does it probably isn't too far out, if not it will use an average based on what it does know. I take it you have run 200-250 miles in that period.
Yes it does, you enter your vitals into the online doozy including age, weight, sex etc.
368.8km registered since March 6th when I acquired it.
In reply to IainRUK:
Which is slightly worrying.
E.g. It registered 9.96km last night with 825 cals burned.
On your calcs that would be 6.18 miles therefore 618 cals.
Can the device be 25-30% out or am a missing something.
> (In reply to TheDrunkenBakers) 100 cals per mile is a rough guide
Which is slightly worrying.
E.g. It registered 9.96km last night with 825 cals burned.
On your calcs that would be 6.18 miles therefore 618 cals.
Can the device be 25-30% out or am a missing something.
In reply to TheDrunkenBakers: about bang on.. 100 cals / mile is a conservative estimate.. and makes for easy calculations.. that would be 23,000 cals.. 110 is more accurate which is 25,000
In reply to TheDrunkenBakers:
Easy 9km run this morning, 178m of ascent. 762 calories burned. Sounds in line with what Iain said.
However, my watch (Garmin Forerunner 405) uses my heart rate, and tells me in the history that I've only burned 603 calories (even closer to Iain's 100kcal/mile rule of thumb). If I upload the same data to Garmin Connect, or Fetch Everyone (I don't use them any more) then I get varying figures again.
I think it demonstrates that it's pretty difficult to accurately measure calorie expenditure in something as complex and varied as the human body, but using HR and some personal stats is the least bad technique we have. I would have thought that with all the factors it can't take into account then it could easily be 25-30% out.
I'm only 65kg and 173cm (10st, 5'8) so probably don't burn as much per mile as somebody taller and heavier.
I don't pay too much attention to the number to be honest, apart from when I've come back from a long run and decide I'm justified in eating my own bodyweight in food to make up the lost 3.5k calories
> (In reply to IainRUK)
> [...]
> Can the device be 25-30% out or am a missing something.
> [...]
> Can the device be 25-30% out or am a missing something.
Easy 9km run this morning, 178m of ascent. 762 calories burned. Sounds in line with what Iain said.
However, my watch (Garmin Forerunner 405) uses my heart rate, and tells me in the history that I've only burned 603 calories (even closer to Iain's 100kcal/mile rule of thumb). If I upload the same data to Garmin Connect, or Fetch Everyone (I don't use them any more) then I get varying figures again.
I think it demonstrates that it's pretty difficult to accurately measure calorie expenditure in something as complex and varied as the human body, but using HR and some personal stats is the least bad technique we have. I would have thought that with all the factors it can't take into account then it could easily be 25-30% out.
I'm only 65kg and 173cm (10st, 5'8) so probably don't burn as much per mile as somebody taller and heavier.
I don't pay too much attention to the number to be honest, apart from when I've come back from a long run and decide I'm justified in eating my own bodyweight in food to make up the lost 3.5k calories
In reply to TheDrunkenBakers:
How much do you weigh?
Another rule of thumb (metric) similar to Ian's is assume your weight (eg 70kg) as kcal (i.e. 70) and multiply by kilometres run.
So a 10km run for a 70kg runner = 700 kcal.
> (In reply to IainRUK)
> [...]
>
> Which is slightly worrying.
>
> E.g. It registered 9.96km last night with 825 cals burned.
>
> On your calcs that would be 6.18 miles therefore 618 cals.
>
> Can the device be 25-30% out or am a missing something.
> [...]
>
> Which is slightly worrying.
>
> E.g. It registered 9.96km last night with 825 cals burned.
>
> On your calcs that would be 6.18 miles therefore 618 cals.
>
> Can the device be 25-30% out or am a missing something.
How much do you weigh?
Another rule of thumb (metric) similar to Ian's is assume your weight (eg 70kg) as kcal (i.e. 70) and multiply by kilometres run.
So a 10km run for a 70kg runner = 700 kcal.
In reply to Stuart (aka brt):
I'm about 75kg - 5'9" aged 37 and a half. Stocky build.
> (In reply to TheDrunkenBakers)
> [...]
>
> How much do you weigh?
>
> Another rule of thumb (metric) similar to Ian's is assume your weight (eg 70kg) as kcal (i.e. 70) and multiply by kilometres run.
>
> So a 10km run for a 70kg runner = 700 kcal.
> [...]
>
> How much do you weigh?
