"Not so much even in terms of how they look, but the psychological empowerment," Fonda told AP Radio. "It's like it began in the muscles and ended in the heart."
"Jane Fonda's Workout," released in 1982, spawned a series of at-home fitness programs from Fonda and competitors alike.
In it, she coined the phrase, "Feel the burn."
"In order to have an effect, I would have to work out hard enough so that I could feel the sensation that I would describe as a burn," Fonda, now 67, told AP Radio recently. "And so, go for the burn, go until you can feel that thing, and then you know it's going to make a difference."
Fonda told AP Radio that after a tour to promote her memoir, "My Life So Far," is done, she's going to have a hip replaced, though she won't say which one.
"I'm going for titanium and ceramic — and I'm looking forward to it," she said.
Her new movie, "Monster-in-Law," co-starring Jennifer Lopez, opens this month in the United States.