Feeling good about the bright red numbers on the display of the treadmill that boastfully proclaim that you’ve burned 578 calories on your epic run? Don’t get ahead of yourself — According to the Chicago Tribune, recent studies show that the number of calories that fitness machine says you worked off could actually be off by quite a bit. As in, as much as 30 percent off. So you may have only burned 405 calories — not even enough to burn off that bagel sandwich you had for breakfast!
Truth is, those gizmos and gadgets at the gym can only make an approximate guess at how many calories you’re burning. Some say the only real way to get an accurate measure of your caloric burn is by monitoring the heat produced by your body in a specially-designed lab, and that’s just not practical. So instead, your calorie burn is guesstimated by taking a few different factors into consideration — your weight, your heart rate and/or your oxygen consumption. In most cases — or at least with the ones I’ve used — machines at the gym only take into account your weight and sometimes your age and use that to determine your calorie burn based on averages. The result, as you might imagine, is not always reliable.
So how can you get an accurate reading on your workout? Some experts recommend the Body Bugg, which measures both your motion and the amount of heat you’re giving off. But there’s no device out there that’s 100 percent accurate, so you might want to forget about calorie counts and instead focus on making sure you feel challenged at every step of your workout.