Fitness fads vie for major moolah on ‘Sweat Inc.’

Raise your hand if remember a time before everybody walked around carrying bottles of water. The kind of “branded” water you pay for instead of just drinking the “free” stuff that comes out of taps.

The same demographic can probably recall the years when TV and radio were “free,” as well. Something you just pulled out of the air with things called “rabbit ears.”

Folks of that vintage can also remember a time before thoughts of “fitness” became all-consuming, an era when going to the gym meant something you had to do between math and history classes and usually entailed dodge ball or racking one’s brain to recall a locker combination.

Now, it seems, everyone wants to go to the gym with great frequency and pay large portions of their income for the pleasure of doing so. And stranger still, millions want to become professional fitness instructors. Time was, gym teachers were folks with medicine balls and whistles, holding down a job not necessarily associated with high social status.

But those attitudes are so 20th century. We now live in an era when companies like Soulcycle, Zumba and CrossFit attract hundreds of thousands of customers and even generate Wall Street buzz.

Is there room for another business to cash in on the next big fitness obsession? Jillian Michaels (“The Biggest Loser”) hosts “Sweat Inc.” (9 p.m., Spike), an unscripted business contest looking for the next craze worthy of huffing and puffing.

Every week, three fitness entrepreneurs will compete in a specific category. Weekly winners advance toward the finale. The winner of this variation on “Shark Tank” meets “Top Chef” in Spandex will walk away with $100,000, a chance to introduce his or her brand of exercise at an established franchise and a feature article in a health magazine.

“Frontline” (8 p.m., WKNO-TV Channel 10) presents “Immigration Battle,” a look at the history of efforts from both the White House and Congress to reform immigration policy affecting millions of undocumented Americans, their neighbors and their employers. This remains a hot-button issue certain to influence the race for the White House and the politics surrounding the search for a new Speaker of the House.