NEW YORK - If you're a runner, you might have noticed this surprising headline from the April 5 edition of The Guardian: "Brisk walk healthier than running - scientists." Or maybe you saw this one, which ran in Health magazine the very same day: "Want to lose weight? Then run, don't walk: Study."
Dueling research from rival academic camps? Not exactly. Both articles described the work of a herpetologist-turned-statistician at the Lawrence Berkeley National Laboratory named Paul T. Williams, who, this month, achieved a feat that's exceedingly rare in mainstream science: He used exactly the same dataset to publish two opposing findings.
One of Williams' papers, from the April issue of Medicine & Science in Sports & Exercise shows that habitual runners gain less weight than habitual walkers, when the amount of energy they put into their exercise routines is the same. The other, published in April in Arteriosclerosis, Thrombosis and Vascular Biology, used a similar analysis to show that running is no better than walking when it comes to the prevention of high blood pressure, high cholesterol, diabetes and coronary heart disease. So there you have it, and there you don't. Running is better for your health, or perhaps it isn't.
Despite the flip-flop headlines, the findings are not as contradictory as they seem. Losing weight is not the same thing as getting fit so there's no fundamental reason why Williams' walkers couldn't gain more weight than the runners while their risk for cardiovascular disease remained the same.
The 47,000 people involved in Williams' study were drawn in large part from middle-aged subscribers to exercise magazines who agreed to fill out his surveys.
The deeper story here has more to do with Williams' second finding, that neither form of exercise was any better than the other at promoting cardiovascular health.
When Williams set up his gigantic database of avid runners and walkers in the early 1990s, he hoped to help resolve an old debate in exercise science: If you match up workouts according to the amount of energy that they require, are all forms of physical activity created equal? Would a tough and sweaty workout be any better for your health than an easygoing one that lasted twice as long?
Researchers began to ask these questions in the early 1980s in response to worries over the health effects of jogging. In two decades, the number of self-identified runners in the nation had grown from 100,000 to 30 million. The trend for walking reached its stride in 1986, with nearly 20 million participants.
The Centers for Disease Control and Prevention equalizes workouts of varying intensities according to a standard exchange rate of 2-to-1: Every two minutes we spend hoofing around in Rockport ProWalkers equates to a single minute spent on the jogging trail.
That means people can mix and match their workouts until they approximate a recommended weekly total: Either 75 minutes' worth of sweaty, vigorous workouts, or a double helping (150 minutes) of something moderate - or any custom combination of the two.