I’m back into working out. My favourite method of burning off the 33 accumulated years of Doritos and Big Macs is the LifeFitness elliptical trainer, which gives me a good workout without wrecking my knees.
In fact, I could probably do an hour and a half a day on this thing. I just love it. My question is, though, how many calories am I burning?
The Lifefitness has a “Calories burned” counter, which rings them up as you go. You enter your weight and age before using it so maybe it counts them based on that too, and it measures your heart rate so maybe that figures into it (the heart rate monitor appears to be very accurate.) I figure it credits me for burning about 13 calories per minute; it appears to vary slightly depending on how vigourously I’m working out, but not very much.
Is this thing actually giving me a good picture of how many calories I’m working off, or is it bull? Am I really burning off 500-550 calories in a 40-minute workout like it claims I am, or is it 200, or a thousand?
My guess is that most machines over estimate how many calories you are burning. IMO, they assume the best possible form, moving your arms to the full degree, etc. which are rarely accurate. As to the degree to which they overestimate, I have no idea.
The only ones that seem fairly accurate in my experience are the Concept II Ergs (rowing machines).
There’s a huge variation in the amount of calories two people of the same age, gender, and weight will burn doing exercise due to differences in body composition and aerobic fitness. Both of those are hard to measure outside of a laboratory, so right there you’ve got some major issues with the calorie meter.
But it’s not too hard to measure the amount of work being done by the person exercising, either by measuring the torque and speed of some rotating part in the machine (or some other measurement, depending on the machine) or it could be related to some calibration (i.e., a speed of ‘X’ at resistance level ‘Y’ is ‘Z’ watts). Add in an estimate of muscular efficiency an you can come fairly close to the actual calories burned.
It would depend on how much effort the manufacturer spent on the calorie counting device. I did not follow any of the links provided. I would guess that a machine that cost several thousand dollars would be more accurate than something sold on an infomercial for 3 easy payments of $29.95.
Power output training (or Watt based training) is becoming fairly common in cycling with the availability of affordable meters that measure the actual power output of the rider. Correlating that to actual calories burned may present variations as ultrafilter said. However, the calorie meter on you machine should be able to give you an idea of your relative power output. Working out at 13 calories per minute should be harder than 10 calories per minute.
Only if you’re working damn hard. Have a look here The only thing that gets over 10 calories a minute is running.
So, nearer 200 I’d say.
BTW RickJay if you can do an hour and a half long sessions then go for it. The best way to burn calories is in long sessions***** not short ones. 1 * 2 hours is better than 2 * 1 hour.
*****I’ll skip the anecdotal evidence and pretend I’ve got solid backup for this
I am going to disagree with Telemark here.
When I exercise I wear a Polar heart rate monitor. It has a function call own cal which measures the amount of calories I have burned. From the link
I often compare the calories burned from my HRM to the machine I am using. I don’t recall ever seeing the machine show more calories burned than my HRM, but it will often show less, a lot less. As much as 50% less. This could be a result of me being a fat bastard, and working like hell to lose weight, I don’t know. But in my experience the machine does not over estimate, it under estimates.
(Hell, they could both be off for all I know, but I feel that the HRM is more accurate.)
YMMV.
The machines give estimates, nothing more. Their designers assume, for a given amount of work, which can be accurately measured, a certain number of calories will be burned, based on a set of assumptions to provide equations of an “average” value. Since virtually nobody fits that average precisely, the machines are virtually never accurate, and deviate from accurate by the amount any given individual deviates from that “average” the manufacturer chose to model from. Even within a class of trainers (ellipticals), the quality of the equipment can have a huge impact on how well the caloric guestimate winds up being.
You can’t get anywhere near an accurate estimate of caloric consumption without knowing things like body mass and body mass index; so can your machine accept these variables as input to modify the output, based on the duration, resistance, and speed of your workout? Also, some workout machines are non-weight-bearing, while others better simulate weight-bearing exercises like running and climbing, which, after all, are impacted pretty dramatically, calorie-wise, by a person’s mass. Do rowing machines do a poorer job than treadmills? I don’t know myself.
Short of having people do their workouts in bomb calorimeters, I doubt there’s any truly accurate means of measuring energy expenditure in the way we would like (“I ate a snickers bar, but burned it off on the treadmill!”). At any rate, the machines give you a more-or-less meaningless number (calories, miles, etc.) taken out of context, but these numbers can be used to guage your performance over time nonetheless.
Me, I record the watts value on my Vision Fitness elliptical trainer when tracking my progress. Why? No real reason, other than I figure that’s probably a reasonably accurate read of the amount of power my workout could provide if I were trying to run an electric motor or something, and hence the number feels more “real”.
Look at the second table in your link, for a 200 lb man doing high intensity arobics burns 153 calories in 10 minutes. This jibes pretty close with what I see from my Polar heart rate monitor. (I’m 205 right now, and high intensity for me is 145-165BPM) So RickJay’s machine might be accurate, course it might not be also.
