EXERCISE & YOUR BRAIN

12.12.14 6:00 PM ET

Running 15 Miles a Week Could Slash Alzheimer’s Risk

A new study from the Journal of Alzheimer’s Disease might offer the best reason yet to lace up your shoes and grind out some serious miles.

By Amanda Woerner for Life by DailyBurn

Running has plenty of benefits: It revs your metabolism, helps you build stamina and offers a solid excuse to spend money on killer sneaks. But this new study from the Journal of Alzheimer’s Disease might offer the best reason yet to lace up your shoes and grind out some serious miles. Among 153,000 participants in the National Runners’ and Walkers’ Health Studies, those who ran at least 15.3 miles per week experienced a 40 percent reduction in Alzheimer’s mortality. Yet, logging fewer miles decreased that benefit: Those who ran 4.5 to 7.7 miles per week only saw a 6 percent reduction. Score one for the endurance kings and queens?

Study author Dr. Paul T. Williams, of the Lawrence Berkeley National Laboratory, says this research shows that exercise — and lots of it — might be your best Rx when it comes to preventing Alzheimer’s. “I think this and other research suggest that there are lifestyle choices people can make that will significantly impact their risk for Alzheimer’s disease,” he says.

But is running your best bet when it comes to preventing the onset of Alzheimer’s? And how much do you need to sweat to stave off the disease that kills 500,000 people every year?

Why Exercise Works Your Body and Your Brain

It’s not completely clear why physical activity has such a strong impact on brain health. “But it’s been known for a while that among people who are intellectually more active, or have more intellectually demanding jobs, the onset of Alzheimer’s disease is delayed,” Williams says. “And that’s the same thing that’s going on with exercise.”

As you age, your brain changes. You lose connectivity between portions of your brain, and some regions even experience shrinkage, according to Williams. “That’s prevented by exercise,” Williams says. “And these results don’t just apply to Alzheimer’s, but to general cognition as well.”

Alzheimer’s is a mysterious disease — most doctors don’t know much about how to treat it and there are no effective drugs to prevent it. But Williams believes that by making adjustments to diet and exercise, people at high risk for Alzheimer’s could help delay the onset of disease. “You don’t have to wait for a drug to appear on the horizon,” Williams says. “There seem to be lifestyle benefits that can help.”

Other findings in his study showed that eating three servings of fruit per day can help cut Alzheimer’s mortality risk by up to 60 percent — and previous research has heralded the benefits of the Mediterranean diet for brain health.

Your Running Rx: How Much Is Enough?

While 15 miles per week has benefits, “the sweet spot is probably around 30 miles of running per week,” Williams argues. “If one really wants to go for optimal health the answer is the more the better.”

The good news is that it doesn’t matter how you split up your running schedule to hit your 15-plus mile per week goals — whether you’d prefer to run three days a week, or six, all that matters is your overall miles.

Of course, proper training and slowly building up your miles is key to preventing injury. And walkers benefited from hitting the streets, too. The only catch was that they had to exercise for about twice as long, walking nearly 50 percent further to see the same decrease in Alzheimer’s mortality risk. “Running is just that much more efficient in expending more calories in a shorter amount of time,” Williams says. Other research has shown that strength training also keeps your brain sharp — so don’t be afraid to mix up your workouts by spending time in the weight room, too.

If you’re already logging 15 to 30 miles per week, you’re ahead of the game. The National Runners’ and Walkers’ Health Studies also linked the healthy habit to a reduced risk of eye disease, a variety of cancers, heart disease and stroke in addition to Alzheimer’s. And if you need an extra push to get you out the door, remember: “There’s almost nothing you can do that’s more effective in preventing disease than exercise,” Williams says.