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TOPIC: Heart rate monitor accuracy

 
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December 27, 2010 4:26 AM
Hello, I was just wondering if anyone has come across statistics for heart rate monitors. I bought a Polar F4 with a T31 transmitter, and tried to wear it for 24 hours to see how many calories I am burning during normal activities with no workout. I took it off after 21hours and 14 minutes, and it said I burned 2561 calories.

Now, this is WAY off from the number I get when I run the RMR numbers (around 1300) using the calculator with my stats. So am I understanding this wrong? What should I base my calorie intake as? So frustrated, lol
December 27, 2010 4:41 AM
Check this artical out. Wearing your Heart Rate monitor all day will give you an idea. I would go by your BMR and stick to that number and as you loose that number may change. Because when you loose weight your body will not require as many calories


Basal Metabolic Rate (BMR) Calculator
By Dennis Thompson Jr.
Medically reviewed by Cynthia Haines, MDYou burn most of your daily calories with little to no conscious effort. Whether you're talking on the phone, working at a keyboard, or just watching television, your body is burning calories to keep your heart pumping, your lungs expanding and contracting, and your organs functioning. The calories used to maintain these basic bodily functions add up to your basal metabolic rate, or BMR. Basal essentially means base — think of it as the number of calories that are just enough to cover all your body’s bases.

"These are what I call your couch-potato calories," says dietitian Sari Greaves, RD, CDN, of Step Ahead Weight Loss Center in Bedminster, N.J,. and spokesperson for the American Dietetic Association. "It amounts to 60 to 75 percent of the total calories you use daily, and there's no physical activity required for this."

In other words, this is what you burn without lifting a finger. That’s why BMR is also is called the resting metabolic rate, or RMR, by some.

Knowing your BMR can help you create a more effective strategy for weight loss, allowing you to better keep your calorie count on track and better understand the effect exercise will have on your waistline.

Calculating Your BMR


The easiest way to measure your BMR is to use an online calculator, like the one at My Calorie Counter. This calculator factors in your height, weight, gender, and age, and activity level, then assesses how many calories you need to eat daily just to maintain your current weight.
You can do the math yourself, using the appropriate equation:

• If you’re a man, your BMR is equal to: 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years). For example, if you’re 170 pounds, 5’11”, and 43, your BMR is 66 + (6.23 x 170) + (12.7 x 71) – (6.8 x 43) = 1734.4 calories.
• If you’re a woman, your BMR is equal to: 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years). For example, if you’re 130 pounds, 5’3”, and 36, your BMR is 665 + (4.35 x 130) + (4.7 x 63) – (4.7 x 36) = 1357.4 calories.
Next figure out your total daily calorie requirement by multiplying your BMR by your level of activity:
• If you rarely exercise, multiply your BMR by 1.2.
• If you exercise on 1 to 3 days per week, doing light activity, multiply your BMR by 1.375.
• If you exercise on 3 to 5 days per week, doing moderate activity, multiply your BMR by 1.55.
• If you exercise 6 to 7 days per week, doing vigorous activity, multiply your BMR by 1.725.
• If you exercise every day and have a physical job or if you often exercise twice a day, multiply your BMR by 1.9.

If the man in the example exercises 3 days a week, doing moderate activity, his daily caloric requirement is 1734.4 x 1.55, or 2688.3 calories.

If the woman in the example exercises 6 days a week, her daily caloric requirement is 1357.4 x 1.725, or 2342.5 calories.

This calculation gives you the number of calories you burn in one day at your current level of activity; in other words, this is the number of calories it takes to stay at the weight you are if you don’t change anything.

Applying Your BMR Calculation to Weight Loss


Once you know your BMR and the number of calories you burn for your activity level, you can improve your weight-loss efforts by setting a lower daily calorie-intake limit and crafting a plan for increasing your physical activity:

Set your daily calorie limit. To lose weight, you need to reduce your caloric intake below your total daily calorie requirement indicated by your BMR + activity level. Putting yourself in a 500-calorie deficit every day should result in the loss of one pound per week (since there are 3,500 calories in a pound), Greaves says.

