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Walkers who feel as though they are way down on the exercise chain can now hold their heads a little higher. When it comes to lowering risk factors for heart disease, walking is just as good as running, according to a new study.
After six years of following a large pool of runners and walkers, researchers found that running lowered the risk of developing hypertension (i.e., high blood pressure) by 4.2 percent, high cholesterol by 4.3 percent and diabetes by 12.1 percent.
But walking was also found to have similar results, lowering the risk of high blood pressure by 7.2 percent, high cholesterol by 7 percent and diabetes by 12.3 percent.
Running also reduced the risk of developing coronary heart disease by 4.5 percent, compared with 9.3 percent for walking. However, the small number of coronary heart disease cases in the study made it difficult to determine if walking and running caused similar reductions in risk, the researchers said.
Researchers analyzed the exercise habits of 33,060 runners enrolled in the National Runners' Health Study and 15,045 walkers participating in the National Walkers' Health Study. Participants' ages ranged from 18 to 80, though most were in their 40s and 50s. Men represented 21 percent of the walkers and 51.4 percent of the runners.
At the study's start, the researchers assessed the amount of physical activity performed by each runner and walker — using distance, rather than time, as a gauge — and calculated the amount of energy each person expended. To calculate energy expenditure, which correlates with intensity, the researchers used a measure called metabolic equivalent, or MET.
One MET is equivalent to the energy expended while quietly sitting. Walking slowly, at 2 mph, is the equivalent of about two METs, walking briskly at 3 mph is the equivalent of 3.3 METs and running at 8 mph is the equivalent of 13.5 METs, according to Harvard Medical School. Activities that expend fewer than 3 METs are considered light, activities that expend 3 to 6 METs are considered moderate and activities that expend more than 6 METs are considered vigorous, the researchers wrote.
To determine how running and walking affected heart health, researchers looked at each person's energy expenditure and whether a physician diagnosed them with hypertension, high cholesterol, diabetes and coronary heart disease during the study.
They found that walkers and runners who expended the same amount of energy "have pretty much equal benefits for major heart-disease risk factors," said study researcher Paul T. Williams, a principal investigator at the Lawrence Berkeley National Laboratory in California.
In other words, someone who walked at a moderate pace enjoyed the same reductions in risk as someone who ran at a vigorous pace, provided they both covered the same distance.
The more activity the runners and walkers did, the greater their health benefits, Williams added.
Walking and running are ideally suited to a comparison of the health benefits of moderate- and vigorous-intensity activities because they both use the same muscle groups and involve traveling along a course, but they are performed at different intensities, Williams said.
"This is a valuable study that was done on a large number of people," said Dr. Gerald Fletcher, a cardiologist at the Mayo Clinic in Jacksonville, Fla., and a spokesperson for the American Heart Association (AHA) who was not involved in the study. "It shows that the quantity of exercise you do" is important, he said.
"Physical inactivity is a major modifiable risk factor for heart disease," Fletcher said, adding that walking is the ideal activity for someone who has been sedentary or who is unable to run.
The Centers for Disease Control and Prevention and the AHA recommend that adults spend a minimum of 30 minutes daily, for five days a week, doing moderate-intensity exercise, or at least 20 minutes daily, for three days a week, doing vigorous activity.
It's fine to combine exercises of different intensity ? for instance, walking briskly for 30 minutes twice a week and running for 20 minutes two days that week. The goal is to raise the heart rate, which builds cardiovascular fitness, controls weight and reduces the risk of chronic diseases, according to a 2007 report in the journal Medicine & Science in Sports & Exercise.
The study is published today (April 4) in the journal Arteriosclerosis, Thrombosis and Vascular Biology.
Pass It On: Walking may be just as effective as running in lowering the risk of heart disease.