This essay, discussing the pain of modern life, has this to say:
I’ve only been back at work for a few days, but already I’m noticing that the more wholesome activities are quickly dropping out of my life: walking, exercising, reading, meditating, and extra writing.
The one conspicuous similarity between these activities is that they cost little or no money, but they take time.
Suddenly I have a lot more money and a lot less time, which means I have a lot more in common with the typical working North American than I did a few months ago. While I was abroad I wouldn’t have thought twice about spending the day wandering through a national park or reading my book on the beach for a few hours. Now that kind of stuff feels like it’s out of the question. Doing either one would take most of one of my precious weekend days!
The last thing I want to do when I get home from work is exercise. It’s also the last thing I want to do after dinner or before bed or as soon as I wake, and that’s really all the time I have on a weekday.
I agree with the writer that, yes, exercising at the end of the day is not nearly as appealing in contemplation as going home and vegetating in one way or another. That said . . .
Three years ago, I enjoyed (if enjoy be the word) about 4 1/2 months of unemployment between the conclusion of my military career and the start in the civil service. This was not exactly "free time": I had a dissertation to complete and defend, and most of you know from experience that looking for a job can be a full-time job in itself. But these, and most of the honey-do home maintenance, was self-paced and only seldom involved actually going anywhere.
The result, I discovered, was a drop-off in the amount of exercise I was getting. My regular readers know that I generally maintain a pretty high level of physical fitness for a middle-aged guy. Some of this is exercise done at home (running and calisthenics), but most of it is done at the gym (weights and swimming). And trips to the gym almost always happen to and from work or during lunch at "work", by which I mean whatever 40-hour-per-week job I'm getting paid for.
Take away the job, and once the summer ended and the children weren't going to the pool anymore, the trips to the gym were reduced to approximately once per week from five days per week. In theory, I could have run more, but this didn't actually happen in practice. So my five-to-six day per week regimen became a two-to-three day per week regimen. That's not bad, probably about par for a man of my age and class. But it wasn't enough to keep from gaining about 10 pounds.
Good things tend to go together, and active people are . . . active. The psychological benefits of being gainfully employed, and the discipline of rising at 0600 for work every morning, have spill-over effects that make regular exercise easier rather than harder. Meanwhile, obesity (especially among women) and other symptoms of poor physical fitness generally, are concentrated among the lower classes, the people for whom self-discipline has always been a finite resource. The direction of causality may be mysterious, but my personal experience is that the relationship is bi-causal.