It's not that I've stopped exercising. I still walk to and from work, which means that my idea of "no exercise" involves about three hours a week of walking. But I've gone from exercising five-six times a week for more than an hour, to two or three times a week for twenty to thirty minutes.
Five to six times a week for more than an hour is more ambitious than I feel. Five times a week for twenty to thirty minutes seems reasonable, though.
So I pull on a pair of jeans tight enough to demonstrate my need for more exercise, and go for a jog.
The first time I jogged a mile without pause was when I was 16.
The next time I did it, I was 35.
I can still jog over a mile, at a pace so plodding that some of my friends walk faster than it normally. I don't make it much more than a mile; a mile and a quarter, or perhaps a mile and a half if one feels generous.
Still, it's a start.