If there ever was a reason to “Just Do It”, this is it: Moderate amounts of daily exercise can increase the size of the brain and may reverse some memory loss in older adults. And the best news is that it is never too late to start.
Walking 40 Minutes a Day, Three Times a Week, Increased Brain Volume
A team of researchers from four universities studied 120 adults ages 55 to 80, all which were sedentary but without dementia. The participants were assigned to one of two groups. The first participated in aerobic exercise (walking) for 40 minutes three days per week for one year. The second group did stretching and strength training exercises, such as using dumbbells, resistance bands and yoga.
At the beginning of the study, the researchers used MRI images to assess the volume of the brain’s hippocampus, an area of the forebrain that helps regulate emotion and memory. The size of the hippocampus decreases normally with age (about 1 to 2%), leading to memory impairments. But it is also noted that its rapid atrophy and deterioration precedes Alzheimer’s disease and dementia.
The participants also used a computer task to test memory. All assessments were repeated at 6 months and again after one year.
Those in the aerobic group showed an increase in hippocampal volume by about 2 percent, while the stretching-only group had a decline of 1.4 percent. Those who exercised regularly also improved their performance on the computer test.
The researchers also noted an increase in a molecule called brain-derived neurotrophic factor, or BDNF. This protein acts on certain neurons, helping to support their survival and encourages the growth and differentiation of new neurons and synapses. BDNF is important particularly for long-term memory.
The authors state that exercise is especially useful for improving the rate of “senior moments” such as remembering where you put your keys or remembering the name of someone you just met. This type of memory is called spatial memory.
The benefits of exercise were not limited to the younger participants. “The brain remains modifiable well into late adulthood, and just moderate amounts of exercise takes advantage of this ability,” says senior author Art Kramer from the University of Illinois.
"What's really amazing is that exercise seems to be incredibly powerful and it's not the first thing that comes to mind when we think of exercising our brains. We think of crossword puzzles, sudoku or reading a newspaper. We don't think of going for a walk," said lead author Kirk Erickson, professor of psychology at the University of Pittsburgh.
Erickson KI, et al "Exercise training increases size of hippocampus and improves memory"PNAS 2011; DOI: 10.1073/pnas.1015950108.