SPU Researcher Leaves Old Theories About Burning Calories in the Dust

The science of running

Cara Wall-Scheffler and her colleage discovered that each runner has one speed that costs the least amount of energy.

It sounds like a question from the dreaded “Human Anatomy” exam: Which runner burns more calories during a five-mile race? (a) The runner who finishes the course in 30 minutes. (b) The runner who finishes the course in 60 minutes. (c) They both burn the same amount of calories.

For years, scientists (and runners) believed the correct answer was “c.” Fast runners burned calories quicker, but finished sooner. Slow runners burned calories at a gradual pace, but ran longer.

But recent research by Seattle Pacific University Assistant Professor of Biology Cara Wall-Scheffler is shedding new light on this old theory. Wall-Scheffler, along with University of Wisconsin Professor of Zoology Karen Steudel, concluded that there is actually one speed at which each person burns the fewest calories. The research was published in a recent edition of the Journal of Human Evolution, a peer-reviewed scientific journal.

For their experiments, the researchers collected data on nine people running at a series of self-selected speeds ranging from 4.5 mph to 11 mph. Each person ran six different speeds; two slow, two comfortable, and two fast. The researchers measured how many calories the runners burned at each speed. To ensure the quality of the results, each runner repeated all speeds multiple times.

“What we found, and what had never been found before, is that each person had one speed that cost them the least amount of energy,” says Wall-Scheffler. This speed was the “medium or optimal” pace for each runner. The average optimal speed for women in the study was 6.5 mph; for men it was 8.3 mph. Runners who ran slower or faster than their optimal pace burned more calories.

Not only were Wall-Scheffler and Steudel surprised by their findings, they were surprised that they were the first to make the discovery, which has been widely reported in sports and running journals, blogs, and even on Late Night With Jimmy Fallon.

“We think part of the reason we are the first to detect this strong correlation is because we’re really the first to statistically test it,” says Wall-Scheffler. “We used a very good design with very sensitive measuring equipment.”

What do these findings mean to the average runner trying to lose weight, or for the marathoner needing to run long distances?

“It seems that people who are trying to lose weight may run more slowly anyway, so it will be good for them because they burn a lot of energy running slowly,” explains Wall-Scheffler. For the long-distance runner, she says running at their optimal pace will be more efficient and burn less energy.

And how does a runner find their “optimal pace”?

SPU Cross Country Coach Erika Daligcon says this can be “tricky,” but she employs some of the same techniques Wall-Scheffler used in her research. “Three speeds a week is what I prescribe for runners for gains in fitness, fortitude, and most importantly, fun,” says Daligcon. “If you don’t try a different speed, you’ll never know what feels best.”

—Photo by Sarah Rhoads


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