Burning Calories

The number of calories burned that is noted by various cardio machines is only an estimate. A rule-of-thumb for an average size person walking or running is 100 calories a mile. If your machine says you burn 200 calories in half an hour, that would be equivalent effort to walking two 15-minute miles. Calorie estimates on treadmills and bikes are probably more accurate than on other equipment. Changing the resistance on an elliptical should not make a dramatic difference in calories burned. The best thing to do is to concentrate on your effort level and feel you've had a good workout at the end.