Don't take age-related declines in brain function lying down.
Get up and exercise.

Aerobic workouts can improve high-level brain functions in the over-50 crowd, say researchers at Duke University.

The findings are an offshoot of a 1999 study at Duke that demonstrated that aerobic exercise was as effective as medication in treating major depression. Participants were a group of clinically depressed middle-age and elderly people.

The same exercise program not only helped lift the depression, but also improved the participants' memories as well as their abilities to plan, organize and juggle different intellectual tasks, the researchers say.

Exercise had a "beneficial effect in specific areas of cognitive function that are rooted in the frontal and pre-frontal regions of the brain," said lead researcher James Blumenthal, a psychology professor at Duke. And, those improvements were above and beyond what the team would have expected once the depression had lifted, he says.

The original study followed a group of 156 people between 50 and 77 years of age who had been diagnosed with major depressive disorder.

Split into three groups, one used medication, one used exercise and the other used a combination of the two. To determine the role exercise may play in cognitive function, the researchers compared the 42 participants in the exercise group with the 42 in the medication group.

The exercise regimen included riding a stationary bike, walking or jogging 30 minutes a day, three times a week for 16 weeks. At the beginning and end of the study, participants took tests to measure depression and others to measure memory, attention and concentration, psychomotor speed and what's known as executive brain functions: planning, organizing and juggling tasks.

Those in the exercise group showed improved executive brain functions, the study says. Findings appeared in the Journal of Aging and Physical Activity.

Better flow of oxygen-rich blood to specific regions of the brain might be responsible for the improvements, Blumenthal speculated, but he says more research is necessary to be sure.

The team is beginning further testing to determine why exercise aided the brain functions of the mildly depressed more than those with severe depression.

"We [also] hope to tease out the effects of exercise from social support by comparing home-based exercise to supervised group exercise," Blumenthal said.

"We will examine other cardiovascular functions that may be associated with depression and modifiable with exercise training." The team also will analyze whether various types of depression respond differently to treatment. Blumenthal said he's optimistic that exercising may be found to help slow the brain's aging process.

There is evidence that those functions, both mental and physical, that are associated with declines with advancing age may be affected by exercise," he said. "

I don't think we're at the stage of our knowledge at this point to have physicians write a prescription for exercise in the same way they might prescribe an antidepressant," he said. "But we may be moving that way."