New here - question about fitness machines and calorie counters

I wasn't able to find any threads on this...maybe I didn't look hard enough?

Anyway - Just how accurate are the calorie counters on the fitness machines found in gym's?  For example, I use a Life Fitness Eliptical machine for my workouts.  I typically go for 45-60 minutes, at an average of 4.5 mph.  The calorie counter says I burn about 550 - 575 calories on average for each workout.  When I log my exercise on here, the calorie count is much higher, almost by 100 calories it seems.

Is the eliptical machine that far off or am I logging my exercise incorrectly on this site? 

I understand some fluctuation...calorie counting is not an exact science.  However a +/-100  calorie difference seems a bit much. 

Any insight? 

I've wondered about the accuracy of machines too...I do know that the more information you enter, the more accurate it will be.  Muscle tone also affects the rate at which you burn calories, more muscle = faster burn rate.  Also, if there aren't any sensors for you to hold for the machine to take your actual heart rate, its hard to be accurate w/ how much you personally burn.  Heart rate, height, weight, and age all affect how many calories you actually burn.  So, it's a tough call. Hope that helps some though..:-)

I use the elliptical also for 60mins. The max i ever burn is 415cal. I suppose it sometimes depends on the speed your going at. Im not sure.

The Precor ellipticals use your weight and wattage generated to determine calories. Wattage is basically speed and resistance. Other machines I don't know.

 

Alas,  I like to take the lower numbers. 

hey james,

it drives me nuts to have no clue how many calories i'm burning.  how are we supposed to COUNT calories that're so ambiguous?! 

things get even trickier when your cardio is several hours long (did i burn 1500 calories or 2100?).  i've been trying to work backwards on this issue, by seeing how many calories i'm eating and if my weight goes up/down.  it's nearly impossible, tho, bec i seem to maintain my weight no matter what.

I seem to jump into these threads all the time, and dbackerfan won't be too far behind.  I'd recommend you investing in a good heart rate monitor.  I have a Polar F11, and I don't know how I ever lived without it.  It is by far the best fitness investment I've ever made.  I don't feel the chest strap, and it takes far more information into consideration when calculating the number of calories I've burned in comparison to the machines at the gym. 

hey pixy,

thanks for the advice.  when doctors check my heart rate they often ask how i walk up a flight of stairs (it's low).  i've always been so terrified that i'm SO fit that a heart rate monitor would reveal that i'm only burning a third of what the machine reads. 

i am working really hard, though, when i do cardio, which gives me some assurance that the energy/calories are coming from somewehre.  i wish calorie burn were based on dedication!

the more information you enter on the machine (weight, age, etc.) the more accurate it will be. ellipticals tend to over judge by just a little bit, treadmills are normally pretty accurate. i'd go off the machine, not this site if you're entering your information.

 Actually, the counters on the machines tend to over-estimate by 24%-32% according to the latest findings in Journal of Sports Medicine.

  If you're really concerned, get a heart rate monitor - it's the only thing that'll be reasonably accurate.

I'm another fan of the Polar HRM...I have an F6, and it's great for calorie counting.  Defintely get one if you want a true idea of what you burn....my elliptical was WAY off....but my treadmill was reasonably close. 

Machines are all over the map. Some are ridiculously low, and some are way optimistic.

If you can find a machine that will tell you your average wattage, then you can compute your calorie burn using that and your time. 1 Watt is 1 Joule/sec, so multiply by seconds to get total Joules. Figure 75-80% of your total burn is wasted as heat, and only the remainder is actually measured by the machine, so your total burn will be more like 4x what the machine measured for your power output.

Finally, it's 4.19kJ/kcal.

Thanks for all the great information folks!  It is much appreciated!

Good thread you guys have here. I also very much confused as to how much calories are burned. I read a different thread on treadmils and some say the calorie counter is pretty accurate if you enter age and weight.

So today I ran for 5K at avarage speed of 6.5 mph, the machine showed 380 calories burned, while heart monitor showerd only 270 calories. I then did precor free motion machine at the highest resistance, and it showed 400 calories in 30 min and my monitor showed 330....

So the delema is what is right. In both machines i could see the accurate level of my heart rate (when compared to watch)?

When i read JamesStreck's thread it made sense that if your resistance is higher you use more energy, so the machine uses this equation - which means it should be pretty accurate? The reason i keep typing on this subject is that i dont understand what is more accurate the machines or HRM? they are off by 200 calories after 60 min training session - I think it is a bit too much... :(

THis kinda thing drove me nuts until I bought a GOwear Fit.  Now I always know exactly what the burn was :)

How do you know the GOwear fit is accurate?

Original Post by balashka:

The reason i keep typing on this subject is that i dont understand what is more accurate the machines or HRM? they are off by 200 calories after 60 min training session - I think it is a bit too much... :(

 Use your heart rate monitor.  It is consistent, and a much better indicator of calorie burn than the machines.  I've used every dang machine in the gym, for times that would give the same burn on my HRM, and every machine gave a DIFFERENT number.  They are always too high, and always inconsistent.  My Polar F6 has worked well for me.