So the 35-year-old former star of the Sci-Fi TV drama Heroes is always prepared to break into a sweat at a moment's notice.
"From the morning through night, I just wear my workout clothes so that if I can grab a half an hour here or there "¦ then I'm ready to go," she says in a one-on-one interview at Reebok's recent launch of its RealFlex footwear, a first-of-its kind "barefoot" running shoe.
"Being a new mom, my time is of the essence."
But don't picture Larter in frumpy sweatpants and an oversized T-shirt. On this day, the five-foot-seven New Jersey native wore a sporty ruby red top with black leggings -- showing no signs of having given birth in December. Her athletic ensemble, of course, was punctuated with her pink and white Reebok RealFlex shoes.
Larter, who has been known to jog up to four times a week in LA's Runyon Canyon Park, has become a firm believer in barefoot or natural running.
"I think this is the future," she says, noting it's more than a passing trend.
"What I love about the new Reebok RealFlex sneaker is that it looks good, so you're actually dressed for the day out. But then it also helps to be anatomically correct. And I'm about alignment now. "¦ It's about putting your weight forward so you hit the muscle groups, rather than the shock of it going to your knees."
Her infant son, Theodore Hayes MacArthur, often goes along for the ride.