By LIZ TAYLOR

Special to the Sounder

After four decades working in the aging field, I’ve discovered something interesting: we each get “old” at our own unique pace.  This is different from any other time in our lives.

Most 1-year old babies are similar to every 1-year old baby – in size, shape, behavior, cognitive function and so forth. The same is true for 5-year-olds.  And teenagers.  For people in their 20s, 30s, 40s and 50s, too – until some time in our mid-to late-50s. That’s when our appearance, health and capabilities begin to go down different paths.

You’ve heard that 70 is the new 60? Well, 60 can be the new 90 – if we have no muscle tone or stamina. As a society, we’re living longer and healthier than at any time in history. The average life span in America is now 78 (it was 47 in 1900).

But age is fast becoming a relatively meaningless number. Witness the dozens of amazingly spunky people in their 80s and 90s living here on our rock. What’s far more important is not how many years we’ve lived but our liveliness – our health, our ability to live independently, our zest for life.

And that’s where the rubber meets the road. Everyone wants to live a long time, but no one wants to get old. Or, well, if they have to get, ahem, old, they want to be healthy.  Yet few do what they need to do to stay as healthy and vital as they can, which is, as we well know, that dreaded “E” word: exercise.

The one common denominator of healthy aging that science has proven year after year is getting our bodies to move.  It doesn’t have to be vigorous. You don’t have to sweat or breathe heavily. Just getting the engines warmed up, heart pumping, muscles moving, oxygen flowing to the brain for 10 minutes (or an hour) each day helps. It helps us maintain our balance, do the laundry, carry groceries, hoist the grandkids on our knee, take the boat out – even into our 80s and 90s. The more we do, the better.

And exercise won’t stop chronic diseases like Alzheimer’s, Parkinson’s or arthritis, but it helps us live more independently while we have them.

Some lucky few love to exercise. Not me. I’ve disliked it my whole life, but I force myself to do it daily. Now, at the beginning of a new year, it’s time to resolve for you to live more healthfully by exercising, even just a little, and then a little more. The improvements to your spirit and health are incremental but vital. And enduring.