>
> Another rule of thumb (metric) similar to Ian's is assume your weight (eg 70kg) as kcal (i.e. 70) and multiply by kilometres run.
>
> So a 10km run for a 70kg runner = 700 kcal.
I'm about 75kg - 5'9" aged 37 and a half. Stocky build.
In reply to TheDrunkenBakers:
Unless you are super efficient or inefficient only your weight matters, pace does even make much difference, ie you burn as much per mile walking as doing 6 minute miles. Hills can make a difference.
Unless you are super efficient or inefficient only your weight matters, pace does even make much difference, ie you burn as much per mile walking as doing 6 minute miles. Hills can make a difference.
In reply to TheDrunkenBakers: Your heart rate monitor will be more accurate than any of the guesstimates above if you have inputted your details correctly (age, weight, sex, etc). It takes into account the effort over the time (based on your heart rate). So saying x Cals/hour is ok as a rough guide, but it doesn't take into account how much effort you are putting in, weather conditions, time of day, terrain, speed, etc. Your HRM will be the most accurate way that you can calculate your calorie consumption. Also you'll fimnd that it will be more accurate if you run for longer. They are not good for 5 mins exercise, weight training etc as they have limited data (heart rate activity) to put into their fancy algorithms.
Your HRM will be the most reliable, accurate method of calculating calorie consumption for you, if used correctly and consistently.
Your HRM will be the most reliable, accurate method of calculating calorie consumption for you, if used correctly and consistently.
In reply to Martin1978:
No one has said anything about calories per hour. A GPS device will calculate the energy required to transport a known weight at a fairly predictable efficiency, this is going to be more accurate than a HRM.
No one has said anything about calories per hour. A GPS device will calculate the energy required to transport a known weight at a fairly predictable efficiency, this is going to be more accurate than a HRM.
In reply to The New NickB:
That's fascinating.
So, if I walked 1 mile in 25 mins I would burn the same cals as if i ran this in 7 mins? To the untrained, that seems quite counter intuitive.
The benefits gained for the run would be a. that the heart is given a better workout and that you could get the post exercise pint quicker.
> (In reply to TheDrunkenBakers)
>
> Unless you are super efficient or inefficient only your weight matters, pace does even make much difference, ie you burn as much per mile walking as doing 6 minute miles. Hills can make a difference.
>
> Unless you are super efficient or inefficient only your weight matters, pace does even make much difference, ie you burn as much per mile walking as doing 6 minute miles. Hills can make a difference.
That's fascinating.
So, if I walked 1 mile in 25 mins I would burn the same cals as if i ran this in 7 mins? To the untrained, that seems quite counter intuitive.
The benefits gained for the run would be a. that the heart is given a better workout and that you could get the post exercise pint quicker.
In reply to The New NickB:
I'll check the manual but as the HRM is twinned with the GPS capabilities of the watch I would think the algorithms factor this in.
> (In reply to Martin1978)
>
> No one has said anything about calories per hour. A GPS device will calculate the energy required to transport a known weight at a fairly predictable efficiency, this is going to be more accurate than a HRM.
>
> No one has said anything about calories per hour. A GPS device will calculate the energy required to transport a known weight at a fairly predictable efficiency, this is going to be more accurate than a HRM.
I'll check the manual but as the HRM is twinned with the GPS capabilities of the watch I would think the algorithms factor this in.
In reply to The New NickB: read calories/km as well then.
I disagree about the GPS. I have run the same route on a sunny day, and again in snow with strong, freezing winds. My average heart rate was significantly higher, and therefore so was my calorie burn. How would the GPS know this? It doesn't take into account the effort required to maintain that speed.
The OP asked how accurate their HRM was for calories burned. Answer, very accurate (based on the info inputted into it, as given above).
I disagree about the GPS. I have run the same route on a sunny day, and again in snow with strong, freezing winds. My average heart rate was significantly higher, and therefore so was my calorie burn. How would the GPS know this? It doesn't take into account the effort required to maintain that speed.
The OP asked how accurate their HRM was for calories burned. Answer, very accurate (based on the info inputted into it, as given above).
In reply to TheDrunkenBakers:
It is pretty simple physics, the only difference would be very minor differences in efficiency (walking is marginally more efficient) clearly the benefits of running to beyond just calorie loss, but you can obviously burn more in the same time period running.
> (In reply to The New NickB)
> [...]
>
> That's fascinating.
