Sarah Chalke, best known for her work on Scrubs, has always been slender on-screen, but she doesn't look that way by accident, especially now.

After turning 30, Chalke says, "I had to really keep up with working out. You can't get lax about it anymore." At 32, she's looking as great as ever, so it seems she's figured out what she's got to do.

Apparently, what she has to do is mix up her workout. "If I do one thing I would get way too bored," admits Chalke. And so, she shakes it up, hiking with Lola, her chocolate lab, doing yoga, and sweating it up with boot-camp workouts.

How about you? Did you notice a change in your metabolism at a certain age?