After reading this, you’ll want to stop your hippocampus from shrinking. This part of the brain atrophies with age and plays a major role in learning and memory. For a new study, sedentary older people began a regular, aerobic exercise program—walking for 40 minutes three times a week. After one year, they showed increases in the size of hippocampus and improvements in memory.
Brisk walking and other forms of regular aerobic exercise have long been known to benefit the cardiovascular and upper respiratory systems. (Read “You can be fat and fit”) And epidemiological studies indicate that regular aerobic exercise is associated with improvements in cognitive function.
The new study, however, is the first randomized controlled human trial to show that aerobic exercise can reverse what researchers call “hippocampal volume loss in late adulthood,” and this in turn leads to improvements in spatial memory. Neuroscientists describe spatial memory as the part of memory that is responsible for recording information about one’s environment and its spatial orientation. For example, a person’s spatial memory is required in order to navigate around a familiar city.
This study was conducted by a team of psychologists at several American universities and published online Monday in the Proceedings of the National Academy of Sciences.
All of the 120 study participants, age 60 to 80 years old, were sedentary when they were randomly assigned to either start exercising aerobically or not. The people in the aerobic exercise group were supervised by trainers who started them off slowly with 15-minute walks, ultimately working up to the three times a week 40-minute brisk walks around a track. The people in the control group were taught to do stretching exercises. Memory tests were given and magnetic resonance images (MRIs) were taken of the brain before, mid-way, and at the end of trial.
Here are the results: After one year, the hippocampal volume had increased by 2% in the people doing aerobic exercises; and it decreased by 1.4% in the people in the stretching group. This is a startling result considering that hippocampal volume shrinks 1-2% annually in older adults without dementia, starting around age 60. As for the tests of spatial memory, there were improvements shown in both groups, though more so in the walkers.
Brain researchers have observed that a shrunken hippocampus is associated with impaired memory and an increased risk for dementia. This study shows that you don’t have to exercise very much to improve brain function. Asked for the take-home message of the new study, co-author Kirk I. Erickson, Ph.D., University of Pittsburgh, answered by e-mail, “It is never too late to start exercising. Even those people who have been sedentary all of their life can benefit and improve from an exercise regimen. The brain remains modifiable well into late adulthood and exercise has the capacity to take advantage of this plasticity.”
Maryann Napoli, Center for Medical Consumers©