Many exercise equipment advertisers make bold claims about their products’ benefits – claims that should be taken with a grain of salt, according to an expert in the September/October issue of a journal of the American College of Sports Medicine.

David Swain, Ph.D., FACSM, says if an assertion sounds too good to be true, it probably is.

"There is still no ‘miracle machine’ that will give you the body of a fitness model in just a few minutes per day," Swain said. "The tried-and-true machines that have been around for the longest, like treadmills, have remained staples of the fitness industry for a reason."

Swain says consumers should be especially wary of these claims:

Excessive calorie burn. It’s impossible to burn, say, twice the number of calories on a specialty machine as on a treadmill. The body has a natural limit on how many calories can be burned in a given exercise session.

Fitness fast. Brief bouts of high-intensity exercise can improve maximum power more than low-intensity exercise, but cannot improve all areas of fitness in just a few short minutes.

"Fat-burning" zones. According to the intensity zones on some machines, you don’t have to work as hard to burn fat. But Swain says that weight loss – or what some interpret as "fat burning" –comes from total calorie expenditure. It’s the combination of intensity and duration that counts.

Waist reduction. Spot-reduction is a fantasy, Swain says. Machines that only train the abdominal muscles won’t remove fat from the stomach; only total-body exercise and weight loss willeventually yield those results.

In addition, Swain notes that many machines’ reported caloric expenditures are inflated. Most inflate the calories by including resting energy consumption, and use of the machine is a big factor in calorie burn. For example, holding on to the handrails of a steeply inclined treadmill reduces calorie expenditure – but the calorie report on the machine doesn’t reflect that change.

"Exercisers should focus on overall health and accumulating at least 150 minutes per week of moderate-intensity activity, or at least 75 minutes per week of vigorous-intensity activity," Swain said. "More is needed for weight loss, but the real benefits of exercise are decreased risk of disease and improved quality of life."

The public can find tips for meeting the physical activity recommendations at www.acsm.org/physicalactivity.