This is your brain on walking

It’s safe to say that everyone in our club walks during our workouts. For racewalkers and power walkers, it’s a skillful competitive art. Sprinters, middle-distance runners and field-event athletes walk while warming up and cooling down. Those of us on the “injured reserve” put in our laps to maintain fitness and stay in touch with supportive teammates.
 
Most of us, most of the time, take walking for granted. But this humble activity can improve memory, a factor associated with successful aging.
 
Boosting memory
 
Jeremy DeSilva provides proof in First Steps: How Upright Walking Made Us Human. The hippocampus, where memories are stored in the brain, “shrinks at a clip of 1 to 2 percent each year” as we age, he writes, “and it becomes more and more difficult to recall things that used to come to us instantly.”
 
DeSilva describes a study in which University of Pittsburgh psychologists “gathered 120 aging but otherwise healthy folks from the community. They gave them MRIs and measured the size of their hippocampus.” Half of the subjects were asked to walk forty minutes three times a week. The other half – the control group – only did stretches and did not take the long walks.
 
“After a year, the stretching group had lost between 1 and 2 percent of the volume of the hippocampus,” DeSilva says. “That was expected. But something extraordinary happened with the walkers. Not only had they not lost any hippocampal volume. They gained some. The walking group, on average, had grown the hippocampus by 2 percent. Accordingly, their memory had improved.”
 
“Miracle-Gro for your brain”
 
How, exactly, does walking cause such dramatic improvement? “One explanation is that walking, or any exercise, helps get the blood flowing,” according to DeSilva. “But blood is just the vehicle. It must be carrying something of critical importance to the brain.” 
 
DeSilva singles out molecules called myokines as that critical factor. One of them, irisin, has been found at “alarmingly low levels in humans with Alzheimer’s.”
 
Another myokine is BDNF, which stands for brain-derived neurotrophic factor. “The walkers in the University of Pittsburgh study whose hippocampus increased by 2 percent also had higher levels of BDNF than the nonwalking group,” DeSilva says. “John Ratey, a clinical psychiatry professor at Harvard Medical School, calls BDNF ‘Miracle-Gro for your brain.’ ”
 
But wait! There’s more!
 
First Steps also describes how walking can increase creativity and help relieve symptoms of depression and anxiety – two more great reasons to walk regularly. It certainly convinced me to get striding, right this minute. Now if only I could remember where I left my walking shoes…

--Leah Rewolinski