Fitness Minutes: (30,920)
479 8/4/13 9:56 P
That is interesting info about calorie burn being greater in the first 10 minutes. Thank you.
Whatever the calorie burn, I'm going to keep doing my kettlebell workouts. They are fun and I'm already seeing muscle definition after only three weeks. Imagine how much stronger I will be in another month!
The body has several different energy systems. The anaerobic (without oxygen) energy system is capable of burning calories very quickly, but lasts only a short time.
The aerobic (with oxygen) energy system can last much, much longer, but the ability of the body to deliver oxygen to the muscles is a real choke point and calorie burn figures above 13/min should be regarded with a great deal of suspicion for anyone but an elite athlete.
For short duration exercise, it is possible to burn 20 calories/minute, because you are using a combination of anaerobic and aerobic energy systems. But once you get beyond about 10 minutes, you will have exhausted the anaerobic energy system, and will be relying on the aerobic system (and its constraints) only.
This is the reason a 100 meter sprinter runs much faster than a marathon runner.
Extrapolating from 20 cal/minute for a short duration kettlebell workout, to burning 1000/1200 calories in an hour is NOT a reliable estimate.
I have kettlebell DVD's that are 20 minutes long and the estimate is 400 calories per 20 minutes. It also depends on the weight of bell you are using (I use a 15lb) and the velocity it is swung. 20 minutes is probably the max someone/beginners would want to do this as it is quite intense.
Fitness Minutes: (30,920)
479 8/1/13 11:55 A
The only reason I even care about trying to estimate calorie burn for this is that several members here and the Spark Dietitician suggested I might not be eating enough for the amount of exercise I do. So I increased to 1300 cals but gained a pound this week!
ZORBS, you are right that there are some rows, presses, etc in the class. Mostly we do them in combination with squats or lunges.
Edited by: RAVELGIRLY at: 8/1/2013 (11:56)
Fitness Minutes: (3,530)
337 8/1/13 11:50 A
Yes, that is Correct, you can burn 20 calories a min. with kettlebells!! I love this exercise. Those that tell you its Not true have probably never picked up a kettlebell. I keep calorie track on my watch . Good Luck and keep burning all those calories with your kettlebells!! :]
Fitness Minutes: (113,430)
13,569 8/1/13 5:13 A
I think the class would THEORETICALLY be 1000+ cals/hour IF:
a) your movement is continuous. There HAS to be rests during KB class. You can't do swings or something for 60 minutes non-stop.
b) if you did nothing but cardio-type moves (swings, cleans, snatches) continuosly as stated above. I'm willing to bet the class has some rows, presses, TGUs, windmills, squats thrown in there too, which is most definitely ST and not cardio.
Otherwise, I stand by my recommendation to track it as strength training.
I'm not sure of the basis for the 1000/hour claim.
If it is based on an HRM reading, unfortunately, your heart rate is not a good predictor of calories burned for strength training, in the way that it is for cardio.
An HRM will not produce accurate calorie estimates for strength training. And kettlebells are strength training.
Fitness Minutes: (91,827)
2,061 8/1/13 2:49 A
I use heart rate monitor and my burn differs between 280 - 330 calories for 50 min workout.
Fitness Minutes: (30,920)
479 8/1/13 12:47 A
Thanks for the detailed information, Coach Dean.
You're right that the same level of intensity isn't sustained for the entire hour - we have to change equipment, grab a quick gulp of water, etc.
Those calculators are a bit depressing because they put my RMR at 1,316 calories. Which would mean that in an hour of kettlebell class (which includes push ups, sit ups, etc) burns somewhere between 195 and 440 calories! Argh! That's not a lot of return for my "sweat equity" but I suppose strength training yields more benefits than just calorie burn.
Interestingly, Sparkpeople's own tracker lists 1200 calories as the estimate for kettlebell training.
Fitness Minutes: (166,084)
15,139 7/31/13 8:58 P
It's EXTREMELY difficult to burn 1200 calories/hour unless you're a very large, extremely fit, heavily muscled athlete doing a very intense exercise that you can actually sustain for the full 60 minutes. That study about calorie burning during kettlebell workouts that was linked in one of the earlier posts in this thread says, for example, that the subjects did burn 400 calories in a 20 minute workout. That would translate into a calorie burning rate of 1200 calories per hour--but only IF the subjects could actually maintain that level of intensity for the full 60 minutes. Very few people can do that, and those subjects didn't.
