Is this normal for a min pin?

Rudy just turned two in May, and my mom has been concerned that there is something wrong with him because he sleeps so much.As i'm typing, he's asleep on my lap.He has tons of energy when he's awake.We jog together around my neighborhood, and is very healthy. He's not lethargic, but he falls asleep real easy.Could it just be that he wears himself out & might be bored or could something be wrong?