The simple habit that makes your brain grow
Here’s a terrifying statistic: The number of Americans with Alzheimer’s disease will increase 40% in the next 12 years, according to a projection from the Alzheimer’s Association. But there’s one simple (free!) measure you take to ward off dementia’s brain-wasting effects: exercise.
“Dementia may not be an inevitable part of aging—in fact, well into late adulthood, the brain has the remarkable ability to continue to grow rather than atrophy,”
says Kirk Erickson, PhD, of the University of Pittsburgh, who presented his brain research findings at the International Conference on Nutrition and the Brain held this summer.
Regular physical activity has been shown to reduce the risk of dementia, including Alzheimer’s disease, by as much as 50%. That’s according to more than a decade of research in the U.S. and abroad, says Dr. Erickson, who published a 2012 review of studies that involved thousands of participants in Archives of Medical Research.How does exercise protect against dementia? The brain’s hippocampus and prefrontal cortex play dominant roles in memory formation and complex thinking, and their deterioration can be a predictor for Alzheimer’s disease. Amazingly, researchers are finding that these are the very areas responsive to physical exercise. In fact, higher fitness levels correlate with an increase in size in both the hippocampus and the prefrontal cortex. This means that exercise can help our brains continue to grow, and thus head off risk of cognitive decline.
Take, for example, a study of 120 sedentary adults in their 60s and 70s, published in Proceedings of the National Academy of Sciences. Dr. Erickson and his team had one group perform aerobic exercises and another group perform stretching exercises for one year. “We saw an increase in brain volume, especially in the hippocampus, in the aerobic group and not in the other group,” he says. “This is evidence that moderate intensity exercise moved participants’ brains in the direction of growth instead of diminishment.” (Looking for a plan you can stick with? Try our Belly Fat–Blasting Walking Workout.)
It’s never too late to start, Dr. Erickson says. “The earlier you begin, the greater the protection for your brain—but exercise leads to improved brain function at any age.”
And you don’t need to work out an hour a day to experience benefits, either. “Roughly 30 to 40 minutes of brisk walking several times a week will improve brain function and cognitive performance,” Dr. Erickson says. Increasing the intensity of your workout could offer additional protection. “Research suggests that moderate intensity exercise is sufficient for improving your brain, but that more vigorous activity might have additional benefits,” Dr. Erickson adds. “Further research is needed to identify the effects from different intensity levels.”