Are Precor EFX Machines really as effective as the calorie readout tells me?

February 17, 2006 5:44 PM

Are Precor EFX Machines really as effective as the calorie readout tells me?

I regularly use a precor EFX machine at the gym and am constantly amazed at the amount of calories it says I'm burning. (eg. 450 kCal in 30minutes). From what I understand this is equivalent to running at a very decent pace for an hour. The reason I question this is because there's no way I could work of that amount of cals/min on any other machine or method without falling over in about 5 minutes. On the EFX my heart-rate and breathing are increased but not to the equivalent of even running on a treadmill for 5 mins at 5mph (I'm a crap runner btw).

At the begining of my workout I always put in my correct age and weight.

Is the EFX telling me the truth? If not, what would be a more accurate way to measure energy expenditure?

posted by mule to sports, hobbies, & recreation (6 comments total)

No. It is making a wild ass guess based on your weight and age. If you wear a heart rate monitor and figure out how many calories burned that way [with the watch thing, or doing the math at home], you'll get a better idea.

It would be cool if the machine took your heart rate into account, but it doesn't.
posted by birdherder at 5:53 PM on February 17, 2006

No. If you want accuracy, get a heart rate monitor. I have a Polar F11 and i love it.
posted by makonan at 6:19 PM on February 17, 2006

The reason the Precor machine's readout is so much higher than other machines (and higher than what makes sense) is because they include the basal metabolic rate in the figure.

In other words, they include the calories you would have burned anyway, without the exercise.

It's dumb and maybe even dishonest, but I'm sure it encourages at least a few people to buy them because "they burn calories so much faster than x brand!"

You could probably calculate your BMR (i'm sure 100 calculators for this exist online) and subtract that from whatever the machine's readout says.
posted by helios at 7:11 PM on February 17, 2006

by the way, how can a heart-rate monitor be used to calculate how many calories you burn? Aren't different hearts different sizes?

Nevertheless, your results are pretty similar to what I got on a Life Fitness eliptical.
posted by delmoi at 8:02 PM on February 17, 2006

delmoi, that just demonstrates that all of the calculations that you see on gym equipment are bogus.
posted by fixedgear at 3:17 AM on February 18, 2006

these instruments include your BMR
posted by NucleophilicAttack at 4:17 AM on February 18, 2006