Verifying Daily Calorie Burn with HRM

As many others on this cite, I've been confused by the calorie burn meter, constantly wondering if it's accurate. After all, so much goes into the number that we can hardly expect a few questions to lead us to a number that is 100% spot on, right?

So last week, I decided to wear my Polar HRM for three hours while I rested/napped. I've been sick, so I'm low on energy anyway. In that 3 hour rest period (laying on the bed, intermittently sleeping/reading with one trip to the restroom), I burned 350 calories. Is it then reasonable to multiply that number by 8 to figure out what I burn in a 24 hour period of rest (sedentary activity level)? If that is really the case, I burn 2800 calories on a sedentary day. That is WAY more than Calorie Count suggests I burn, which means I ought to be eating far more calories than I am.

Thoughts?

Polar HRMs are not calibrated to measure calories burned when inactive.

I'm not sure that's true. My physical trainer told me that it was actually a good way to figure out my burn all day. As long as the signal is reading, it registers my heart rate. Knowing how many calories you burn in an hour without working out is actually helpful in determining if you are working out to a sufficient level. If I burn 100 calories an hour just sitting around, then I know burning 400 calories in 2 hours isn't all that significant, because it's only 100 calories an hour more than I'd normally burn.

My HRM indicates what percentage of my max HR I'm at. So while I'm at rest, my HR falls between 38 and 55% of the max. When I'm working out, I should aim for between 65% and 90%. There's no reason to believe the monitor doesn't read the HR when it's low.

I didn't say that it can't monitor your heart rate when it is low. I said that it isn't calibrated to calculate calories burned when you heart rate is low.

As a heart rate monitor, you can use it all day long. As a calorie counter, it will only be accurate while your heart rate is elevated.

This is why they now have the BodyBugg and GoWearFit, which can used to measure calorie burn even when inactive, but of course are more expensive than a typical Polar HRM.

How many calories are you currently eating? Does your current rate of weightloss and calories consumption suggest that the 2800 calorie burn is accurate?

Floggingsully: I eat between 1500-2000 calories a day. I haven't been losing weight, and I've been counting for over a year. That's why I'm investigating some of the aspects of fitness and weight loss more thoroughly... I"m tired of people saying it's a matter of basic math when, apparently for me, it itsn't.

How frustrating! How much does CC say you burn (and have you looked at other calculators, like www.phord.com/cc)?

Original Post by counselork:

Floggingsully: I eat between 1500-2000 calories a day. I haven't been losing weight, and I've been counting for over a year.

 Then I think it's safe to say that you're not burning 2800 calories when sedentary.  If you're really eating 1500-2000 and your weight is staying the same, then your burning about 1500-2000.

The math is basic, figuring out which numbers to plug into the equation is not.

Agreed, you cannot use an HRM to figure out your resting calorie burn. It's only good when your heart rate is elevated. Good luck to you!

Wondering the same thing, I have tried wearing my HRM all day... I have recently purchased a Bodybugg (highly recommended, BTW).

CC told me I burn 1500 cals/day at "sedentary" and would estimate my workouts at ~300/day for a total of ~1800/day

My HRM told me I burn ~2400 cals/day

The Bodybugg tells me I burn an average of ~2200/day

Calorie Count told me to eat 1200 cals/day as a baseline, and I would "add back my exercise calories" to my daily consumption.

My thoughts: Invest in the BB if you're serious - I was clearly not eating enough.

Don't know if this makes a difference, but I'm not terribly overweight. My BMR is 1500/day, and I'm aiming to go from 150 to 136 pounds. I work out regularly and lift weights, and some of my weight stagnation has to do with the shift from body fat to increased muscle mass. My trainer estimated a burn of 2400 on days I work out, 2200 on days I don't. Even if 2800 is high, I should still be losing weight at 1500 a day. The fact that i'm not leads me to believe the estimate is wrong. I don't have any extreme metabolic issues - my thyroid is low-normal, estrogen is within the normal range, etc. And the weight gain was a sudden gain attributed to birth control pills, which I am no longer taking (as of 17 months ago).