I heard a great concept this week: the “health span.” It’s not exactly your lifespan, but rather the length of time you live in good health. So if you live to be 85, but spend the last 10 years of your life in declining health, then your lifespan may have been 85, but your health span was 75. Now let’s apply this concept to populations instead of individuals, because that’s where you see how we can make a real difference.

In the current era of rampant illness in which one-third of current adolescents are expected to become diabetic, we expect the majority of Americans to come down with one or more chronic diseases at least by middle age, say age 50. Carrying a chronic disease markedly increases the likelihood of your having to add another one to your list. That’s why if you have diabetes, the chance that you also take medicine for hypertension or high cholesterol is very high. That’s how it works. And once your medical history includes a list of chronic diseases and corresponding medications, there is a strong chance that you will begin to experience a slow but steady deterioration of your health and well being. And yes, it would be even worse if you didn’t take the medicine, so that’s not a solution.

Now, almost imperceptibly, your world begins to shrink without your even being aware of it. At least at first.

You may be hospitalized for a complication, and spend a long period in recovery. This might make you less mobile or less energetic than you used to be, and you might be unable to dig a new garden, or lay a patio, or visit family, or go on a vacation this year. This might happen a few times. And between each one of these episodes, you might discover, in retrospect, that you never bounced back all the way to where you were at the beginning. This is the difference between a health span and a lifespan.

I’m sure that you’ve had the pleasure of meeting individuals in their 80s, and even occasionally in their 90s, who were sharp and engaging, living independently, enjoying their retirement years, remaining active in the community, participating in a book group, volunteering, taking an exercise class, going to yoga, keeping company with a friend or a spouse, and/or enjoying their great-grandchildren.

I wish not for slow and inexorable declines, but rather for large populations of neighbors enjoying our days all the way to the end. The goal would be to have the health spans  of Americans extend as long as possible, so that they almost match our lifespans. How are we to do this? By protecting our wellness as fiercely and lovingly as is humanly possible.