Most of us ordinary mortals doing an exercise that we can actually maintain for 60 minutes aren't working at nearly the kind of intensity level that it would take to burn 1200 calories. Typically, we might work that hard for brief intervals during a high intensity interval training type of cardio workout, or for several fairly brief intervals during a very vigorous strength training workout. But if you spend a significant amount of your time doing lower intensity intervals or resting during your workout, that's going to lower your total calorie burn dramatically.
Here's a good way to check the validity of claims about hourly calorie burning rates for various activities that you might do, and also to get an idea of whether exercise trackers or on-line programs for estimating exercise calorie burning are giving you a realistic estimate.
Start by using a standard formula or calculator for estimating your resting metabolic rate. That's the number of calories someone your age, weight and gender would likely burn in 24 hours if you do nothing but lay in bed all day. Here's a good website with a calculator like this:
Then take that total 24-hour figure and divide it by 24 to figure out your hourly rate. That's how many calories you burn in an hour of laying in bed. Now you need to figure out how to add your extra calorie burn from exercise to that number. A standard, generic approach for doing that involves the Metabolic Equivalents (METS) formula, which is the same formula that most on-line trackers and exercise machines rely on. Some scientists looked at a lot of different kinds of activities and assigned MET values to them based on values seen in large groups of people. Laying in bed has a MET level of 1, while (for example) moderate walking on a flat surface at 3 miles/hour has a MET value of 3.3, while running at a 6 minute mile pace might have a MET value of 7 (these aren't necessarily the actual MET values for these activities--just an illustration). This means that you'd be burning 3.3 times your resting metabolic rate while walking at a moderate pace, and 7 times your RMR while running at 10mph. So, for example, if person A had a resting metabolic rate of 2400, that would be 100 calories per hour; and that means Person A would be burning 300 calories per hour when doing an activity with a MET value of 3, or 700 calories per hour with an activity with a MET value of 7.
Here's a link to a Wikipedia article that explains all this in a little more detail, and also includes links to a Compendium of Physical Activities which gives the MET values usually assigned to many common exercises, activities, and intensity levels:
Now, here's how you can use all this to do a quick reality check when you see claims about how many calories/hour you're going to burn when doing a particular workout. I'll use myself as an example. As a 202 pound, 65 year old male who is 6'2" tall, the RMR calculator linked above tells me my resting metabolic rate is very close to 1800 calories for a 24 hour day, or 75/hour. So, for me to burn 1200 calories in one hour, I would have to be doing an activity with a MET value of 16 (16 x 75 = 1200). Not humanly impossible, exactly, but pretty close, at least for me. Typically, moderate intensity cardio has MET values in the 3-6 range, high intensity is 7-10, and competitive athletic competition might get you up into the 12-16 MET range. So, for me to burn 1200 calories in an hour, I'd need to be able, essentially, to give Michael Phelps a real run for his money in a full-hour, max-effort swimming race, or do whatever the equivalent amount of effort would be during a 60 minute kettlebell workout. I'll leave you to figure out how realistic that might be.
Obviously, your numbers will be different from this example, based on your age, gender, size and fitness level. But the real-life bottom line is that very few people can burn 1200 calories per hour with any kind of exercise that they can actually sustain for that length of time. For most of us, 600 calories per hour will be much closer to reality for the kind of sustained moderate to high intensity activity we can actually do for an hour. You can probably burn quite a few more calories per minute for short bursts of very high intensity work, life lifting heavy weights for a few minutes, or running very fast up a shortish hill. But you may not be able to sustain that level of effort for an hour, which is what it would take to burn 1200 calories in 60 minutes.
Unfortunately, estimating exercise calorie burn is probably never going to be an exact science, unless and until someone finds a practical way to actually measure it in the moment without requiring that we be hitched up to a machine in a laboratory. In the meantime, I'd be pretty suspicious of any estimate you get from a machine, calculator, or equipment/workout salesperson that says you're burning much more than 600-800 with 60 minutes of effort, unless you're a very well trained athlete working very hard for the full 60 minutes.
Hope this helps.
Fitness Minutes: (85,989)
23,817 7/31/13 6:32 P
I have a couple of these and my 6k doesn't burn that much but as it is ST you can't track it with a monitor.
Fitness Minutes: (113,430)
13,569 7/31/13 5:20 P
I track KB as strength training and don't calculate calories burned.
Fitness Minutes: (85,069)
2,489 7/31/13 5:07 P
Holy cow! I was skeptical at first but I looked into it and all resources estimate around 1000 cals per hour. It's listed in the Spark's fitness tracker and according to them, at 120 lbs I'd burn 1200 cals/hour. Wonder if I'd drop dead before the hour is up...
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