(CNN) -- His name is Valor. He's half Labrador retriever, half Great Dane, and goes everywhere with Sgt. Charles Hernandez. But Valor is more than a pet -- Hernandez considers the dog a personal physician.
When Hernandez was having seizures, Valor would nibble on the side of Hernandez's leg before the veteran realized anything was wrong. And the dog pulls him away from conflicts and jumps on him during anxiety attacks to calm him down. In combination with medications, Hernandez says the dog has helped his symptoms of post-traumatic stress disorder.
"I'm alive again," says Hernandez, 49, of the Bronx, New York, now retired from the U.S. National Guard. "What keeps me going is my dog."