polar HR calorie counter

[mr Mag00]

Hey does anybody have any evidence that these calorie measurements within a polar HR are any good or miles, no pun intended, from the truth. My HR asks for age, height, weight and i have sat through the fitness test so surely they must be relatively accurate? ur comments as always requested (well i will get them anyways )


answers on the back of a stuck down envelope or postcard to:

 

[jimboalee]

I don't personally think they are much good.

For example, if you stood out in today's wind in just your underpants, you'd shiver yer nuts off, burning more calories than riding a bike at 20 mph.
Your heartrate wouldn't rise much, but the little muscles in you hair folicles would be working overtime, in sympathy with the involuntary spasms of shivering.

In this case, HR bears NO relationship to calories burned.

That's my view.

 

[Eat MY Dust]

I've got a Polar AXN300 and I find that the reading I get for calories is pretty spot on when I compare it to other methods/formulas.

I've no idea why you'd want to stand outside in your underpants in today's wind to measure the effects of muscle spasms, I'll leave that to Jimboalee!!!!

 

[mr Mag00]

I don't personally think they are much good.

For example, if you stood out in today's wind in just your underpants, you'd shiver yer nuts off, burning more calories than riding a bike at 20 mph.
Your heartrate wouldn't rise much, but the little muscles in you hair folicles would be working overtime, in sympathy with the involuntary spasms of shivering.

In this case, HR bears NO relationship to calories burned.

That's my view.

based on what??
so that is why you see pro riders built like brick shoot houses? what utter claptrap!!
that was why i asked this question on a cycling forum and not a fetish forum about underpants
aerobic and anaerobic threshold mean nothing to you i take it.

is there anybody out there who would like to discus this properly without standing outside in underspants *rollseyes*

 

[Steve Austin]

They 'assume' an average for your workouts, so its always going to be a rough estimate. but you knew that

I ride MTB and road, and My heart rate on the road on average is generally lower, but i burn more calories according to my Garmin. MTBing is harder (physical) work i find, but i use less calories.

The garmin has no idea what activity i'm doing so as far as i'm concerned the road or the MTB activity means little to the amount of calories to my garmin, and its just guessing how many calories i've burned.

Not to say.its not a good measure for me to estimate how hard i've worked

 

[Fab Foodie]

I don't personally think they are much good.

For example, if you stood out in today's wind in just your underpants, you'd shiver yer nuts off, burning more calories than riding a bike at 20 mph.
Your heartrate wouldn't rise much, but the little muscles in you hair folicles would be working overtime, in sympathy with the involuntary spasms of shivering.

In this case, HR bears NO relationship to calories burned.

That's my view.

IMO they're a reasonable guide.
In answer to the above, HRM's measure heart rate bpm. The heart pumps blood carrying oxygen around the body, under most circumstances Oxygen is required to burn fuel (OK, there are short anaerobic periods, however they come with an oxygen debt which must be repaid in an innefecient way). So the more work your body does, the more fuel it meeds, the more oxygen required to burn the fuel, the more the heart has to work to supply the fuel.
The stoichiometry of the chemistry and physiology is pretty well understood and so a mathematical correlation can be made between HR and Calories of fuel being burned.

Be in no doubt than when shivering in the cold your heart rate rises, it has to to provide the extra fuel to generate the muscle spasm, the movement of haire follicles AND efficiently burn fat to generate heat in Brown Adipose Tissue. Riding a bike at 20mph will probably use more calories per hour than violent shivering.

 

[fossyant]

Jim's off again..stats...stats...stats......

They are very rough, but I reccon if you ride very hard you'll burn 800-1000 cals an hour......

 

[LondonCommuter]

All I can say is that when I changed from Polar to Suunto I got very different (lower) readings for my calorie count. I have no idea which is more accurate, though the Suunto claims to be more sophisticated

 

[Ravenz]

The readings from HRMs for calorie burn are usually not far off the mark.. you can use METS (metabolic equivalents) to do your own calculations for how many calories you are burning off for any particular form of exercise from walking .. gardening thru to time trialling.. but if you are not into 'weightloss' as a goal, then calorie burn is not very exciting aprt from it being a reminder to EAT during longer bouts of cycling - something that you only do once never to repeat again as your legs jellify and the spirit sinks...

