HRMs, how calories are burned, "the zone", confusion

joytron

I purchased a Polar HRM recently to determine how many calories I'm *really* burning, as there's so many different numbers from different sources.

When I did a fast walk for 50 minutes, it said I burned roughly 230 calories. My average heart rate was 108, and I was in the zone (I take this to mean 60-80 % of my max?) for a grand total of 13 seconds. :laugh: Anyway, the calorie burn was roughly the same for what MFP had calculated, so, cool.

The next day, my workout was a 50-minute kickboxing DVD. I was VERY curious with this one, because in the past MFP had estimated a 450-calorie burn for me, and the participants on the DVD (who all wear HRMs) were raving at the end about how they'd all burned like 600-800 calories. So obviously I was mad-curious, and imagine my surprise when my HRM delivered the verdict: 352 calories burned! I was super-disappointed, but figured I probably wasn't working "hard enough". So I checked the other stats, and it said my average heart rate was 130 and that I'd been in the zone for 40 minutes.

So, my questions:
- Do I just need to be pushing myself WAY harder during the kickboxing DVD? Aiming to be in the zone for all 50 minutes? (For the record, it feels like I *am* pushing myself very hard, already.)
- If not, and 350 is an acceptable burn for 50 minutes of kickboxing, do you know of any other workouts with a higher calorie burn per minute? Or is it all just heart rate (ugh, I'm cringing at how dumb this sounds)?
- Oh, some of you may recommend weights, and I intend to get into those, but it's not feasible for the next month or two so I have to stick to cardio for now.
- Finally: Do I need to subtract whatever calories I'd be burning just by breathing from what the HRM says before logging it on MFP?

Thanks a heap in advance, I know there's some geniuses on here! Any response appreciated, and/or links to relevant articles.

Oh, my deets: female, 31 years old, 5.2, 140 pounds.

jacksonpt

A few things...

1) "the zone" is a crock. Exercise burns cals. What those cals are depends on a lot of things.
2) don't compare your burns to other people's - it'll just drive you crazy
3) All these numbers (your HRM, MPF, etc) are all just estimate. Pick one that you like and use it. There is no exact way to measure.
4) Push yourself as hard as you can. If you are doing that, everythign else will fall into place.
5) Burns are going to vary person to person and exercise to exercise. What may be a big burn for me may not be for someone else. Do what YOU like to do and that gives YOU a good workout, not what other people say you should do.
6) Some people do subtract out the cals, some don't. IMO, it's not necessary. Virtually everything we do in all this is an estimate. We estimate how many cals we burn. We estimate how much we eat. We estimate our BRM. Etc etc etc. Subtracting out 30 cals from your workout to be more exact is, IMO, needless obsession. Can it hurt? No. Is it necessary? Not IMO.

Cyclink

^^^^^^ What he said.

joytron

Thank you very much! That is excellent advice; it puts a lot of things in perspective for me. :-)