The Twilight alum credits her slim frame to the "best jogging and hiking partners a girl could ask for"

To spice up her workout routine, Nikki Reed knew just what she needed: some paw-dorable training buddies.

“My fitness regime would suffer a great deal without these two,” the actress tells PEOPLE of her German shepherds, Enzo and Ira (pronounced Eer-rah). “They’re the best jogging and hiking partners a girl could ask for.”

But it’s not just physical activity the doggy duo excels at. Reed also praises Enzo on his snuggling ability and Ira on her singing.

“Seriously, she harmonizes with my voice when we rehearse,” the singer-actress says.

Ira joined Reed and husband Paul McDonald’s family in early 2012, a few months after the couple wed.

“My dogs are my family – my children, if you will,” Reed says. “They often dictate my life and my schedule, but their unconditional love is something I wouldn’t trade for the world.”