Three times a week, 80-year-old Sue Lewis puts on her tennis shoes and goes for a brisk walk around her neighborhood running track. But she doesn't just walk around it once or twice. Ten laps doesn't stop her -- and after 15 laps, you can bet she's still moving. In fact, Lewis has been known to walk around the track as many as 46 times a day. "I walk pretty fast. My cousin has a hard time keeping up with me," she says.
Is there such a thing as a longevity diet? Increasingly, studies suggest the answer is yes.
Around the world, certain groups of people enjoy exceptionally long lives. Consider the lucky people of Okinawa. These Pacific Islanders have an average life expectancy of more than 81 years, compared to 78 in the United States and a worldwide average of just 67. Closer to home, members of the Seventh Day Adventists, who typically eat vegetarian diets, outlive their neighbors by four to seven years on average...
If she's not on the track, you might find Lewis on the treadmill or walking up mountains and across the grass at her family farm in Georgia. Her "keep on moving" motto isn't just keeping her body in great shape, however. Researchers say her brain gets a workout too. Last spring, investigators from the University of California, San Francisco (UCSF), told a conference of nerve specialists that walking may help older women keep their brains young.
"Women who walk regularly are less likely to experience the memory loss and other declines in mental function that can come with aging," explains study author and neurologist Kristine Yaffe, MD.
Indeed, Lewis is as sharp as she is quick on her feet.
"My memory is great," she says. "I'm sharp as a tack, even though I do forget where I put my glasses from time to time."
Flexing Your Mental Muscle
For the study, UCSF researchers tested the thinking power of about 6,000 women aged 65 and older. The women were given a mental exam at the start of the study and then again six to eight years later.
Yaffe and her colleagues found that the women who walked the least -- less than a half-mile a week -- were the most likely to develop mental decline. Nearly a fourth showed significant declines in their test scores, compared to only 17% of women in the most active group.
"It doesn't seem like a big difference, but it really is," says Yaffe.
Physical activity was charted by measuring the number of blocks the women walked per week and also by the total calories they burned in recreation, walking, and climbing stairs. The most active women walked about 18 miles a week, or 2.5 miles a day.
If 18 miles a week classifies you as physically active, then 77-year-old Lura Roehl just might be superwoman. The Washington, DC, native walks three times a day, every day, with her 80-year-old husband, Charles. Together they clock 46 miles a week.