Older adults who don't exercise can improve their higher brain functions, such as those needed for driving a car or scheduling events, by doing a little walking, research shows.

The study in today’s Nature is simple in principle but reveals insights into brain function and how to better preserve at least some of it.

The simple part: Walking or any other aerobic exercise appears to get blood pumping to the brain and makes people think more clearly. The more insightful part is that this increased blood flow has a selective effect on the brain, improving functions associated only with the frontal and pre-frontal areas of the cortex, says cognitive neuroscientist Arthur Kramer of the University of Illinois at Urbana-Champaign.

In those areas are the brain cells that fire when people have to think about several things at once, such as planning, scheduling, and looking up a phone number and remembering it long enough to call without writing it down.

Those are examples of “executive control processes,” which among brain functions show the greatest decrease in efficiency with age.

“I think this has fairly important implications on real world mental functioning at older ages,” Kramer says. “The executive control processes are involved in making any new decisions, juggling tasks and learning new skills.”

For the study, Kramer and colleagues took 124 people ages 60 to 75 whose primary activity was sitting around the house. He tested them for their level of aerobic endurance on a treadmill and measured their levels of executive control function with cognitive tests.

Half the group then engaged in yoga type stretching exercises, and the other half started walking three times a week. After six months, the walkers averaged a mile in 16 minutes, a minute faster than at the beginning, and the stretchers had become more flexible.

Both exercise regiments were considered minimal, Kramer says.

When re-tested for higher brain functions after six months, the walkers scored up to 25% higher than the stretchers, enough to make a significant difference in the real world, Kramer says. The aerobic exercise did not make a difference on tasks controlled by other brain areas.

The next question is whether greater amounts of aerobic exercise will improve brain functions even more. Kramer has begun testing older athletes.

Maintaining aerobic fitness throughout life should preserve executive functions. Older athletes should have higher baseline levels than people who are sedentary.