Cats dialing 9-1-1, dogs dragging infants to safety: These days, pets are truly earning their keep. But for people with HIV, Fido and FiFi have long offered a new leash on life. A Multicenter AIDS Cohort study of more than 2,000 positive people reports that pet owners experience fewer bouts of depression, among other health benefits.

Kim Olivares, for instance, was diagnosed in 1993 and fell into a deep funk that worsened when her son moved out. “I turned into a lump on the couch and isolated myself,” says Olivares, now 50, who lives in Half Moon Bay, California. “I took comfort in food and gained 30 pounds.” Enter Spot, a feisty pit bull, who yanked her from the sofa. “I first walked Spot a lot to tire him out, so he’d stop chewing my orchids,” she says. As he grew, they’d clock three to four miles each day, and Olivares watched the weight melt off. Staying active also helps her manage elevated cholesterol from meds, as well as high blood pressure.

“The responsibility of having a pet can motivate us to take care of ourselves,” says Victor Spain, a veterinary epidemiologist who works with Pets Are Wonderful Support (PAWS) in San Francisco, an organization that serves HIV positive pet owners. San Francisco patient Eric Skiver, 46, agrees, saying of his Jack Russell terrier, Boner: “This dog’s unconditional love has given me the will to go on.”

Pets also facilitate social interaction, Spain adds. Ask Blake Velde, 47, who lives with Jake, a poodle–Lhasa apso mix, and Jessie, a Westie, in Arlington, Virginia. The pooches helped him meet neighbors. “Most of us have dogs, and we met on walks,” he says. “It helps me feel welcome.” Olivares feels more welcome, confident and attractive, too. Call it puppy love.