Ask the Doctors

Dear Doctor: I've been an avid runner since high school, but I'm turning 65 this summer and my wife and my kids have been after me to switch to walking. I think I remember hearing about some study that said running actually makes you younger. If so, can you help with a recap? I need some good arguments for our next family gathering.

Dear Reader: Congratulations on your birthday, and for sticking to an exercise regimen over the decades. You haven't mentioned any injuries or other physical difficulties as a result of your running, so we'll assume you're simply dealing with the typical issues that come with aging.

We did a bit of research and found the study you're referring to. It was conducted by teams of researchers from the University of Colorado in Boulder and Humboldt State in Arcata, California, and was published in 2014 in the journal PLOS One. The takeaway of the study was that running may slow or even reverse certain aspects of the aging process in ways that walking for exercise does not.

Decades of research show that as people age, their "walking economy" declines. That is, despite expending increasingly more energy, the rate at which older adults walk grows progressively slower and less efficient. Since walking performance is tied to a variety of important health indicators in older adults, this slowdown has become a focus of research. In this particular study, scientists evaluated the walking performance of 30 women and men whose ages ranged from mid-60s to early 70s. Half regularly walked for at least 30 minutes at a time, three times per week. The other half also exercised three times a week for 30 minutes at a stretch, but at a brisker pace -- at least a jog.

After being evaluated on specialized equipment to measure energy output and oxygen usage, it turned out that the runners were the most efficient at walking. Even more surprising, their energy usage was comparable to that of a sedentary 20-year-old. The walking group, meanwhile, did not perform any better than people their own age who did not exercise. Bottom line, according to the researchers, is that the physiological effects of running slowed certain aspects of the aging process.

Lest any of you non-running readers decide to ditch exercise altogether (please don't!), it's important to note that walking still offers multiple important health benefits. These include improved cardiovascular health, improved mood, better weight control and a lower incidence of diabetes. What walking doesn't appear to do, according to this study anyway, is head off the age-associated dip in kinesthetic efficiency. Although the reason why isn't entirely clear, researchers suspect that running has a positive effect on muscle physiology and energy production, which take place at a cellular level.

One final note about running, which may make your wife and kids happy. Another study from the University of Iowa found that running at a slow pace for as little as five to 10 minutes at a time measurably reduced all-cause and cardiovascular mortality risk.

We hope this helps with your next dinner table conversation.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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