By Robert L. Cain, Copyright 2021
He meant well but had drunk the Kool-Aid. The doctor told me that I should get at least 30 minutes of exercise a day to ensure I would keep a relatively strong core. My response was that if that was all I got, I could well go backwards because I got more than that already. I didn’t find out about his Kool-Aid sipping until after I started writing the Book of Walking.
I discovered more Kool-Aid as I researched the various chapters for the book. I learned that most of the advice we get about exercise, walking in particular, are just made up numbers. I could find no scientific basis for any of it. Even so, it all has become mantra, the big lie. Those who advise about exercise repeat so often that these numbers, all this advice, all these recommendations, have become “fact.”
The advice always implies that we should go big or stay home when nothing could be further from the truth. Keep track of all our walks they say, steps, distance, heart rate, weight loss or gain, and anything else that allows us to examine how well we are doing with our exercise. Most important, pay attention to their dicta. Socrates is credited with saying right before his execution for corrupting the youth of Athens that “the unexamined life is not worth living.” I would reverse that about walking: the unexamined walk is well worth taking. But unexamined data are not worth believing.
Let’s look at a couple of these recommendations that dictate examining every walk. First, the 30 minutes a day, five days a week mantra. As I was writing The Book of Walking, I went looking for the study that showed that was the magic number. I literally spent months trying to track down the proof. I never did find the study, but I eventually did find its first mention. It’s in the 1991 report by the Centers for Disease Control, Healthy People 2000 on page 73 (look it up if you don’t believe me). It states without citing any evidence that 30 minutes a day, five days a week is the magic amount of exercise.
No evidence, no studies, just unproven recommendation. Yet we see that “magic” number repeated over and over again. We start to believe it. We also believe that if we don’t get those 30 minutes a day in, we are doomed to slugdom, should feel guilty about our slugdom, and so we should maybe just give up going for walks lest we are overcome with guilt.
Then there’s the 10,000 steps mantra. That was made up out of whole cloth by a Japanese company before the 1964 Tokyo Olympics. One Dr. Yoshiro Hatano began selling a 10,000 step pedometer known as “manpo-kei” (translation: 10,000 steps meter). He had found that the average Japanese walked 3,500 to 5,000 steps a day. He calculated that if someone walked 10,000 steps a day, it could burn up 20 percent of a person’s daily calories. Well maybe, but that reasoning is circular because the evidence is “proved” by the conclusion. The magic number was to sell pedometers. But so what? If the goal is just better health, that’s one thing. If it’s to lose weight, it doesn’t come close to losing a pound.
Later he admitted the entire notion was just a marketing ploy. Ten thousand steps is a nice round number and easy to remember. Now it has become gospel.
The facts arising from actual research are different. One study conducted by the UCLA Semel Institute for Neuroscience and Human Behavior found that 4,000 steps is enough to help brain health, for example. Those findings were published in the Journal of Alzheimer’s Disease. Each member of the study group had complained of memory problems at the beginning of the study.
The researchers did an MRI to determine the thickness of the hippocampus, the room in the brain where memory is stored. Hippocampus thickness is a predictor of how effective memory will be. The study found that people who walked 4,000 steps a day had thicker hippocampi and related brain regions than did those who walked fewer steps. I don’t know why the study used the cutoff of 4,000 steps. Would 3,500 have been just about as effective? Maybe 5,000 would have done an even better job. The researchers have yet to do a longitudinal study to find out if walking 4,000-plus steps a day continues to keep memory intact. And 10,000 steps is an admitted complete fabrication.
Blood flow to the brain is the determining factor. A study conducted by New Mexico Highlands University mostly “concentrated on running’s effects on carotid artery blood flow as a result of heel impact.” They found that foot strike exercise—both walking and running—pushes more blood to the brain and that helps our brains work better. Dr. Ernest Greene, first author of the study, said, “What is surprising is that it took so long for us to finally measure these obvious hydraulic effects on cerebral blood flow. There is an optimizing rhythm between brain blood flow and ambulating.” All that was needed was blood getting to the brain better. It doesn’t take 10,000 steps to do that.
What’s wrong with just going for a walk and taking pleasure in it? Even if it’s just 15 minutes or only 2,000 steps? We can miss the pleasures of a walk if exercise goals overshadow the enjoyment of the walk itself. If you let Fitbit rule your walks, if you obsess about getting those 30 minutes in or those 10,000 steps, it blows away the pleasures of walking, seeing the sights, breathing the fresh air, stopping to look at a beautiful sunrise or sunset, enjoying the company of a good friend.
There are no magic numbers for walking or exercise. it depends on the individual’s condition and motivation. Walk as much or little as is comfortable, no Kool-Aid drinking, and enjoy the walk.