Questions about cals burned per minute of activity and BMI

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2008-01-24 7:46 AM

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Forestville,NY
Subject: Questions about cals burned per minute of activity and BMI

I'm currently trying to take my nutrition to the next leval.  I'm affraid its hurting my performance.  I feel tired and mentally slow even after 8-9 hours sleep and I drink lots of water.  I think I may not be getting in enough cals a day.  I'm very aware of what I eat and try aware from processed and refined foods. 

My question is with my HRM it will say my calorie's consumed for a particular activaty will be one number while the formula in the book "Sports Nutrition for Endurance Athletes" will be very different.  I'm 160 lbs and run 10' miles on my long runs (90'+).  According to the book my calorie expendature will be 1048 calorie's for a 90' run.  My HRM gives me in the area of 1400.  I'm using a Polar F11.  Also the book says that biking on a flat road with no wind burns more calories than running.  My HRM tells me the opposite.  Which way do I go? 

Also whats the best and cheapest method of getting ones BMI.  At this point I can't afford some crazy test.

 

Thanx I'm sure I'll have plenty of other questions soon enough.

 

Justin   

2008-01-24 8:44 AM
in reply to: #1173448

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Lansdale, PA.
Subject: RE: Questions about cals burned per minute of activity and BMI
There are lots of reasons why the numbers are different. More than likely they are using different formulas but you also must factor in the actual effort that your HRM is recording versus the book which is using some type of average.

As for BMI, there are calculators on line that will estimate it for you. i have a Tanita Ironman Body Composition Scale which calculates lots of things including BMI. Really never paid too much attention as i am sure I am right around where i need to be given my activity level. See if you can find someone nearby with one of those scales. They aren't cheap, as scales go but it calculates body fat, visceral fat, BMI, Weight, body water, muscle weight, bone weight so for about $100 it really gives you a lot of info. The link below has my scale. I have the BC-554

http://www.tanita.com/IronManScales.shtml
2008-01-24 8:59 AM
in reply to: #1173448

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Westlake, OH
Subject: RE: Questions about cals burned per minute of activity and BMI
PDA - 2008-01-24 8:46 AM

I'm currently trying to take my nutrition to the next leval.  I'm affraid its hurting my performance.  I feel tired and mentally slow even after 8-9 hours sleep and I drink lots of water.  I think I may not be getting in enough cals a day.  I'm very aware of what I eat and try aware from processed and refined foods. 

My question is with my HRM it will say my calorie's consumed for a particular activaty will be one number while the formula in the book "Sports Nutrition for Endurance Athletes" will be very different.  I'm 160 lbs and run 10' miles on my long runs (90'+).  According to the book my calorie expendature will be 1048 calorie's for a 90' run.  My HRM gives me in the area of 1400.  I'm using a Polar F11.  Also the book says that biking on a flat road with no wind burns more calories than running.  My HRM tells me the opposite.  Which way do I go? 

Also whats the best and cheapest method of getting ones BMI.  At this point I can't afford some crazy test.

 

Thanx I'm sure I'll have plenty of other questions soon enough.

 

Justin   



I don't know if this will answer your question directly, but here are some random thoughts.

Your polor and that book are using estimates based of certain factors. I'm not surprised they are different.

Calories burned are, to the greatest extent, a function of how much you weigh and how far you ran. How fast you run, for the most part, only contributes to how far you run in a give time. Example = two people weighs the same. A runs 8'miles while B runs 10'miles. A runs 5 miles in 40 mins. B runs 5 miles in 50 mins. Each burn nearly identical cals.

So in your example, a 90 min at 10'/mile would be 9 miles. Here are the cals from three on-line calcs for your weight and a 9 mile run.

1. 940.32
www.clevelandclinic.org/health/interactive/calories.asp
2. 940.32
http://www.coolmath.com/calculators/calories.htm
3. 1090
http://www.healthatoz.com/healthatoz/Atoz/tl/misc/caloriesburned.js...

I was surprised that the first two came out the same. They must just use the same formula. While the 3rd uses another formula. Since they are all around the same, I would use ~ 100 cals / mile to figure your cals burned.

How does your polor figure your cals? Are you imputing time, weight, and distance into?

BMI? the cheapest way would be to see the following - http://www.cdc.gov/nccdphp/dnpa/bmi/adult_BMI/english_bmi_calculato...

