Heart Rate Dilemma

Try this...

http://www.braydenwm.com/calburn.htm

It factors in your gender, age and weight with your heart rate. It's supposed to be accurate.

Did you have to enter your gender, age and weight in the heart rate monitor? If not, it's only guessing.

You could try using this formula:

http://www.livestrong.com/article/73315-calculate-calories-burned-based-heart/

So is there is a difference in calories burnt between a

265 pound man exercising for 45 mins at a heart rate of 165
125 pound woman exercising for 45 mins at a heart rate of 165
450 pound man exercising for 45 mins at a heart rate of 165

Have all these people burnt the same calories because they have exercised for the same amount of time with the same heart rate?

It's not just a question of heart rate and time. It's a question of how much energy it takes to move mass. Think of it like this, if the 125lb woman represented a five pound dumbell when you lift it it's not super heavy so it take less energy to move. The 265 pound man represents a 25 pound dumbell it takes more energy/effort to move that and the 450 pound man represents a 50 pound dumbell which is even harder to move. If you do the same number of reps with each you use more energy to move the larger dumbells. I tend to beleive that MFP is on the high side, but not so much that it would derail you using their numbers. Good luck and good job on the workout.

So is there is a difference in calories burnt between a

265 pound man exercising for 45 mins at a heart rate of 165
125 pound woman exercising for 45 mins at a heart rate of 165
450 pound man exercising for 45 mins at a heart rate of 165

Have all these people burnt the same calories because they have exercised for the same amount of time with the same heart rate?

For determining workout intensity (and, from that, calorie expenditure) heart rate is a relative number, not an absolute number. The actual number itself is irrelevant--what is important is the "percentage of maximum" that heart rate represents. Saying "exercise heart rate is 165" is meaningless; what is meaningful is if that 165 represents 40%, 50%, 60%, 70%, etc, of maximum.

For more detail: http://www.myfitnesspal.com/blog/Azdak/view/calories-burned-during-exercise-it-s-the-intensity-not-the-heart-rate-that-counts-26524

OK...so for my question, that makes more sense. Nike+ does not calculate in heart rate at all, so it is just calculating based on distance, time, weight, sex and age. What I found last night was that the workout I had been doing was WAY intense. I spent 25 of 35 minutes outside of my zone....most if it above the ceiling #. That tells me a few things. I need to scale my workouts back and slow down a bit - hard for me because I'm super competitive and slow feels....wrong....somehow - and that I've been underestimating up until now.

In the meantime, I don't want to overestimate caloric burn because I don't want to eat back too many calories. On the flip side, I also don't want to push into starvation mode by underestimating. I'm thinking about averaging the two numbers and using that. Thoughts?

Kathy

For an established, simpler activity such as running, speed is all you need to estimate work intensity and speed and weight are all you need to estimate calories. Gender, age, and heart rate are irrelevant--those factors are needed for HRM algorithms because HRMs cannot measure oxygen uptake nor can they measure calories.

Running is a basic aerobic activity that has been well-researched and the equations to estimate oxygen uptake (and thus, calories) are well-established. Research I have seen suggest that these equations will start to overestimate calories as speeds start to go above 6 mph. And, they do not take terrain (hills) and wind into account (not that wind makes a huge difference). So calculations such as Nike+ are probably going to overestimate running calories by about 10%-15%. HRMs are no more accurate and usually a little less accurate (for running).

Again, unless you know your actual maximum heart rate, you cannot say that a workout is "too intense". A balanced cardio program should include endurance workouts, medium tempo workouts, and high-intensity interval workouts. But you need to compare your HR numbers with your breathing. If you can speak in full sentences without a little effort but not a struggle, then you are working at a low to moderate pace, regardless of the heart rate.