Jan. 31, 2011 -- Staying active as an older adult may keep both the body and the brain in shape.
A new study suggests moderate aerobic exercise may slow or even reverse age-related memory loss in older adults by increasing the size of the hippocampus, a part of the brain that assists in forming memories.
The volume of the hippocampus may shrink and lead to memory impairment in the elderly. But researchers found one year of moderate aerobic exercise, like walking, in a group of older adults increased the volume of hippocampus by 2%, which effectively reversed the age-associated shrinkage by one to two years.
"We think of the atrophy of the hippocampus in later life as almost inevitable," says researcher Kirk Erickson, professor of psychology at the University of Pittsburgh, in a news release. "But we've shown that even moderate exercise for one year can increase the size of that structure. The brain at that stage remains modifiable."
Exercise and the Brain
In the study, published in the Proceedings of the National Academy of Sciences, researchers randomly assigned 120 sedentary adults between the ages of 55 and 80 into one of two groups. One group began an aerobic exercise program of walking around a track for 40 minutes a day, three days a week; a comparison group limited exercise to stretching and toning exercise.
Brain scans taken at the start of the study and again one year later showed that the right and left sides of the hippocampus increased by 2.12% and 1.97%, respectively, in the aerobic exercise group.
In contrast, these regions decreased in volume in the comparison group by 1.40% and 1.43%, respectively.
Tests of spatial memory function also showed improvements in the aerobic exercise group associated with this increase in hippocampus volume.
Researchers say they also found increases in several markers associated with brain health, such as brain-derived neurotropic factor (BDNF) that corresponded with the increase in hippocampus volume.
"The results of our study are particularly interesting in that they suggest that even modest amounts of exercise by sedentary older adults can lead to substantial improvements in memory and brain health," says researcher Art Kramer, director of the Beckman Institute at the University of Illinois, in the release. "Such improvements have important implications for the health of our citizens and the expanding population of older adults worldwide."