Op-Ed: Diana Nyad on aging: Why 66 is better than 28

I was 64 when I became the first to swim the 110.86 miles from Cuba to Florida, something I failed at when I was 28. The truth is, I am a better athlete in my mid-60s than I was, even as a world champion, in my mid-20s.

The cliche is that we reach our prime in middle age because we are mature; we have found patience and perspective. We recognize that our time is more and more valuable with each fleeting year. We tap into a well of experience and open-mindedness.

All of this is true, but I also believe we can retain our physical vitality into our middle and even older years.

There is no doubt that I am breathing the life force of my prime physical self now, at age 66. I am more resilient. My immune system is a stronger fortress. I can summon a brute strength I never had back in the day. I was a thoroughbred then, more finely tuned but also somewhat fragile. These days I’m more of a Clydesdale, sturdy and stalwart. If you told me I’d be left stranded in the wilderness for many months and could choose at which age I would attempt to survive the ordeal, I’d pick this very age, 66.

Yes, this is a one-way journey we’re all traveling, and it has an endpoint. We have to get real. I can’t pretend I’m not a whole lot closer to the end than ever before. I accept the lines on the face, cartilage thinning in the knees, the breasts riding lower and lower.

What I rail against is the blanket limitations put on us by … whom? Who has done the irrefutable calculations that say we’re too old to work in our professions? Who decrees the assigned ages for productivity and creativity and vitality? I accept the laws of the universe when it comes to aging, but I point-blank refuse to cower in the face of weak and faulty statistics, geared for the masses, that pay little respect to the will and potential of the individual.

I was recently chatting with a couple. The husband happened to mention that he was 54. His wife corrected him to say he was really 55, as his birthday was coming up in two days. He was adamant, all kidding aside: At that moment, he was still 54.

The ultimate irony is that the people most freaked out by the numbers, the wrinkles, the widening of the midsection, waste more of their precious time denying aging than in pursuit of living hard. Think of all the minutes we’ll never get back, the minutes we spent arguing with some stranger that we were not yet 55 but had two more days to go at 54.

This is the crux of it all: We rabidly pursue youth in the name of appearing young. Too many of us aren’t exercising our bodies and carefully contemplating every morsel we put into our mouths so that we can retain our youthful dynamism. We think our value lies in what age we are perceived to be rather than in empirical measurements of how we’re performing and what we’re experiencing.

We baby boomers are lucky. The concepts of middle age and old age are sliding upward. We are feeling feisty at 50 and 60 and 70. At a recent White House Conference on Aging, the central theme was the vast overhaul of assisted-living and nursing home models. The next group moving toward old age is teeming with fierce independence. We are going to radically redefine the golden years.

These days we can reinvent ourselves. We can embrace our “second acts” and be more successful, more spirited, more equipped in all ways, big and small, than we were the first time around. The machine of our youth society dictates that our talents are fading, even our thinking is passe, but ironically it’s that very youth-driven tech culture that can provide us with more avenues of creativity and entrepreneurship than ever before. Trust me, I know we can still dream.

They say age is a state of mind. Age is, of course, a state of body as well. It is up to each of us to live bold, vital days, free from subjugation to the mass, limited interpretations of our respective ages.

What defines my age — my strengths and weaknesses — I insist be left to my own reckoning.

Diana Nyad’s memoir “Find a Way” was published Tuesday.

Follow the Opinion section on Twitter @latimesopinion and Facebook