900 calories in aerobic kickboxing class???

beezee178
beezee178 Posts: 5
in Fitness and Exercise
Hi,

I'm quite intrigued by how people work out calorie usage during exercise classes and how accurate it all is. I do a fair bit of running and when chatting to my neighbour I had mentioned that I generally use around 550-570 calories over a 10km run. I'm currently 57kg. For a 21km run I usually come in around the 1250-1300 calories.

All of my data comes from my Garmin Forerunner 305.

My neighbour expressed surprise that my calorie burn was so low and mentioned that they had a heart rate monitor at her aerobic kickboxing class the other week and people (and not even those that seemed to be working hardest) were getting calorie burns of around 900 calories over the hour class.

This seemed crazy high to me as I've done aerobic kickboxing classes on many occasions and certainly felt NOWHERE near as knackered as I would after a 900 calorie burn from a run (equates to about a 16km run for me ... and if I go out and run 16km I'm definitely going to feel more tired than from gym class!). I've also done a lot of cycling and I know that I had to cycle hard out for over 30km to pull near 600 calories. 900 calories is a LOT of energy.

Further to this, I wore my HRM today during a Michelle Bridges Workout DVD and according to Garmin my calorie burn was only about 400 calories. This makes sense to me (I feel like I've done 400 calories - have done some exercise but nothing extreme!).

So my questions are: do I just burn really low calories? Or am I not reading my Garmin correctly? How accurate are calorie burn calculations from HRM anyway? 900 calories for a mid sized female (approx 70kg apparently) is miles away from the kinds of results that I can pull and I'm pretty fit so do put in a lot when I exercise.

Thanks, Belinda

Replies

  • meshashesha2012
    meshashesha2012 Posts: 8,329 Member
    is your neighbor the same height, weight, gender, age and fitness level as you? if those things are different then of course your clorie burn will be different.

    the fitness level thing can also account for lot, especially with other things being different. for instance i'm about 60 pounds overweight, but i've consistently worked out for decades so i'm in fairly good shape. compared to a friend of mine who's similar height weight age but who isnt as much of a jock, i'm in awesome shape. so we can take the same kickboxing class, my average heart rate is 120s and her's is 180's so she'd going to burn more calories than me.

    the las time i was able to burn 900 calories was a 85 minute workout where i worked out with weights, did sprints and kept my heart rate at an average of 170's the entire time. i was pretty much dead by the end and it took me 20 minutes to walk 3 blocks home :laugh:
  • beezee178
    beezee178 Posts: 5
    Lol ... yup that's me too! 900 calories for me is a 16km run sitting around the 170 bpm average and there's no way I'm going to finish that in an hour either! I do at least an hour of exercise every day but after a 900 calorie session I would definitely know I'd been given a good going over and I don't think I'd want to do this as a daily workout before heading off to my day job :)

    The general differences from person to person might have something to do with it. I run a lot of distance races so my heart rate sits quite low these days. I'm also quite small so I do understand that a bigger person would burn more but I am just gobsmacked at the 900 calorie per hour concept. From what I understood the ladies who were saying that they were getting the 900 calorie results were approx 65-70kg - so really only 10-15kg over my own weight. I have no idea what kind of HRM they were using to get the results.

    Even so I'm having difficulty getting my head around it ... I can work out HARD for an hour, dripping with sweat and am apparently only getting half the calorie burn! I can only imagine burning 900 calories in my daily hour workout ... my mind boggles with how much I could eat with that kind of daily deficit :D

    I think I will go along to this particular kickboxing class and wear my HRM just to compare my own stats but I can't see me getting anything like a 900 result!
  • manda1978
    manda1978 Posts: 525 Member
    Sounds like a simple case of you're fit and she's not lol.

    I did 2hrs of training yesterday morning being 1hr of boxing and 1hr of bootcamp, in total I burnt around 1050.
  • beezee178
    beezee178 Posts: 5
    That makes much more sense to me ... that's 500 odd an hour which is about what I expect to burn at classes/running/cycling (give or take a hundred or so depending on type of exercise).

    Bootcamp is one I haven't tried yet ... I see them when I run sometimes in the mornings though and it does look like fun!! :)
  • Confuzzled4ever
    Confuzzled4ever Posts: 2,860 Member
    I have no idea what i burn.. I log it here just to have a record of what I do and to keep myself accountable to myself. I don't eat back exercise calories for this reason. I just have a high goal and a low goal and I don't worry if I go over sometimes, only if I don't eat enough. I feel my heart rate go up and I sweat my butt of in Zumba and Turbo kick and step.. BUT I *never stop moving* during class. I even jump up and down in between songs or do jumping jack or salsa (where I touch the floor on the backwards step) or something.. My resting heart rate last time I was measured was about 52.. but my heart rate jumps way up when I work out or even when I just walk to work (jumps to like 80 when I walk to work and anywhere from 120-190 when I work out) and as soon as I stop it immediately drops (hence the jumping in between songs lol) I also swim and weight lift.

    So.. unless I buy a chest strap.. which I have no real inclination to do at this time.. I just guess :)
  • beezee178
    beezee178 Posts: 5
    If you're not counting calories as such I guess it doesn't really matter anyway! I never thought about it too much until I started talking to my neighbour which has piqued my interest.

    Completely agree with the never stop moving bit. I'm bouncing around constantly too if I do go to classes at the gym. All the exercise I do outside the gym isn't the kind where you have the opportunity to stop anyway.

    Confuzzled4ev - I have never looked into it too much but I think that is a good thing re your heart rate too. From memory the two important bits are a low RHR and how quickly it drops back to normal after exercise has finished. The rest isn't quite as important from a health perspective (but I could be wrong!).

    I have only just started using the chest strap while I do other kinds of exercise (mainly due to my sudden interest in heart rate and calorie burn from different kinds of exercise). I have always used it for running simply because I use target heart rates for distance training ... and I'm a geek and I love all the little stats that pop out on my computer :)
  • Confuzzled4ever
    Confuzzled4ever Posts: 2,860 Member
    Lower heart rate is good. Means your heart muslce is stronger and is pumping more blood per squeeze then it was before. Means your body has to work less to maintain itself. Also means you burn less then your neighbor who's heart muscle has to work harder to get the same amount of blood out to thier organs and you can most likely do more then them without becomming fatiqued.
  • Meaganandcheese
    Meaganandcheese Posts: 525 Member
    Yup, when I first started turbo kick classes, I would burn 900+ cals in the hour class (according to my HRM). It's a great workout - my favorite form of cardio!

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