Adjust your exercise output. Our BMR calculator asks you for your level of physical activity for a very good reason. You can influence your BMR through exercise, spurring your body to burn more calories even after you’ve finished and are just lounging about.

• Aerobic exercise provides a temporary boost to your BMR, an effect sometimes referred to as after-burn or excess post-exercise oxygen consumption, says Noelle Lusardi, a certified personal fitness trainer who also works at the Step Ahead Weight Loss Center in Bedminster, N.J. Your BMR will return back to its normal level anywhere between 15 minutes and 48 hours.

• Strength training provides a more-lasting boost to BMR by altering your body's composition. Muscle at rest burns more calories than fat at rest. That's why men enjoy a naturally higher BMR than women, as they tend to have more muscle mass, Greaves explains.

• If you cut calories and increase your BMR by exercising, you’ll see results even faster. Increase the amount of calories you burn by 250 each day, and you’ll lose a half-pound more on top of the calorie cuts made in your diet. You could exercise longer or you could increase the intensity of your workouts to burn more calories — either way will increase the calorie deficit.

The advantage of knowing your BMR is that you can learn the number of calories you need to consume and expend to meet your personal goal for weight loss.
December 27, 2010 4:43 AM
Also remember you have to take your BMR and multiple it by your activity level.
December 27, 2010 4:48 AM
QUOTE:

Hello, I was just wondering if anyone has come across statistics for heart rate monitors. I bought a Polar F4 with a T31 transmitter, and tried to wear it for 24 hours to see how many calories I am burning during normal activities with no workout. I took it off after 21hours and 14 minutes, and it said I burned 2561 calories.

Now, this is WAY off from the number I get when I run the RMR numbers (around 1300) using the calculator with my stats. So am I understanding this wrong? What should I base my calorie intake as? So frustrated, lol


I have the same heart rate monitor. Make sure you have your height, weight, etc. set right in the settings. I set mine for a higher weight when I first started and didn't adjust. It definitely makes a difference.

I found that when I wore it during the day at work, I was burning about 100 calories per hour (i.e. desk jockey). I have not worn mine while sleeping.

Also, when setting your calories, I agree with the previous post. Calculate your BMR and use that as a target. Use the heart rate monitor when exercising (i.e. cardio) to calculate and keep track of the calories burned. I also use the Polar site to upload my information and keep track of it there. Later on I can go back and see how many calories I burned per day, week, month, etc.
  2436356
December 27, 2010 5:02 AM
Your RMR is what you need if you didn't get out of bed all day. You did normal activities, showering, washing clothes, some light walking to and fro.

Also RMR's are calculated based on numbers not on your metabolic rate. You also may have a faster heart beat and the HRM goes with that.

I saw a study on TV once where they said HR monitors overall overestimate your calorie burn, but the ones with chest straps are the most accurate, although they still over estimate. They were comparing, Cardio Machines, HRM's with no strap, HRM's with a strap, and Medical monitoring or calorie burn.
December 27, 2010 5:12 AM
You cannot use an HRM to estimate calories burned at rest. I know it's one of the first things that people try when they get a new one--but the number is not real.

HRMs do not measure calories. They estimate calories burned based on mathematical formulas. These formulas are derived from the relationship between heart rate and oxygen uptake during steady state aerobic exercise. What accuracy they have only holds true under those conditions.

If you are doing recreational or work activity that is sustained and that exceeds 40% of your VO2max, then HRMs are more accurate at estimating the calories (some of that accuracy is lost when the activity involves extensive upper body work). But for anything else, the number you see is based on false readings.

I have found that the BMR calcluator on MFP is quite good. It should be sufficient for the vast majority of MFP users.

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