>
> So, if I walked 1 mile in 25 mins I would burn the same cals as if i ran this in 7 mins? To the untrained, that seems quite counter intuitive.
>
> The benefits gained for the run would be a. that the heart is given a better workout and that you could get the post exercise pint quicker.
> [...]
>
> That's fascinating.
>
> So, if I walked 1 mile in 25 mins I would burn the same cals as if i ran this in 7 mins? To the untrained, that seems quite counter intuitive.
>
> The benefits gained for the run would be a. that the heart is given a better workout and that you could get the post exercise pint quicker.
It is pretty simple physics, the only difference would be very minor differences in efficiency (walking is marginally more efficient) clearly the benefits of running to beyond just calorie loss, but you can obviously burn more in the same time period running.
In reply to Martin1978:
He asked about a GPS/HRT device. The HRT without the GPS is much less accurate than the other was around.
He asked about a GPS/HRT device. The HRT without the GPS is much less accurate than the other was around.
In reply to Martin1978:
Cals/mile and cals/hour are very different measures the second being much less accurate.
Cals/mile and cals/hour are very different measures the second being much less accurate.
In reply to Martin1978:
I should qualify that the Ambit is a GPS watch and so all measures are downloaded including ascent/descent so I'm assuming that this is calculated in the output.
> (In reply to The New NickB) read calories/km as well then.
>
> I disagree about the GPS. I have run the same route on a sunny day, and again in snow with strong, freezing winds. My average heart rate was significantly higher, and therefore so was my calorie burn. How would the GPS know this? It doesn't take into account the effort required to maintain that speed.
>
> The OP asked how accurate their HRM was for calories burned. Answer, very accurate (based on the info inputted into it, as given above).
>
> I disagree about the GPS. I have run the same route on a sunny day, and again in snow with strong, freezing winds. My average heart rate was significantly higher, and therefore so was my calorie burn. How would the GPS know this? It doesn't take into account the effort required to maintain that speed.
>
> The OP asked how accurate their HRM was for calories burned. Answer, very accurate (based on the info inputted into it, as given above).
I should qualify that the Ambit is a GPS watch and so all measures are downloaded including ascent/descent so I'm assuming that this is calculated in the output.
In reply to TheDrunkenBakers:
NO walking and running are very different in terms of efficiency. Once you are running the evidence suggests a linear relationship between pace and energy usage, which means a mile burns **about** the same.
There is some variation on pace with kcals burned, but it is relatively small compared to the run/walk variation...
http://www.brianmac.co.uk/energyexp.htm
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web...
NO walking and running are very different in terms of efficiency. Once you are running the evidence suggests a linear relationship between pace and energy usage, which means a mile burns **about** the same.
There is some variation on pace with kcals burned, but it is relatively small compared to the run/walk variation...
http://www.brianmac.co.uk/energyexp.htm
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web...
In reply to TheDrunkenBakers:
Ok, even more than very accurate then
I have done and seen results of tests comparing HRM results against those from gym equipment. The gym equipment does not (in this case) measure heart rate but does calculations based on speed, distance, resistance, age and weight. These are the same factors and calculations most "average" figures for calories burned will use (i.e. the 100Cals/km)
Introducing heart rate into the equation (by a HRM, chest strap or hand grips) changes the results (calorie burn) significantly, by as much as 30%.
Reason?
The calculations without heart rate can't take into account an individuals efficiency or effort in terms of: oxygen delivery, cooling the body, breakdown of energy, clearance of waste by-products, etc etc.
I accept that heart rate is still a predictor of these things, but there are many studies that show that it is a reliable predictor of how hard the cardiorespiratory system is working (in that it reacts predictably to the above factors).
A simple example: Journey price calculator tells me that my car will do a trip to Keswick and back on £28 of fuel (calories). That is a pretty good estimate based on average mpg for my car and an average driving style, average conditions, medium traffic, etc. It doesn't know my true, actual mpg though. This would make it even more accurate, especially if there was a faulty sensor, I was towing, poor quality fuel, had the AC on, or that particular journey was all up hill.
If I inputted my actual mpg from the trip computer when I got home, the cost of the journey (calories) would be far more accurate. This is what sticking your heart rate into calorie calculations does.
Or simply, you have an expensive bit of technology and bought it for a reason. 25,000 Calories is a good reason to smile. Enjoy the next 25,000
> (In reply to Martin1978)
> [...]
