It says a lot about a person if they have a healthy laugh. In conversation Valerie Harper laughs frequently, joyously, deeply and infectiously.

Such as when she mentions the simple, funny coincidence that she has known two women with the rare name of Iva who have been important in her life: her mother, a one-time nurse from Lloydminster, Sask.; and her lifelong girlfriend, the actress who 45 years ago used to let Harper in on news of auditions.

Then there’s the joy of describing how at the age of 15, in 1956, she had a role as a dancer in a bizarre little black and white rock ‘n’ roll movie "with a thin little tiny plot" starring Chuck Berry and Little Richard that also featured an ingenue named Tuesday Weld. "I didn’t have a speaking role, I was dancing, but you can clearly see me in all of the scenes," she recalls.

Even discussing her efforts to watch her weight — a battle that was played out on The Mary Tyler Moore Show, where landlady Phyllis was always on the case of chubby Rhoda, played by Harper, until like a swan Rhoda emerged newly thin and gorgeous — there is friendly, self-deprecating humour. "It’s a real problem in terms of, I just could overeat so easily and be as big as a house."

The ostensible goal of the interview was to learn how Harper, at 64, manages to stay fit and healthy, maintain a glowing and handsome, even beautiful, complexion, and find the energy needed to take to the stage every night in her touring one-woman show playing Israeli hero Golda Meir.

Harper patiently outlined the exercise routines, diet and face cream that are part of her weekly regimen, but over the course of two conversations, from hotels in Cincinnati and Philadelphia, she revealed a lot more. Harper is proof that superficial qualities like nice looks and a good figure are much less important to achieving healthy aging than maintaining an active mind, seeking new challenges, relying on a network of close friends, finding support in a loving romantic relationship and, yes, remembering to laugh.

Harper, born in northern New York state to that Canadian-born mother and a hockey-playing father from Washington state, has forged a career, first as a dancer then as a character actress, that has lasted 50 years, with her greatest success coming as the Jewish window dresser Rhoda Morgenstern in first the Mary Tyler Moore Show and then Rhoda, from 1970-78. Rhoda's wedding to Joe in 1974 was watched by 50-million viewers, one of the largest TV audiences in history.

In later years she has appeared on numerous TV programs, in some films and on stage, notably in the 1990s in another one-woman play that she co-wrote based on the life of U.S. human-rights advocate and feminist Pearl. S. Buck. She still resurrects it occasionally. "My mother loved Pearl," she confides.

Golda’s Balcony, written by William Gibson (The Miracle Worker), had a successful run on Broadway and, last year, the producers approached Harper to take it on the road. The tour started in October and will run through the spring, with appearances in Columbus, Detroit, Cleveland, Chicago and Toronto, among other cities.

The paradoxes of Harper’s life seem to converge as she discusses playing Meir, the Israeli Prime Minister who led her nation through the Yom Kippur War of 1973.

The comedian with the quick and hearty laugh has exercised a strong social conscience throughout her adult years, marching with Martin Luther King, fighting for the Equal Rights Amendment and against child poverty, supporting Cesar Chavez and the United Farm Workers, and working for the Congress of Racial Equality.

And then there’s religion. Most people assume she’s Jewish. But the woman who played one of TV’s strongest Jewish characters on Rhoda and who is now cast as an Israeli hero, who even calls herself a Zionist, was raised Catholic — sort of.

"My mother was United Church of Canada, but because she had to go to church three times a day and cook dinner, Sunday was a horror for her, so she said, I’ll never push my kids into religion. We went to the Catholic school as little ones, and of course I didn’t want to burn in hell, so the three of us converted.

"By the time I was 15 I became agnostic. I respect all religions, I think they are marvellous for people if it serves them, but I am agnostic."

Her feminist leanings led her to her initial appreciation of Golda Meir.

"She was a hero of mine in the sixties, and in the women’s movement there was a wonderful poster that had Golda’s face, which was like no-one else’s, completely recognizable, and under it it said, But can she type?" (She laughs.)

She visited Israel in the 1970s and remains a strong defender of the Jewish state. "Anybody who is not a Zionist is not looking clearly at the world or at history."

A Jewish friend, Penny Almog, served as the model for the voice of Rhoda, and she remains one of four close girlfriends who are always available for support if Harper feels the need. Also on speed-dial is her daughter Cristina, 22. And always nearby is her husband of 20 years, Tony Cacciotti, 65, whom Harper obviously adores. She frequently quotes his advice on diet, exercise, even cosmetic surgery.

It all seems to add up to a rich and stimulating life for the woman who doesn’t shy away from a fight, such as the well-publicized election battle she lost for the Screen Actors Guild presidency in 2001.

"Here’s what I do. The heartbreakingness of the world, I always see the possibility for transformation. The idea of infinite possibility lives very strongly in me. Because like Golda," she said, "we cannot afford to be pessimists, we’ll be down for the count."