Imagine yourself as a Chevy or VW or Ford or whatever. Your well-being as a car depends on the same four elements as your body 1) design 2) accidents 3) maintenance, and 4) age. I wrote a major paper in the American Journal of Public Health with this title several years ago. The importance of elaborating these values is that each lends itself to quantification, and from there it leads to being able to write a health equation with firm metrics. Adopting the quantitative assessment of health and its determinants leads in turn to individual behavior choices and to a remedial strategy for a dysfunctional health care system.
Let's work our way through the argument.
Clearly, if your car (body) is not well designed it will likely not get off the showroom floor. Lemons aren't very popular. Fortunately the number of human lemons is very small. Less than 2 percent of human newborns have a defect. Mother Nature is a very caring obstetrician, insuring that almost all the defective fetuses are aborted in utero.
Also if design were very determinative of health then twins, being identical, would die simultaneously of the same thing. They don't. Numerous large surveys reveal that something in the range of 15 percent of subsequent health encounters (longevity most importantly) are design dependent. It is then appropriate to conclude that "it's not the cards you're dealt that matters it is how you play the hand."
The second major of the health determinants is accidents. Clearly if your car insists on running into things or being run into by others its health quotient is problematic. Your car or your body will be spending a lot of time in the repair shop. What I mean by accidents are those misadventures that are not your personal choosing, among these are most infections, poisonings, starvation, wars, and malignancy. It is important to note however that many of these are preventable with good self-care.
The third determining agency is maintenance, and like a car that is useful, fuel and RPMs are critical. If inappropriate fuel or if too much or too little goes into your body it malfunctions.
This fuel component is rampant. Obesity is epidemic.
So, if you run your car too hard or not hard enough it will cost you money. Too many RPMs to your body as stress will wear you out before your time. Also too few RPMs spent on the couch or before your screen will shorten your days on earth. Disuse is a major pathology. I have written extensively on this issue. We inevitably know the pervasive value of a physically active lifestyle.
Finally, the fourth determinant is aging. Your car and your body inevitably show the signs of wear and tear. We are fortunate that this component is rather graceful in its decay slope (around 0.5 percent per year). The exponential attributable to aging per se is very much obscured by disuse. Most of the change that is casually attributed to aging is in reality due to disuse. This differentiation is critical because of the precepts of the Serenity Prayer. Change what you can. Accept what you must BUT, know the difference. Of these four determinants of health two are changeable, maintenance and accidents whereas the other two are immutable, design (heredity), and aging. Such recognition is mandated if meaningful change is expected.
Now you are an expert in health determinants.
Live abundantly, but wisely according to these dictates.