I don't take much stock in BMI however. That cal shows I'm overweight. Body Fat percentage is a much better indicator of fitness. The body fat test I had on Monday showed that I had a BF% of 15%. Very acceptable for an adult male of 41 and consider in the "fitness" category by the american council on fitness.

I had my BF test done at my rec center for free. It was a simple three area pinch test. They had a little expo sonsored by a local hospital that was putting it on. I would think that you could have this test done pretty cheaply at a local fitness club or clinic. Google it.
2008-01-24 7:15 PM
in reply to: #1173448

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Subject: RE: Questions about cals burned per minute of activity and BMI

My HRM I'm assuming uses the duration, weight, and HR to come up with some number.

 

 



Edited by PDA 2008-01-24 7:42 PM
2008-01-24 8:09 PM
in reply to: #1175008

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Subject: RE: Questions about cals burned per minute of activity and BMI
PDA - 2008-01-24 8:15 PM

My HRM I'm assuming uses the duration, weight, and HR to come up with some number.

 

 



No pace? No distance? How does it know you are actually moving? Or how far? Person A could have a HR of 150 going 4.0mph while person B could be moving @ 8.0 mph with the same HR. If they both went 1 hr, person A would have gone 4 miles while B would have gone 8. Guess which one burned more cals. Seems like your polor is using a lot of assumptions.
2008-01-27 11:48 AM
in reply to: #1173448

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Subject: RE: Questions about cals burned per minute of activity and BMI

The truth is Justin neither of the methods are that accurate.  How many calories you burn per min or hour completely depends of your level of fitness.  I am a cardiologist in Tucson Arizona and also an avid triathelete. I specialize in prevention, imaging and performace and weight managment.

In my weight managment clinics I do resting metabolic rate and VO2 testing.  I can tell you that after testing many, many patients that as they progress through my program the amount of calories they burn at a given heart rate dramatically changes.

The easiest way to understand it, is that the fitter you are (from a cardiopulmonary standpoint) the more efficiently you can deliver O2 and energy to metabolizing tissue hence the faster you burn calories.

For example, you can  have 2 people both who weigh 160 lbs, the first person who has a peak VO2 of 64 might burn up 800 c/hr at a heart rate of 135.  The second person whos peak V02 is 35 might only burn up 450 c/hr at the same heart rate

Hope that helps

drsal

2008-01-29 8:04 AM
in reply to: #1173448

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Forestville,NY
Subject: RE: Questions about cals burned per minute of activity and BMI

Yes it does.  Thank you everyone for your reply.  I'll just use my RMR then adjust my calorie intake based more on how I feel not what the numbers say. 

2008-02-01 2:58 AM
in reply to: #1173448

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Zürich, Switzerland
Subject: RE: Questions about cals burned per minute of activity and BMI
Running burned calories are very simple: your total weight x km
Indipendently of the speed you go. If you use cal/min then it is more difficult. Measure the distance and you are there!
For bike, it very depend on the speed and on the road altimetry: tipically for your body I would say an average of 11cals/min for a 25-30 km/hrs training but it can be different if you do 40km/hrs training or a 20km/hrs one, and from your level of fitness.
You can not say the same cals/km you say for running.
Swimming is a little bit lower where for 3000yds/hours speed you burn around 10 to 11 cals/min
2008-02-05 11:06 PM
in reply to: #1178275

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Subject: RE: Questions about cals burned per minute of activity and BMI
drsalcardiology - 2008-01-26 6:48 PM

The truth is Justin neither of the methods are that accurate. How many calories you burn per min or hour completely depends of your level of fitness. I am a cardiologist in Tucson Arizona and also an avid triathelete. I specialize in prevention, imaging and performace and weight managment.

In my weight managment clinics I do resting metabolic rate and VO2 testing. I can tell you that after testing many, many patients that as they progress through my program the amount of calories they burn at a given heart rate dramatically changes.

The easiest way to understand it, is that the fitter you are (from a cardiopulmonary standpoint) the more efficiently you can deliver O2 and energy to metabolizing tissue hence the faster you burn calories.

For example, you can have 2 people both who weigh 160 lbs, the first person who has a peak VO2 of 64 might burn up 800 c/hr at a heart rate of 135. The second person whos peak V02 is 35 might only burn up 450 c/hr at the same heart rate

Hope that helps

drsal



Good point. So probably you are a good person to ask whether the Polar (S625X) does good job to estimate burned calories for each sport, especially running and bike after you do the VO2 test and all the other fitness tests. I see it on running well matching with the kmxweight while I do not know for cycling...
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