Tuesday, August 19, 2008

Good Question: Do Treadmill Calorie Counts Work?

“On the treadmill or the elliptical machine it's the one number on the display that can keep you moving: The calorie count. But how can a machine know how many calories we're burning? ‘Well, it's an estimate,’ explained Beth Lewis, Ph.D., an Assistant Professor of Kinesiology at the University of Minnesota's College of Education and Human Development. Lewis acknowledged that while she works out she consults a calorie counter on a watch that monitors her heartbeat, although, ‘I take it with a grain of salt,’ she said. Each manufacturer uses a different formula to calculate the calories burned. Some, like Precor USA, say they created the formula in consultation with the American College of Sports Medicine. Generally, those formulas include weight and age of the athlete, along with speed of the workout and incline or intensity level. But, according to Lewis, there are many other factors that the machines do not factor in to their formulas. ‘Genders often not, like I said body fat, your metabolism rate, how long you've been doing the machine, how efficient you are. Those are kind of the major variables that could play a role,’ she said. According to WebMD.com, machine calorie counts tend to overestimate by 10 to 15 percent, at times they can overestimate by as much as 50 percent. If the calorie readout indicates that you've burned 300 calories, it's possible you've burned closer to 265 calories. Either way, Lewis recommends that you don't take that number as an invitation to consume those calories as a reward for your workout.”


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