These five tiny monosyllables, 13 letters, might seem inconsequential at first. But reflection indicates that their intent conveys profound cosmic significance. At their root, they represent how an organism, any organism, you and me, relate to the environment, and vice versa.
I have grappled this idiom onto my interest in aging. It all began 50 years ago when I pulled my Achilles tendon while skiing. My right leg was in a cast for six weeks. It emerged old. This prompted my writing a paper for the Journal of the American Medical Association in 1982, called "Disuse and Aging". (1)
It addressed the question as to why my leg became precociously old by being in a cast. There was nothing in the medical literature that explored this reality. It wasn't genes or disease. I pondered. Why did my leg grow old so fast? This then prompted a lifetime inquiry into this phenomenon that has led to the profound conclusion that physical fitness represents a 30-year age offset. Said in another way a fit person of 83, me, is biologically similar to an unfit person of 53. BIG!
At the conclusion of a seminar that I delivered at Harvard a few years ago, an attendee remarked, "If who you are is what you do, when you don't, you aren't." This is a wonderful summary statement.
Further, I am a student of the Serenity Prayer, which basically preaches "Change what you can, accept what you must, but know the difference." You can't change aging. It is the inevitable tax paid for being alive. But you can change fitness. Big insight.
The fitness/ frailty scale is explicitly regulated by being fit. Frailty is the common pathology seen in most older persons, not because they are old, but because they have lost their physical vitality along the way. Fitness is cheap, safe, universally effective and available. What drug can make these claims?
And don't ever forget Bortz's Law: It is never too late to start, but it is always too soon to stop.
Bortz, W. Disuse and Aging 1982 JAMA; 248:1203-1209.