Merceda Schmidt, a 91-year-old resident of Calgary, Canada, plays piano and volunteer teaches. And she walks nearly 4 miles (6 kilometers) a week.

"It's just in my nature — the batteries I got when I was born," Schmidt says. "My legs want to go."

All that walking apparently helps keep her brain going, too.

Schmidt was one of 42 Calgary women, average age 65, who participated in a new study that adds to a slew of recent findings showing exercise is good for older brain.

One group of the women had been participating in aerobic activity regularly. The other had been sedentary. Researchers recorded and measured the women's cardiovascular health, resting brain blood flow and the reserve capacity of blood vessels in the brain, as well as cognitive functions.

The active group had 10 percent lower blood pressure while resting and when exercising; their vascular responses in the brain during submaximal exercise were 5 percent higher; and did 10 per cent better cognitive function scores.

"Being sedentary is now considered a risk factor for stroke and dementia," said University of Calgary researcher Marc Poulin. "This study proves for the first time that people who are fit have better blood flow to their brain. Our findings also show that better blood flow translates into improved cognition."

The research, supported by several institutions, is detailed in the journal Neurobiology of Aging.

Other recent studies have found exercise help kids with academics, too.

Poulin now has a message for everyone: "Basic fitness — something as simple as getting out for a walk every day — is critical to staying mentally sharp and remaining healthy as we age."

Merceda Schmidt had this to say: "I have to admit, I was nervous before the bike test. I could've done better if my shoe hadn't fallen off."