The reviewers found that even with such skimpy mileage, runners generally weighed less and had a lower risk of obesity than people who jogged fewer than five miles per week or (more commonly) not at all. These runners also were less likely to experience high blood pressure, cholesterol problems, diabetes, strokes, certain cancers and arthritis than the barely- or nonrunners.
“It seems like the maximum benefits of running occur at quite low doses,” said Dr. Carl J. Lavie, medical director of cardiac rehabilitation and prevention at the Ochsner Medical Center in New Orleans and lead author of the review, which was published in September in Mayo Clinic Proceedings.
As little as “one to two runs per week, or three to six miles per week, and well less than an hour per week” can be quite beneficial, he said.
Running a few additional miles each week could be worthwhile if you were worried about middle-aged spread, he said, because additional mileage is generally associated with better weight control, “and allows one to eat more calories.”
Someone hoping to become a better, faster runner also would need to run more than five or six miles a week, he said.
However, there may be an upper limit to the desirable mileage if your primary goal is improved health. Some evidence, he said, suggested that running strenuously for more than about an hour every day could slightly increase someone’s risks for heart problems, as well as for running-related injuries and disabilities.
Over all, Dr. Lavie says, the best advice based on the latest science is that for most of us, “running for 20 to 30 minutes, or about a mile-and-a-half to three miles, twice per week would appear to be perfect.”
New York Times