04/11/2013 AT 04:30 PM EDT
is abs-olutely fabulous.
star credits her "nerdy workout" – complete with personalized soundtrack! – for helping her stay slim and impressively toned.
Russell, 37, tells Women's Health
in its May cover story that she has "this really nerdy workout I do in my walk-through closet in our brownstone. I do a workout video and use my own music – whatever is inspiring to me at that time, like Alabama Shakes, the Cure, or Mumford and Sons."
Plus, she says residing in Brooklyn offers a bonus workout – walking!
"That's one of the great things about living in Brooklyn and in New York. You get to eat a big rich fatty meal but then you can walk home," says Russell, who admits she didn't start eating vegetables until about 30. "I didn't grow up with a mom who enforced that at all."
The former Felicity
star, who is mom to daughter Willa Lou
and son River, 5, with husband Shane Deary, plays a Russian spy-next-door on the hit FX show that airs Wednesdays at 10, and when she's training for her role as Elizabeth Jennings she isn't afraid to break out of her indie workout groove.
"We did do a little fight training type stuff a few weeks before. I did get a bloody lip, which I am sort of proud about, in the boxing training. You should see the other guy though," she jokes.
The funny, self-deprecating star admits it's not easy juggling a career and motherhood, but carves out girlfriend time every few weeks and is honest about the difficulties of her competing demands.
"It's tough," Russell admits. "I try to quell my guilt by saying I'm a better mom if I'm interested in my own life. I'm not resentful. I can be really engaged when I am there. I like the yin and yang of both worlds, and I think it would be hard for me to give up either one."
But she's satisfied with her life for now, except for one thing – her rear-end. "I'm not a complainer about age. I think my girlfriends all look so much better now than they did 15 years ago. But the thing I notice most is my butt. I used to have a really good, plump butt. Ugh – now my butt's gone. I do wish I had my 25-year-old butt!"