 

[Fiona N]

I'm fairly sure a Polar HRM calorie counter will be based on their exertion estimate method which uses the time in each exercise zone (you may have set these or otherwise it will make assumptions based on percentages of HRmax) and multiplies this by an exertion factor which is non-linear scale - so for example, working at 80% HRmax for 10 minutes uses much more than 2x calories of 10mins at 40% HRmax. The Polar download software allows you to tweak these exertion factors as they vary somewhat depending on the exercise and how fit you are. The calorie estimate is obviously likely to be closer to reality if you have programmed in as much HR data as possible. Comparing the results from my Polar HRM with data from actual VO2 max testing and so on, it's not bad - within about +/- 10% for short tests.

 

[Bodhbh]

I don't personally think they are much good.

For example, if you stood out in today's wind in just your underpants, you'd shiver yer nuts off, burning more calories than riding a bike at 20 mph.

Reminds me of a friend who reckoned you could loose weight by drinking pints of ice-cold water and causing you're body to burn calories heating up. If that were true, why not loose weight drinking ice-cold guinness...

Forget the maths now, 37kcal is the energy required to heat up a litre of water 37degrees? Not gonna get you slim in a hurry!

 

[jimboalee]

Yes, one would think that cycling at 20 mph would use the 'lion's share' of calories burned, but if you do the kW maths, you'll find that tractive force is only responsible for about 30% of the total calorific expenditure.
The rest of it, like a car engine, goes out as heat.
When you read in text books that cycling at 20 mph consumes 12 kCals/min, the energy that is burned pushing the bike forwad is close to 4 kCals/min. The text books et al take the assumption the cyclist is wearing shorts, short sleeve jersey and cycling in 16 deg C air temperature.

If you wear a HRM in a gymnasium environment, the 'cookbook' lookup tables it contains will probably be close to the truth, but if you go out in the cold breeze in your shorts and short sleeves, the HRM won't factor in the effects of windchill.

Anyway, kCals/min are relative to Watts, which are relative to Joules/second, so any activity can be calculated by measuring how many kgs are being lifted so many metres against gravity in so many seconds.

 

[Fab Foodie]

Yes, one would think that cycling at 20 mph would use the 'lion's share' of calories burned, but if you do the kW maths, you'll find that tractive force is only responsible for about 30% of the total calorific expenditure.
The rest of it, like a car engine, goes out as heat.
When you read in text books that cycling at 20 mph consumes 12 kCals/min, the energy that is burned pushing the bike forwad is close to 4 kCals/min. The text books et al take the assumption the cyclist is wearing shorts, short sleeve jersey and cycling in 16 deg C air temperature.

If you wear a HRM in a gymnasium environment, the 'cookbook' lookup tables it contains will probably be close to the truth, but if you go out in the cold breeze in your shorts and short sleeves, the HRM won't factor in the effects of windchill.

Anyway, kCals/min are relative to Watts, which are relative to Joules/second, so any activity can be calculated by measuring how many kgs are being lifted so many metres against gravity in so many seconds.

Do you work hard making-up this stuff or does it come naturally?

At 20mph on a bike most work done is overcoming wind resistance.
HRM will factor-in windchill if you're maintaining body temp as explained, if you're using energy, you need Oxygen, more energy use, more oxygen use = more heart rate to supply the Oxygen. Simple. The HRM opnly measures total energy consumption, not just energy use due to cycling, so on a cold day cycling, the calories burned will be those to pedal and those to keep warm assuming the heat of the excercise does not provide sufficient heat.

 

[jimboalee]

Ok, you tell me. How many kCals/min for tractive motion at 20 mph?


And some more questions.

How many calories? How much CHO will you eat?

Q1/ 10 mins to the shop, 10 mins back.

Q2/ 10 miles to work, 10 miles home.

Q3/ 100 km Audax.

Q4/ 200 km Audax.


Assuming 8 kCals/min, 2.5 of which are Tractive.

 

[jimboalee]

I'll give you a clue.

FL = 0.5 x Q x Cd x A x v^2