I put it all down to regular swimming at the Aquatic Centre.
Ironically, it started by accident. I meant to go aqua-jogging in the deep pool but I took a wrong turn and ended up outside at the 50m pool, where I bumped into a former football foe, looking fit as ever, the swine.
"Oh, yes," I said, slowly sucking in my stomach.
"I do a fair bit of swimming these days. Helps to keep me fit and active"
Luckily the conversation did not drag on, as I could feel myself turning blue through lack of oxygen. Worse still, my mate hung around so I had to go through the absolute torture and embarrassment of splashing up and down for a couple of lengths while he watched.
I feigned an old shoulder injury to explain why I couldn't do my normal 29 lengths and headed home.
Mrs P was her normal supportive self and expressed encouragement when I told her I'd swum a couple of lengths. Next day, she even bought me a new pair of swim shorts.
"What's wrong with my old ones?" I asked, sure that the stretchy material in them was still as strong and supportive as the day I bought them in 1985 and the pool chlorine over the years had done nothing to diminish their respectableness.
Besides, as I had gracefully aged I had discovered, er, "wobbly bits" that were easily controlled behind the stretchy shield.
A little adjustment up, tucking in, tightening of the draw string here and there and they were good as new.
Of course, I didn't want to hurt my beloved's feelings so graciously accepted the new togs and stuffed them in my bag, promising to wear them on every occasion.
I knew I wouldn't. They weren't on a first-name basis with various parts of my body like my old togs. They just wouldn't do.
Besides, my old togs made me feel young. Wearing them was like being a teenager again. Those days when trim, taut and terrific was a given, nothing sagged and confidence oozed from every pore.
I felt thus as I ambled from the main pool one afternoon, 20-odd lengths under my belt. Okay, it was five lengths, but you get the picture. I felt good.
Why not take a soak in the hot pool, I thought. So across the grass area I went, doing my best cool-dude stroll in front of the crowds, tummy sucked in (again).
The first pool was rather busy and there was one of those awkward hushes as I walked over. Feeling somewhat embarrassed and sensing I may not be welcome, I made for the second pool, where I had an enjoyable 10-minute chat with a couple of tourists.
Appropriately soothed and relaxed, I then strode back past the crowds to the changing rooms and eventually home, where I regaled Mrs P with the tale of the rude people in the hot pool.
"It was awful," I said. "It was like they didn't want to even look in my direction."
"I can't imagine what their problem was," she said, sarcastically, holding up my 1985 togs with the bum ripped clean out of them.
