Nashville 10 p.m., Channel 5
Want to hear something cute? The girls who play Rayna’s daughters are real-life sisters, Lennon and Maisy Stella (pictured). They perform together as a singing duo, as we saw last week with their sweet version of the Lumineers’ “Ho Hey,” and they had a viral hit last year (more than 15 million views) with a version of Robyn’s “Call Your Girlfriend.” They were raised on a farm outside of Toronto. By the way, why did the writers bring in Gunnar’s brother to create triangular tension, then kill him off, then bring in Chris Carmack to create triangular tension? Strange.
The Truth About Exercise With Michael Mosley 10 p.m., Channel 2
What, Richard Simmons wasn’t available? British journalist Michael Mosley (pictured) looks at the latest scientific discoveries about working out, and the possibility of customizing our exercise routines to fit our DNA. One scenario has people benefiting from only three minutes of high-intensity exercise a week. Sounds like a perfect plan.
My Crazy Obsession 10 p.m., TLC
She like-likes Barbie.
Toy Hunter 9 p.m., Travel Channel
Gene Simmons wants Demon dolls.
Criminal Minds 9 p.m., Channel 4
A time capsule is opened, and, well, you know.Matthew Gilbert can be reached at firstname.lastname@example.org. Follow him on Twitter @MatthewGilbert.