How Many Calories Are You Really Burning?

If you think running and walking both torch the same number of calories per mile, you better put down that cookie.

July 18, 2005
Media: How Many Calories Are You Really Burning?

A few months ago I got into an argument with someone who's far smarter than I am. I should have known better, but you know how these things go. Needless to say, I lost the argument. Still, I learned something important in the process.

David Swain is a bicyclist who likes to ride across the country every couple of years. Since I spend most of my time on my feet, I figured I could teach him something about walking and running. Perhaps I should have paid more attention to Swain's Ph.D. in exercise physiology, his position as director of the Wellness Institute and Research Center at Old Dominion University, and his work on the "Metabolic Calculations" appendix to the American College of Sports Medicine's Guidelines for Exercise Testing and Prescription.

Both Swain and I are interested in the fitness-health connection, which makes walking and running great subjects for discussion. To put it simply, they are far and away the leading forms of human movement. Every able-bodied human learns how to walk and run without any particular instruction. The same cannot be said of activities such as swimming, bicycling, skateboarding, and hitting a 3-iron. This is why walking and running are the best ways to get in shape, burn extra calories, and improve your health.



What the Numbers Show

I was still gathering my resources for a retort when a new article crossed my desk, and changed my cosmos. In "Energy Expenditure of Walking and Running," published last December in Medicine & Science in Sports & Exercise, a group of Syracuse University researchers measured the actual calorie burn of 12 men and 12 women while running and walking 1,600 meters (roughly a mile) on a treadmill. Result: The men burned an average of 124 calories while running, and just 88 while walking; the women burned 105 and 74. (The men burned more than the women because they weighed more.)


Now that you understand why running burns 50 percent more calories per mile than walking, I hate to tell you that it's a mostly useless number. Sorry. We mislead ourselves when we talk about the total calorie burn (TCB) of exercise rather than the net calorie burn (NCB). To figure the NCB of any activity, you must subtract the resting metabolic calories your body would have burned, during the time of the workout, even if you had never gotten off the sofa.

You rarely hear anyone talk about the NCB of workouts, because this is America, dammit, and we like our numbers big and bold. Subtraction is not a popular activity. Certainly not among the infomercial hucksters and weight-loss gurus who want to promote exercise schemes. "It's bizarre that you hear so much about the gross calorie burn instead of the net," says Swain. "It could keep people from realizing why they're having such a hard time losing weight."
