Do Miles Really Matter?

In their 1975 research article[1], Thomas J. Bassler, MD and Frank P. Cardello, MD concluded that the more active you are, the greater the health benefits. They said, “We advocate the vigorous exercise and … life-style of the marathon runner for everyone, because immunity to coronary heart disease appears to coexist with the ability to cover 42 km (26 miles) on foot.” Dr. Bassler explained, “There is no evidence that speed protects, but mileage does.” In essence, according to their research, mileage provides the best protection against disease.

HOWEVER, later research by exercise physiologist Michael Pollock, PhD, showed a dose-response relationship between exercise and health benefits: The more you exercise up to a certain point, the better you score on such health indicators as heart rate, cholesterol levels and weight. Dr. Pollock’s research made no reference to distance or mileage whatsoever.[2]

So should a runner ignore mileage? According to cardiologist, Dr. George Sheehan, yes. As a member of the Presidential Council for Physical Fitness and an avid runner, he advocated the formula of frequency, time, and intensity. He explained that previous research indicated the frequency of injuries rapidly increased once a runner reaches 40 miles a week. He hypothesized that all runners “take 5,000 strides on each foot per hour. So the critical factor in injuries is time, and injuries begin at 4 hours of training per week, not 40 miles -- “Measuring runs in miles instead of minutes is a big mistake.”[3]

Finally, Dr. Sheehan said, “ … it’s the effort that counts.” Shifting the focus from miles to minutes is especially important for aging runners. We know we are not going to run faster, nor are we going to run consistently farther. It takes more time to run a shorter distance than years past. The 5 mile run now takes just as long as the 6 mile run did a few years ago. But we are still expending the same amount of energy for the same length of time.

It doesn’t matter how far or how fast you run. It only matters that you run.  Effort matters more than miles.

“We run ... because we enjoy it 

and cannot help ourselves.” Sir Roger Bannister 

[1] Jogging and Health, (JAMA. 1975; 231(1):23)
[2] ACSM Position Stand: The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults. Medicine & Science in Sports & Exercise. 30. 975-991. 10.1097/00005768-199806000-00032, 1998.
[3] The Essential Sheehan: a Life Time of Running Wisdom from the Legendary Dr. George Sheehan. Rodale Books, 2013.