>
> I should qualify that the Ambit is a GPS watch and so all measures are downloaded including ascent/descent so I'm assuming that this is calculated in the output.
> [...]
>
> I should qualify that the Ambit is a GPS watch and so all measures are downloaded including ascent/descent so I'm assuming that this is calculated in the output.
Ok, even more than very accurate then
I have done and seen results of tests comparing HRM results against those from gym equipment. The gym equipment does not (in this case) measure heart rate but does calculations based on speed, distance, resistance, age and weight. These are the same factors and calculations most "average" figures for calories burned will use (i.e. the 100Cals/km)
Introducing heart rate into the equation (by a HRM, chest strap or hand grips) changes the results (calorie burn) significantly, by as much as 30%.
Reason?
The calculations without heart rate can't take into account an individuals efficiency or effort in terms of: oxygen delivery, cooling the body, breakdown of energy, clearance of waste by-products, etc etc.
I accept that heart rate is still a predictor of these things, but there are many studies that show that it is a reliable predictor of how hard the cardiorespiratory system is working (in that it reacts predictably to the above factors).
A simple example: Journey price calculator tells me that my car will do a trip to Keswick and back on £28 of fuel (calories). That is a pretty good estimate based on average mpg for my car and an average driving style, average conditions, medium traffic, etc. It doesn't know my true, actual mpg though. This would make it even more accurate, especially if there was a faulty sensor, I was towing, poor quality fuel, had the AC on, or that particular journey was all up hill.
If I inputted my actual mpg from the trip computer when I got home, the cost of the journey (calories) would be far more accurate. This is what sticking your heart rate into calorie calculations does.
Or simply, you have an expensive bit of technology and bought it for a reason. 25,000 Calories is a good reason to smile. Enjoy the next 25,000
In reply to TheDrunkenBakers:
The levels recorded by HR based KCals does vary quite a bit. TO compare: My Garmin used to rate the same exercise session as about 700 kcals compared to a Polar HRM estimating about 580 on the same session.
Accuracy is increased generally when exercise is longer duration and does not vary enormously in intensity.
The best way to measure kCals from what I understand is the measurement of oxygen usage by the body, which is often done by mass spectrometry of breath live by the user.
I have had this done and for resitance strength endurace classes again this noted a particularly reduced kcal usage compared to the POlar HRM
The levels recorded by HR based KCals does vary quite a bit. TO compare: My Garmin used to rate the same exercise session as about 700 kcals compared to a Polar HRM estimating about 580 on the same session.
Accuracy is increased generally when exercise is longer duration and does not vary enormously in intensity.
The best way to measure kCals from what I understand is the measurement of oxygen usage by the body, which is often done by mass spectrometry of breath live by the user.
I have had this done and for resitance strength endurace classes again this noted a particularly reduced kcal usage compared to the POlar HRM
In reply to TheDrunkenBakers:
From what I can tell the Ambit uses a propitiatory algorithm for calories burnt. IMHO that's not good. The gold standard but impractical is to train in a lab as VO2 is important.
The best practical solution from what I can see is the algorithm from 'Firstbeat' a Finnish company. There used to be 2 Garmin 405's. A 405 and the other a 405cx. The only difference was the CX variant used the licensed Firstbeat algorithm and so cost £50? more.
I believe Firstbeat say that they are accurate to within 10%.
Checkout www.Firstbeat.fi
From what I can tell the Ambit uses a propitiatory algorithm for calories burnt. IMHO that's not good. The gold standard but impractical is to train in a lab as VO2 is important.
The best practical solution from what I can see is the algorithm from 'Firstbeat' a Finnish company. There used to be 2 Garmin 405's. A 405 and the other a 405cx. The only difference was the CX variant used the licensed Firstbeat algorithm and so cost £50? more.
I believe Firstbeat say that they are accurate to within 10%.
Checkout www.Firstbeat.fi
In reply to TheDrunkenBakers:
At least it seems more accurate than my bike computor which seems to calculate on distance & speed; if I pootle along for the same distance on the flat at the same average speed as I've busted my nuts to achieve on a hilly ride I use the same amount of calories!
I paid £2.50 extra for this and "knowing" what my carbon offset is
At least it seems more accurate than my bike computor which seems to calculate on distance & speed; if I pootle along for the same distance on the flat at the same average speed as I've busted my nuts to achieve on a hilly ride I use the same amount of calories!
I paid £2.50 extra for this and "knowing" what my carbon offset is
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