How accurate is the treadmill at your gym that showed that you burned 400 calories during your workout? Chances are that number is skewed.
Most cardio machines only allow you to enter the first three variables—your gender, age, and weight but a person’s caloric expenditure can vary based on gender, age, weight, and fitness level.
Your fitness level takes into account your health, aerobic capacity, metabolism, and ratio of muscle vs. fat and plays a major role in how many calories you’ll burn during a workout.
For example, a 200 pound, 30 year-old male who runs marathons and has a 12 percent body fat percentage is going to burn far fewer calories than a 200 pound, 30 year-old male who rarely exercises and has a 22 percent body fat percentage, assuming they do the same exercise for the same amount of time.
Your body becomes more efficient at performing exercise as you get better in shape and therefore you end up burning fewer calories for the same activity.
So how much variation is there in cardio machines? In one University of California, San Francisco experiment conducted for Good Morning America, elliptical machines were found to be overestimating one exerciser’s calorie expenditures by 42 percent. Treadmills overestimated by 13 percent, stair climbers by 12 percent, and stationary bikes by seven percent. Newer machines tended to be more accurate.
Tip: Do more each time — Each time you step on a machine, try to increase either your intensity or your exercise time. And vary your workout with different machines.