A new study backs up earlier research that demonstrated a strong connection between fitness levels and the size of the hippocampus.
Let me explain. The hippocampus, which is located deep within the brain, is responsible for storing and retrieving memories. Unfortunately, like many parts of our bodies, it usually atrophies as we age. That means it shrinks, which can lead to memory loss.
In a previous study, researchers at the University of Pittsburgh and University of Illinois at Urbana-Champaign measured the cardio respiratory fitness of 165 adults between the ages of 59 and 81. Then, using MRI, they analyzed the volume of the hippocampus of each participant and conducted some memory tests. They found that the most physically fit people had a larger hippocampus and the people with a larger hippocampus did better in spatial memory tests. Spatial memory is our ability to record information about our surroundings. For example, imagine yourself in a parking lot filled with cars. It’s your spatial memory that helps you recall what your car looks like and where you parked it.
The latest analysis was led by the same researchers who did the previous study – Kirk Erickson, professor of psychology at the University of Pittsburgh and Art Kramer, director of the Beckman Institute at the University of Illinois. It was just published in Proceedings of the National Academy of Sciences.
They took 120 healthy, but sedentary people between the ages of 55 and 80 and divided them into two groups. Half of them walked 40 minutes a day, three days a week for one year. The others only did stretching and toning exercises.
They did brain scans on the participants before and after the study so they could compare the size of the hippocampus.
At the end of the year, in those who only did the stretching and toning, the hippocampus had shrunk 1.4 percent, which is consistent with normal aging.
The hippocampus did not shrink in the people who walked. Instead, it increased in size by 2 percent. According to the researchers, the size increase amounts to turning back the clock about two years. And what it all means, they say, is that a shrinking hippocampus is not inevitable. The shrinking can be reversed with just moderate exercise.
What isn’t known yet is what happens to the hippocampus when you stop exercising and what benefits there might be for people who exercise more intensely and more often.
But what they know now is good enough for me because I needed a little nudge to be more physically active. I am already keenly aware that walking is good for my heart, my bones, and my disposition – for just about everything, really. Yes, it’s time for a brisk walk. I do think I could manage 40 minutes a day, three days a week. Can you?