My dog is going to be 10 years old in October and he's still really active?

He still acts like he did when he was a young pup. He can still run very fast. He enjoys playing games with me, and play with his toys. He barks when somethings unfamiliar(I like this). I'm really happy. I've never had a dog this long. What can I do to keep him healthy? He's a chow mix. Are dogs usually this active at this age?