A study came out recently that showed people who retire reap many health perks. They tend to spend less time sitting and more time exercising. They sleep better and stop some of their work-related bad habits, like smoking. And they're happier.
So kudos to this jogger, who seems to be living out the retirement dream. Can you guess who this is? Two clues: That familiar grin and the Ball State t-shirt.
Yes, it's Indiana's favorite son, David Letterman! Here's how he looked BEFORE he retired.
With that big, bushy beard and the bald pate, he can totally play Santa come December!
Check out these other famous TV hosts, then and now, in the gallery below!