Exercise Machines and Calories
I ran across this article by Julie Deardorff in the Chicago Tribune today, which discusses the accuracy of the calorie counters on cardio machines…the take home is that you may not be burning as many cals as you think you are, depending on the machine you use…
“The bicycle predictions are the easiest to make, because the variation in people’s mechanical efficiency is relatively low, and it’s very easy to convert work [in watts] into calories, given what we do know about cycling efficiency,” said exercise physiologist Ross Tucker, co-author of the exercise science blog The Science of Sport, sportsscientists.com.
On the treadmill, the efficiency of an individual’s stride is more variable, Tucker said. “Assuming you’re within 5 percent of the ‘true value,’ if your reading says you burned 600 calories per hour [or 10 calories per minute, a fast walk or slow run], then your range is probably within about 570 calories to 630,” he said.
Unlike the treadmill, there are no standardized equations for caloric count on elliptical machines, said Doug Durnford, a senior product manager with Precor, which manufactures fitness equipment. So the accuracy “depends on the amount of due diligence performed by the manufacturer.” Precor has funded a study looking at whether its equation—which measures calories using gas exchange measurements—is valid.
In other words, the counts on an exercise bike are fairly accurate; treadmills are sorta accurate; and ellipticals…well, it could be an “elliptical illusion.”
This is not to say that certain machines should be shunned – “not accurate” doesn’t mean “no good” – in fact, I like ellipticals and feel I get a pretty good workout from them. But I just don’t bother with the calorie counters to tell me how hard I’m working…or how hard I should be working.
