Rogan looks to be dealing with digestion problems and is training his mid section(core) with heavy kettle bells. Probably also doing deadlifts from the ground. Deadlifts from the ground when you're over 50 is a stomach nightmare. He's doing all the wrong things to keep his stomach small. He also trains like a fighter 3 days a week which involves a lot of core shit. Once his ab wall splits he'll really be fucked and he'll just keep his shirt on.