Keith Urban embraces the “physicality” of live performances. The 56-year-old singer has started a 10-date residency in Las Vegas and says that being on stage gives him “two hours of solid cardio” so he doesn’t have to completely rely on the gym. Speaking to PEOPLE, Keith said: “I love the adrenaline of a live show. I love that I get to do two hours of solid cardio on stage. I ain’t walking into a gym to do two hours of cardio. I promise you that, like ever, but I’ll do it here effortlessly and end up in really great shape.” The star – who is married to Hollywood actress Nicole Kidman – has lon…