It is Jack LaLanne you can thank, or curse, for all the gyms: in exurban strip malls, suburban manses, downtown hotels. The health club he opened in Oakland, Calif., in 1936 was one of their seeds and templates, an endorphin emporium that pointed the way.

With “The Jack LaLanne Show,” he also had a hand in the spread — a contagion, really — of television programs exhorting viewers to rise up from their La-Z-Boys and of infomercials hawking workout equipment. An army of spandex missionaries was unleashed.

But that’s not the whole of his legacy, or the most interesting (some might say insidious) part.

That sense of failure you feel when you haven’t exercised in days? That conviction that if you could pull off better push-ups, you’d be a better person through and through? These, too, are his doing, at least in part. What he left behind when he died last week, at the toned old age of 96, was not only a sweaty culture of relentless crunching and spinning but also the notion that fitness equals character, and that self-actualization begins with the self-discipline to get and stay in shape. In the post-LaLanne landscape, it’s not the eyes but the abdominals that are windows to the soul.

“There seems to be a whole substitute morality, where your obligation is to go to the gym and not ask why,” says Mark Greif, a founding editor of the literary journal n+1 and the author of a widely discussed 2004 essay, “Against Exercise.” “If you don’t, you become a sort of villain of the culture.”