Stupid question?

IamOnMywayNow

While on the treadmill I was lightly jogging (4.2mph at a 1.5 incline) to warm up (5 minutes) and noticed that my heart rate was in the 157-162 range. I did my run and when my lungs could not take it anymore I decided to lower my speed to 3.0mph and upped the incline to 8 for the last 10 minutes. I again noticed that my heart rate was in the 157-162ish range. Now my question is, no matter how fast I am going, my heart rate is what matters as far as burning calories/fat, right?

aakaakaak

Not to get in Sara and SS's way, but were you, by chance, using the built-in HRM on the machine, or your own chest strap?

Edit: Hopefully this WebMD link can help with some answers before the smart people weigh in:
http://www.webmd.com/fitness-exercise/features/the-truth-about-heart-rate-and-exercise
(I haven't vetted everything in the article, so whatever trustworthiness you put on WebMD is what you get.)

heybales

Not calories totally, but what ratio carbs to fat yes within limits.

Your HR tied to calorie burn is a loose association that is the best you can get without more expensive equipment.

Notice that phrase - that is not the same as saying it IS the best you can get. It's not.

You likely experience cardiac drift.

Run the exact same pace / incline for 60 min.

You'll start out high as you aren't warmed up and blood needs to get flowing and oxygen to the right spots.
Initial big drop of maybe 10-15 bpm in 5-10 min.
From there on out, if you graph it, the HR slowly starts to rise until the end.

Now, did the energy required to push your body free from the grasp of gravity change the longer you did it?

Not at all. Only if you started running really inefficiently the longer you went (which could happen slightly) - but usually not to the change you'll see in 60 min.

That's another reason why a decent treadmill that asks for your weight will be more accurate than a HRM for calorie burn.

What if you just had a big coffee and caffeine has your heart racing before you even get on the treadmill, and of course it's elevated HR during the run. More calories burned? No.

How about gym AC wasn't working and you heated up massively, and HR was up to pump more blood for cooling effect? No, ever so slightly as faster HR is more energy for heart, but not rest of the body.

How about you are tired from previous day's lifting and in fact run slower, but HR is higher than normal? No, just stress related.

http://www.myfitnesspal.com/topics/show/773451-is-my-hrm-giving-me-incorrect-calorie-burn

And to see how decent yours is estimating (not measuring) calorie burn.

http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is

Also noticed comment about using HRM on machine - that is merely display, it's never used in calculations because the reading may be gone or sporadic, the receivers on that can be slower, and have interference, so they never base calorie burn on them.

And yes to higher HR means bigger ratio of carbs to fat, at anaerobic threshold, total carbs. Fat requires oxygen to burn, anaerobic though - without oxygen fuel burning. At lowest exercise level, probably 70% fat burned.
But much more calories at higher level, usually about the same quantity of fat, even though % is lower.

Sarauk2sf

Leaving this one to heybales...coz running and HRMs are not exactly our forte!

IamOnMywayNow

Not calories totally, but what ratio carbs to fat yes within limits.

Your HR tied to calorie burn is a loose association that is the best you can get without more expensive equipment.

Notice that phrase - that is not the same as saying it IS the best you can get. It's not.

You likely experience cardiac drift.

Run the exact same pace / incline for 60 min.

You'll start out high as you aren't warmed up and blood needs to get flowing and oxygen to the right spots.
Initial big drop of maybe 10-15 bpm in 5-10 min.
From there on out, if you graph it, the HR slowly starts to rise until the end.

Now, did the energy required to push your body free from the grasp of gravity change the longer you did it?

Not at all. Only if you started running really inefficiently the longer you went (which could happen slightly) - but usually not to the change you'll see in 60 min.

That's another reason why a decent treadmill that asks for your weight will be more accurate than a HRM for calorie burn.

What if you just had a big coffee and caffeine has your heart racing before you even get on the treadmill, and of course it's elevated HR during the run. More calories burned? No.

How about gym AC wasn't working and you heated up massively, and HR was up to pump more blood for cooling effect? No, ever so slightly as faster HR is more energy for heart, but not rest of the body.

How about you are tired from previous day's lifting and in fact run slower, but HR is higher than normal? No, just stress related.

http://www.myfitnesspal.com/topics/show/773451-is-my-hrm-giving-me-incorrect-calorie-burn

And to see how decent yours is estimating (not measuring) calorie burn.

http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is

Also noticed comment about using HRM on machine - that is merely display, it's never used in calculations because the reading may be gone or sporadic, the receivers on that can be slower, and have interference, so they never base calorie burn on them.

And yes to higher HR means bigger ratio of carbs to fat, at anaerobic threshold, total carbs. Fat requires oxygen to burn, anaerobic though - without oxygen fuel burning. At lowest exercise level, probably 70% fat burned.
But much more calories at higher level, usually about the same quantity of fat, even though % is lower.

Wow! Thanks for the info:)

alanlmarshall

If burning fat is the only goal, then running at a certain heart rate is an inefficient way to reach that goal. The differences aren't that meaningful. HIIT and caloric deficit will get you there much faster and more simply. I wouldn't worry about heart rates and target zones and all that. If you are training for a race or to improve performance that is different.

Sarauk2sf

If burning fat is the only goal, then running at a certain heart rate is an inefficient way to reach that goal. The differences aren't that meaningful. HIIT and caloric deficit will get you there much faster and more simply. I wouldn't worry about heart rates and target zones and all that. If you are training for a race or to improve performance that is different.

I agree with this sentiment.