Exercise can help memory

Adding even a small amount of exercise to a person's daily routine can reduce the risk of developing Alzheimer's disease, according to a study published in Wednesday's Journal of the American Medical Association.

The study, by Australian researchers, showed that six months of physical activity -- averaging about 20 minutes a day -- in volunteers 50 and older modestly improved memory and cognition.

"This is the first time anybody has shown that a modest exercise program seemed to slow the rate of Alzheimer's disease," said Dr. Eric Larson, executive director of the Seattle-based Group Health Center for Health Studies, who wrote an editorial accompanying the study.

"In the United States, pharmaceutical direct-to-consumer advertising has sensitized patients and the public to using cholinesterase inhibitors for Alzheimer's disease," Larson wrote. "This illustrates the appeal of 'doing something -- anything' that might help prevent a dreaded disease, even if its value is minimal. Promoting habitual exercise for aging patients seems more worthy."

The researchers randomly engaged 170 volunteers in 24 weeks of physical activity, including walking and swimming, and compared them with a similar group that didn't exercise. The volunteers all reported having memory problems, but none suffered from dementia. They each wore a pedometer and kept a diary of their physical activity.

Participants were asked to perform at least 150 minutes of moderate-intensity physical activity per week, which participants were asked to complete in three 50-minute sessions. They averaged 142 extra minutes of exercise.

Researchers used an 11-test Alzheimer's scale to assess memory, language and skill application over 18 months. Scores range from zero to 70 -- the higher the number the more severe the impairment.

By the end of the study, participants in the exercise group had better scores and less delayed recall. The exercisers also had lower dementia scores.

The study showed an average improvement of 1.3 points on the Alzheimer's scale after six months of enhanced exercise, and 0.69 points after 18 months. That's a tiny boost, researchers admit, but "potentially important when one considers the small amount of physical activity undertaken by participants of the study."

The results are encouraging, said Nancy Dapper, executive director of the Alzheimer's Association's Western and Central Washington chapter.

"With Alzheimer's we don't often have a lot to turn to, and with this study, the amount of exercise is manageable for most people," she said. "The studies are building on each other about the benefits of exercise to the brain.

"The next question might be: Is it worthy to do more studies looking at more vigorous exercise or different types of exercise?"

Researchers don't yet know why exercise makes a difference, but the added benefits can go beyond brain improvements.

Larson said one explanation could be that exercise improves blood flow to the brain. That allows people to better handle the stress that can damage parts of the brain.

"If you ask doctors what disease they fear the most, it's Alzheimer's," said Larson, who writes exercise prescriptions for some of his patients to prod them into getting needed workouts.

"This is a potential motivator to our society to design more walkable and bikeable communities," he said of the study. "It gives people yet another reason to exercise."