“Watch over yourselves carefully…” — Deuteronomy 4:15

Vigilance requires a lot of energy. Being alert to the possibility of danger or difficulty can be a full-time job. So can exercising. During the Olympics, we’re all a little more careful about exercise, trying to live up to a gold medal standard. And—with the flair of a cliched bar mitzvah party—during these Olympics, gymnast Aly Raisman propelled the American team to gold, with her floor exercise to “Hava Nagila!”

In the spirit of good health, the author A.J. Jacobs did a two-year experiment that he wrote up as his latest book, “Drop Dead Healthy.” The same man who read through the entire Encyclopedia Britannica and lived biblically for a year committed himself to researching the best way to keep a healthy mind and body. In his words: “I will attempt to have the healthiest heart and healthiest brain. But also the healthiest skin, ears, nose, feet, hands, glands, genitals and lungs.” He set off to speak to doctors and trainers and bought an Areca palm to filter dirty air.

He also devised a makeshift treadmill desk and clocked in over a thousand miles writing the book. He researched juice fasts and the effects of noise pollution. He avoided toxins and ate superfoods and took nutritional supplements. He bought ridiculous exercise clothes and ran barefoot in Central Park, following lots of food and exercise trends. Using the World Health Organization’s definition of health, Jacobs narrowed his goals to 1) Longevity, 2) Freedom from disease and pain, and 3) A sense of emotional, mental, and physical well-being. That’s a lot to accomplish.

Jacobs conducted the kind of experiments we all probably know we should undertake because we act counter to good health all of the time. We don’t exercise as much as we should, and we eat foods that aren’t healthful. Let’s face it; we are all guilty of knowing what we should do when it comes to being healthy yet ignoring advice. All of our rational designs fall apart in front of a cupcake. When it comes to the discipline we need to be our best physical selves, we balk and take a nap (also healthy).

The verse above from Deuteronomy—“u’shmartem me-od le’nafshotechem”—has been used as a divine health warning and is the central verse used against practices like smoking. While it is true that many very committed Jews smoke, virtually every rabbinic authority discusses the fact that it is not permissible to begin smoking on the grounds of this verse given all that we know about the risks involved. Of course, there was a time when smoking was touted as healthy, but today we know too much about lung cancer and other related illnesses to keep our heads in the sand. The fact that observant Jews ignore this prohibition undermines, in so many ways, an even more central Jewish value. We say “to life”—l’chaim—when we make a toast because Jewish survival is predicated on our commitment to long life. Anything we willfully do to curtail our lives transgresses this prohibition.

The chapter that houses this verse uses similar language in another verse. It is not only our bodies that require watchfulness: “But take utmost care and watch yourselves scrupulously, so that you do not forget the things that you saw with your own eyes and so that they do not fade from your mind as long as you live” (Deut. 4:9).

Our minds as well as our bodies require conscious, intentional cultivation so that we remember what we stand for since we have witnessed history being made. We can’t forget these lessons. Vigilance takes many forms.

C.S. Lewis is attributed with saying: “You don’t have a soul. You are a soul. You have a body.” In this formulation, the bodies that keep our souls in trust must be nurtured and well-kept so that the soul can thrive and grow. It takes more than a vegetable juicer and an Areca palm to be healthy. It takes vigilance.

Editor’s note: This article is distributed with permission of Erica Brown. Subscribe to her “Weekly Jewish Wisdom” list at http://leadingwithmeaning.com.