The envelope came late, a month after the big day. Somehow I thought I had eluded their gaze. But four days ago, when I got home from work, there it was, sitting on the dining room table, waiting for me.

“AARP,” the return address said. “Membership Certificate and Temporary Membership Card Enclosed.”

Busted.

I turned 50 in December. Friends who preceded me to that milestone had spoken of the day when the letter from the AARP arrived in the mail. They likened it to an unwelcome summons, a computer-generated siren song to a new life stage. In fact, in most cases, the letter preceded the actual event, like one of those early birthday cards

from an obsessive relative.

I guess AARP wants me to retire.

Well, I don’t want to.

I imagine a desert, full of wandering, barrel-bellied men in funny

hats, plaid Bermudas, black knee-length socks and women wearing clothes the color of a sherbet rainbow. I don’t want to retire. I don’t want to be old. Or maybe what I don’t want is to be considered old. My mother, who turned 82 this year, says she looks in the mirror and wonders, “Who is that old woman?”

I don’t want to open their letter. I don’t want to find out about

all the discounts I can get. Fifty-cent coffee. Cheaper seats on planes. Senior discounts at movies. Call it denial. I thought retirement came at 65, so why is AARP after me?

I’m not going to open it. There’s a shredder at work I’ve never used. My wife thinks I’m being infantile. Given the circumstances, that could be viewed as a compliment.

I wonder why the notion of retirement bothers me. After all,

enjoying a hard-earned rest is a reasonable idea. I think of my old friend Joe Zingarelli, who spent 60 years working in a Waterbury, Conn., factory. In the decade before he died, he played volleyball, went on bus tours across the Northeast, tried his luck at Atlantic City’s casinos. He deserved to retire. So why does it bother me? Is it the fact that you can’t even have a birthday without some lobbying group’s computerized mailing list seeking you out?

Perhaps it’s my resistance to joining. I don’t like the way we Americans balkanize ourselves — by race, gender, sexual preference, age or any number of demographic and cultural markers that are often the most superficial measurements of who we really are.

Understandable objections, but that’s not it. Still mystified by my resistance to opening AARP’s belated birthday card, I look to the dictionary for guidance. From the American Heritage Dictionary

I find clues that help me understand why I find AARP’s invitation so offensive. Retire means “To withdraw, as for rest or seclusion. To go to bed. To withdraw from one’s occupation, business, or office; stop working.” A fine idea. Once. Like at the turn of the last century when the average male died at the ripe old age of 45.

I have other plans. As my sixth decade approached, I decided to pretend that I was in utero once again, ready to launch on my second 50 years, an improved version in which I would avoid the excesses of my misspent youth. This fantasy isn’t inconceivable, although according to lifespan calculators on the Net, I’m being a bit optimistic.

My favorite of these digital crystal balls is The Living to 100 Life Expectancy Calculator, developed from longevity research and studies of centenarians by Thomas T. Perls and Margery Hutter Silver, two specialists in aging at Harvard Medical School.

Based on my answers to a series of pointed questions about my health and lifestyle: “Do you stay away from processed meats? Do you live near enough to other family members that you can drop by spontaneously? Do you take vitamin E (800 IU/day) and selenium (200 mcg) daily?” I can expect to live until I’m 89.208 years old. The average for males is 84.

As I approached the big day, I set a goal to lose 25 pounds. At

least I wouldn’t be fat and old. But I kept caving — to bagels and cream cheese, breakfast specials that included two eggs with sausage, grits and toast, Hershey bars with almonds, Oreo shakes at the Dairy Queen, hot cocoa with whipped cream at Barnes & Noble and the discovery that the Big Mac is actually quite tasty even if it sometimes has the consistency of the cardboard box it comes in.

Instead of my goal weight, the scale reached a figure I’d never imagined. Must I say it? 214 pounds. My body mass index was

30.7 percent. People with a BMI of 19 to 24 live longer. My body fat percentage was 29 percent. It should be 10 points lower. My total cholesterol was 205, which put me at high risk of strokes and heart attacks. My “good” cholesterol was bad, I had a chronic backache. I was, in short, a mess.

