8% More Gray Matter
10,000 steps a-day is a benchmark against which all daily activity has been measured since the 1960s. But this figure was not a product of scientific study. It simply reflected what some experts believed was needed to preserve cardiovascular health. To get a figure grounded in a clinical trial, a large group of researchers from different institutions led by Harvard Medical School decided to find out how many steps a day are required to specifically preserve brain function. They tracked 183 healthy men and women with an average age of 73 – fairly advanced in age. None of the participants had been diagnosed with dementia, but some had elevated levels of the amyloid brain plaques that are linked to cognitive decline and Alzheimer's. (As readers of this publication know, plaques have not been established as the cause of dementia.) The researchers factored in age, gender, education, weight, blood pressure, whether taking blood pressure medication, apoE4 status (the gene that predisposes people to dementia), and smoking habits. All the participants underwent brain scans at the start and finish of the study, plus annual tests of cognition.Save Yourself a Few Steps
After eight years, the more active members of the group retained eight percent more gray matter and experienced less cognitive decline. Neurologist JasmeerChhatwal, one of the study authors, commented, "One of the most striking findings from our study was that greater physical activity not only appeared to have positive effects on slowing cognitive decline, but also on slowing the rate of brain tissue loss over time in normal people who had high levels of amyloid plaque in the brain." Fellow author Reisa Sperling pointed out, "Beneficial effects were seen at even modest levels of physical activity, but were most prominent at around 8,900 steps..." Please note that the optimum amount of exercise for heart health, cancer prevention, and other objectives might be more or less than the results seen in this study. This study only looked at the brain effects. Meanwhile, if 8,900 steps still seems like too much, a second study suggests benefits might come from a fraction of that number.Boosts Connections in Your Hippocampus
Neuroscientists at Oregon Health & Science University set out to discover the brain-specific benefits of single short bouts of exercise. The design of the experiment was to place physically inactive mice on wheels and let them run the human equivalent of 4,000 steps. In doing so, the researchers made a key discovery. A largely ignored gene called Mtss1L was activated by these short bursts of exercise. It promoted dendritic spines -- small growths on neurons -- that increase connections and the transfer of information across brain cells. This was seen in the hippocampus, a key memory and learning center of the brain. The gene is very similar to human genes that prime the brain for learning. Lead researcher Gary Westbrook said, "Exercise is cheap, and you don’t necessarily need a fancy gym membership or have to run 10 miles a day.” Of course, mice aren't humans, so we’re not sure this finding will apply to us, but 4000 steps will take 40 minutes. That's still a good workout for the heart, and what's good for the heart is good for the brain too.Meet
The Expert:
The Expert:
Susan Clark is an award-winning, Emmy-nominated journalist and author who has written about nutrition, health, and wellness for 27 years. She has developed content for articles, reports, books, videos, and television news segments featuring some of today’s top alternative and integrative doctors. She earned a bachelor of science in broadcast journalism from Texas Christian University. She lives in Los Angeles with her husband, two sons, and numerous pets.