Real calories burned on elliptical?

[sweetbecky]

I'm 29, 150 lbs, and I did 65 minute intervals on a Precor elliptical today. The display said I burned 677 calories. This can't be accurate. Anyone know how "off" these machines calculate? Is there a way I can take my average heart rate and figure out a more realistic rate of calorie burn?

[imperfectly_lou]

You're right... elipticals are incredibly inaccurate, even more so than other pieces of cardio equipment.

I use a HR monitor which is much more accurate. To give you a rough idea, this is approx what I burn (5"6.5, 122lbs)

40mins eliptical - 240cals
60mins very hard workout e.g. Body Attack or Tae Bo - 400cals
20 mins HIIT on treadmill plus 5 mins warm up and 5mins cool down - 220cals

[Eyes Open]

Well, 150lbs and 5'6" burns 680 calories an hour at 15mph (that's a cadence of 75 to 80rpm).

The faster the cadence, the more cals you burn because your heart rate increases. The heavier you are, the more you burn. If you're taller than 5'6", then you've burned more.

I use the "ski machine" at http://caloriesperhour.com/index_burn.html to estimate elliptical calories.

[dressagerulz23]

we also have Precors (EFX's) whatever you want to call them and they've always been dead on... actually what i've heard is that they're based on a 150 lb person so i just multiply x cals burned/150 X 111 (my weight)... but when i actually set it for my weight it says i've burned WAY more... assuming a linear relationship the # cals burned for a 150 lb person should be correct, but i have heard its off for that weight. lucky at my weight (anywhere from around 100 to as high as 117/118, the "conversion" method has always been accurate

[not_so_fast]

I'm pretty sure these are a bit more accurate than people give them credit for. Unlike a treadmill the elliptical trainer can measure your work output since the rotational force can be measured. I kept hearing that people were claiming the inaccuracy of these machines so I paid attention to my wattage measurement throughout the workout.

Approximate Wattage Over 1 Hour = 200
Machine Estimated Calories burned = 860
1 Watt = 860.42 calories Per Hour = .86042 Calories Per Hour
200 Watts = 172.084 Calories Per Hour

(For the record this was on a Precor elliptical with an incline value of 8 and resistance set to 10.)

However your work expenditure to work output isn't a 1:1 ratio. In fact, for professional athletes it's a 5:1 ratio. Meaning that in the best case you're working five times harder than what's actually being produced. So if we take the previous number and multiply it by 5

172.084 * 5 = 860 Calories

Now it could be that the computer is adjusting the Wattage measurement but I'm skeptical that it does. I did some mild research on bicycle power generators and some of them claim an adult can produce up to 400 watts of power, well over my 200 watt average.