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For the same level of perceived exertion (i.e., the work feels the same during both activities), running will burn more calories than the elliptical, although it's pretty close (about 100 calories per hour difference). Some of the difference is due to the pounding of running and the fact that you propel your body through the air so that both feet are off the ground simultaneously. This kind of movement takes lots of energy. Both the elliptical and running burn substantially more calories than the bike at the same level of perceived exertion (about 200-240 calories per hour more).
In a classic study comparing energy expenditure of exercise machines, the order of calories burned, from highest to lowest, is posted below. (The elliptical was not studied in this research, but it would fit between rowing and cross-country skiing. It should be noted that rowing, the elliptical, and cross-country skiing are all very close in calorie expenditure, with probably not more than 100-125 calories per hour difference among them.)
- treadmill walking/running
- stair stepping
- cross-country skiing
- biking (stationary)
Now, this is not to say that exercises that burn the fewest calories are all bad. To the contrary, you can get a great workout, and burn lots of calories, doing any of them. You'd be hard pressed to say that Lance Armstrong isn't fit. He's one of the fittest human beings alive, and he did it by biking. The point is that if you work hard enough on any of the exercise machines, and you work up a sweat, and you get your heart rate into your training zone, then your heart, lungs, and muscles aren't going to know the difference. Bottom line is that you'll get fit and healthy using any of the machines if you use them consistently and with sufficient intensity.
One final note: There is error in estimating energy expenditure on most, if not all, exercise machines. In some cases, it can be as high as 25 percent (the machine overestimates how many calories you burn). There are simply too many variables for the machine to give you an accurate number, and so you need to keep that in mind during weight-loss efforts if you are calculating how many calories to eat based on your energy expenditure.
Medically reviewed by Robert Bargar, MD; Board Certification in Public Health & General Preventive Medicine
"The benefits and risks of exercise"