An article today in the New York Times proclaimed that the recommendation that everyone walk 10,000 steps a day is no longer sufficient. Instead, we now should walk 15,000 steps a day.
Why the change? It is based on a new study of 111 postal workers in Scotland. It turned out those workers who walked the longest routes, over 3 miles a day, had the best metabolic and body mass scores, compared to workers who walked shorter routes or those who had desk jobs.
The flaw, like many studies of this kind, is that the health differences among workers may be influenced by factors that led to selection into jobs that involved different amounts of exercise in the first place. It’s possible that the people who were not in good shape and didn’t like to exercise in the first place took desk jobs or moved to desk jobs because of health issues, while the most hardy postal workers opted for the longest groups. In fairness to the author of the story, Gretchen Reynolds, she did mention the possibility that selection into these different roles influenced the findings
There is no question that exercise is good for us, but claims that certain types or amounts of exercise are better usually are based on small samples or weak inferences from the data, as in the Scottish study. Likewise, the claims that one type of diet or any other magic bullet will prevent aging and disease are overstated. As we saw last year with butter, recommendations that something was bad for us can change. Likewise, we can find that recommendations of a health-promoting food, supplement or type of exercise ultimately prove to be wrong.
For a long time, one of the most prominent theories of aging was that molecules called “free radicals,” which were by-products of metabolism, caused damage to body tissues and could lead to disease and frailty. We were advised to take supplements or eat foods high in anti-oxidants, “superfoods” like blueberries, goji berries or dark chocolate to help bind with free radicals and prevent them from doing any damage.
Now it turns out evidence from animal studies suggest that certain free radicals are associated with longer life, and that lowering levels under some circumstances might be a bad thing to do.
So what should you do?
First, continue to eat dark chocolate. Whatever it may or may not do at a physiological level, it tastes good and makes us happy.
Seriously, the answer is to ignore all the crazy advice. Aging is determined by multiple factors and no one thing is going to prolong life or prevent Alzheimer’s or any other disease.
The best strategies for living to a good old age involve moderation.
· Regular, daily exercise is good. Doing too little or too much is bad. Our joints, feet and back are vulnerable and can wear out with high impact and high intensity exercises. What’s the right amount? Work up to a reasonable amount but don’t do anything that causes pain or discomfort.
· Controlling weight is good. Too much or too little is bad, although the latter does not get enough attention. One of the best ways to control the amount you eat is to eat food that tastes good. It’s satisfying and you don’t then eat too much or feel like snacking. A desert made with real butter and dark chocolate, for example, will taste great and be satisfying in a small amount.
· Cognitive stimulation is also a good thing. You don’t have to buy the computer programs that train cognitive skills. Just challenge yourself to do new things. Don’t fall into a rut. As our long-time friend Margy Gatz said, “Be an interested person.”
· Do things you enjoy. You can do more of the things you like if you are not preoccupied about whether you are eating the right foods or getting the right kinds of exercise or stimulating your brain in some optimal manner.
· And don’t pay too much attention to politics. It’s OK to do things, like call or write your Congressman or Senator, but don’t dwell on the craziness.
These steps do not guarantee a long life free from disease. Nothing does. But these approaches put us on the right track. And they allow us to enjoy each day.
“Should 15,000 Steps a Day Be Our New Exercise Target?”
"The Myth of Antioxidants" Scientific American