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HealthDay News -- Walking for exercise achieves the same health benefits as running, although more walking is necessary to get the same results, researchers found.
Expending the same amount of energy in either activity yielded similar reductions in risk for high BP, high cholesterol, diabetes and coronary heart disease, Paul T. Williams, PhD, of the Lawrence Berkeley National Laboratory in California, and Paul D. Thompson, MD, of Hartford Hospital in Connecticut, reported in Arteriosclerosis, Thrombosis, and Vascular Biology.
However, runners usually expend about twice as much energy as walkers, which translates into greater health benefits, results from an analysis of two large cohorts show.
“The more the runners ran and the walkers walked, the better off they were in health benefits. If the amount of energy expended was the same between the two groups, then the health benefits were comparable,” Williams said in a press release.
Although walking may be a more sustainable exercise for some people, "those who choose running end up exercising twice as much as those that choose walking. This is probably because they can do twice as much in an hour,” he added.
Although walking and running use the same muscle groups and motions, the intensity of the activity -- as measured by "metabolic equivalents" or METs -- differs. Moderate intensity exercise is defined as an that activity uses three to six times the oxygen needed to sit at rest, or 3.5 ml of oxygen per kg of body weight per minute (1 MET).
In terms of METs, walking is considered a moderate intensity activity, whereas running, which expends 6 or more METs, is considered vigorous.
To determine whether equivalent doses of moderate and vigorous physical activity have the same health benefits over time, Thompson and Williams compared data from two studies: the National Runners' Health Study II and the National Walkers' Health Study.
They assessed reported exercise, energy expenditure measured in MET-hours per day and incident hypertension, hypercholesterolemia, diabetes and coronary heart disease, in both cohorts. After excluding participants with a previous history of these conditions, the study population consisted of 15,945 walkers (21% men) and 33,060 runners (51.4% men).
During 6.2 years of follow-up, there were 3,874 cases of incident hypertension, 6,637 cases of high cholesterol, 647 new cases of diabetes and 530 cases of coronary heart disease. On average, men and women who ran expended an average 5.29 and 4.74 MET-hours per day, respectively. In contrast, men and women who walked expended an average 2.2 and 2.13 MET-hours per day, respectively.
This difference in average energy expenditure translated into lower health risks for runners vs. walkers -- specifically, a 38% lower risk for hypertension, a 36% lower risk for hypercholesterolemia and a 71% lower risk for diabetes.
However, when energy expenditure was equivalent among runners and walkers, this disparity in risk reduction disappeared. When the MET-hour per day was the same, health risks decreased as follows:
- Incident hypertension risk decreased 4.2% with running and 7.2% with walking (P<10−7)
- Hypercholesterolemia risk decreased 4.3% with running (P<10−14) and 7% with walking (P<10−8)
- Diabetes risk decreased 12.1% with running (P<10−5) and 12.3% with walking (P<10−4)
- Coronary heart disease decreased 4.5% with running (P=0.05) and 9.3% with walking (P=0.01)
For running versus walking, the risk reductions were not significantly different for diabetes (P=0.94) or coronary heart disease (P=0.26). For hypercholesterolemia, the risk reduction was marginally but significantly increased for walking versus running (P=0.04).
"Our results suggest similar benefit for similar energy expenditures," Williams and Thompson wrote. "These results should be used to encourage physical activity in general, regardless of its intensity."