I know these facts about my body because, in a moment of pure synchronicity, Colleen, our human resources person at work, sponsored a “Wellness Day” three days before my birthday. It was a smorgasbord of mainstream and alternative health care. My feet were kneaded by a reflexologist, my hands were dipped in paraffin, I submitted to my first acupuncture treatment (it

produced a feeling of bliss that made me feel it was 1971 again) and I subjected myself to an evaluation from a team from a local hospital.

When the report came in, the news in my Personal Wellness Profile was bad — out of a possible 100, my score was a measly 37 — a discovery so dispiriting that I couldn’t even read it all the way through. God, if I didn’t use my seat belt and hadn’t stopped smoking 15 years ago, I’d have nothing going for me.

When I was 49, I thought about my next birthday almost every day: I will be 50 in six months. Five weeks. Tomorrow. I noticed that when I told people, they often expressed surprise. “You don’t look 50.”

After my birthday, they stopped saying that. I am 50 so what’s the point of pretending? So when Colleen followed up with an announcement that work would pay for anyone to join a weight-loss and exercise program, I jumped.

It’s been four weeks now on the “Choose to Lose” program, which includes a book and a Web site and has become, for the 13 of us, a religion. It takes a mainstream approach, a common-sense alternative to fat-busting pills and grapefruit diets. It’s low in fat, high in fruits, veggies and fiber and requires daily exercise. Instead of fat grams, we count fat calories. We have a daily fat budget; for me, a 5-foot-10, 214-pound male who wants to be 185 again, it’s limited to 481 fat calories a day.

Whether it will make me a pre-50 version of myself remains to be seen. We all pledged not to weigh ourselves until the program ends in April. But Choose to Lose has already transformed my eating habits, replacing my Egg McMuffins (142 fat calories) with oatmeal (25 fat calories) and my late-night Hagen Dazs Vanilla Swiss Almond (190 fat calories) with a Granny Smith apple (0).

A Choose to Lose case in point: The other day I had an hour drive back to work and was starving. Oases of fat beckoned to me from the roadside: Checkers, Dunkin Donuts, Steak ‘n Shake, a rib shack, all my old haunts. So where did I stop? Wendy’s for a baked potato, plain, zero fat calories. I did add a little margarine (60 fat calories); I’m not a masochist. And you know what? It tasted great.

More temptation loomed: a reception for editors at work. Since these were top newspaper editors the menu includes stuffed lobster tails, veal and a fat and cholesterol-laden irresistible dessert. That meant I needed exercise to get my metabolism into high gear and eat some nutritional bulwarks to steel my will at the dinner table.

Fortunately, a three-month membership at St. Anthony’s Fitness Connection is the other half of our self-improvement program. In preparation for the evening’s pigout, I treadmilled for 30 minutes and climbed stairs for 15 and then came home, dripping sweat and famished, and loaded up with a bowl of oatmeal with raisins, strawberries and fat-free milk.

That night I splurged, grazing on caviar, cheese puffs, lobster tails and veal (I did scrape the breading off) but only ate half the chocolate cheesecake, which for me is a demonstration of monumental self-control.

Can I keep this up? I hope so. Would I be doing any of this if I weren’t 50? I doubt it. There’s something about this passage that scares and saddens me. Somehow, and I can thank AARP for contributing to the feeling, the prospect of retiring signals an end that I don’t want to arrive. The days seem shorter and I want them to last longer. Eating better, feeling my thighs scream as I paddle up one more digital hill on the Stairmaster gives me hope that I can live to 100. Or at least to 89.208.

Perhaps my bias about retirement is fueled by the word’s earliest

use, etymology that lingers like linguistic DNA in our sensibilities. When the French spoke of retiring in the 1500s they were describing military forces drawing back from battle, usually in defeat. Only with the 20th century, Social Security and longer life spans, did the idea of withdrawing to relax rather than licking wounds come into vogue.

And therein, I decide, lies my problem. At 50, I’m ready to charge, even if it’s only up a Stairmaster, not retreat. I want to decide my fate or at least the parts of it I have control over. Retirement may be thrust on me by forces outside of my control — illness,

disability, corporate decisions.

So you know what? I’m not going to open the letter. I won’t shred it. I may just put it back in the mailbox with a scrawled reply on the front: “No such person.”

So thanks, AARP, but no thanks. Take this Membership Certificate and Temporary Membership Card and retire it.

Photograph by Elena Saharova courtesy of unsplash.com