Don't Count on Calorie Counters

Jan. 14, 2008 — -- It's January, and for most of us, that means going back to the gym to sweat off those holiday pounds. But if you're using the gym machines to count your calories, you're in for a big surprise.

Many rely on calorie counters in their quest for the perfect body, but unfortunately it's not an exact science and the numbers you're seeing are not the whole truth.

For 54-year-old Cynthia Goldberg, 600 is the magic number of calories she wants to burn to erase Sunday night's dinner.

"I had some wine, had some pasta, so that's on here now so I've got to work it off," she said. "I really try to see the numbers to know that I'm on the mark."

Can't Always Trust the Numbers

Doctors say though that the numbers don't add up.

"There is absolutely no way those machines can accurately determine the amount of calories that they burn," said weight specialist Mitchell Roslin.

Roslin says most machines overestimate the number of calories burned by 10 percent to 30 percent— some as high as 50 percent.

Goldberg was not shocked to hear the news. "That's why I haven't been able to get this off," she said with a laugh.

Most machines also don't account for body fat. For example, if two people weigh the same, the one with more fat will burn fewer calories than the person with more muscle mass.

Mal McHugh from the Nicholas Institute of Sports Medicine says beyond calculating this complicated mathematical formula, there's really no way to be sure exactly how many calories you're burning: "It's not that simple."

Experts agree that some counters are better than others: weight-bearing machines like treadmills and Stairmasters are more accurate than stationary bikes that don't factor in weight.

What You Can Do

The way to get the most bang for your sweat is by using a heart monitor. The goal is to reach a breathing intensity where you can still carry on a conversation but with some difficulty, then note your heart rate at that level.

Once you've found your zone stick with it for 30 to 40 minutes and you'll maximize the number of calories and fat you're burning on any piece of equipment.

"If you do this consistently, cumulatively you'll end up with the results that you want," said Reebok trainer Nicki D'Atellis.

To keep your calorie count as accurate as possible also avoid leaning on the handles, which can actually reduce the number of calories you're burning by up to 50 percent.

Try and mix up your workout, too. The more familiar your body becomes with one machine the fewer calories you're going to start burning at the same effort level.

If you're hooked on the counters like Goldberg, enter a lower weight into the machine than your own to compensate for that margin of error. As soon as she saw those numbers, she said, "I just feel a whole lot better."

The Skinny

Manufacturers say the counters aren't exact, but are meant to serve as a general measurement tool based on scientific formulas, and a way to gauge your performance from workout to workout, from machine to machine.

"Exercise science recognizes a number of dynamic factors that influence individual calorie burn beyond time and distance on a machine — factors including fitness level, level of exertion and heart rate, biomechanical efficiency and diet. … It's not realistic to expect a cardio machine to be capable of presenting highly accurate, individualized performance metrics," a spokesperson for Precor fitness equipment said.

Cybex International Inc. weighed in saying that the calculations in its machines "are based on large population studies that use male and female subjects of a variety of ages, sizes and fitness levels. … The relative accuracy depends on how similar the individual is to the 'typical' individual. So while the calorie count may not be absolute, it is an excellent metric of the amount of work done."

Exercise gear manufacturer Nautilus also said that its machines are calibrated to count calories according to industry standards.