work out

Reader's Digest, March 2017の記事 'Life' にあった話です。
The ophthalmologist's very cute assistant was examining my 20-year-old grandson, when out of the blue she said, "You must really work out."
"Well, yes, I do," said my grandson, beaming. "I run and lift weights. Thank you for noticing."
"Oh, you misunderstood," she said.
"You have popped blood vessels in your eyes. We see that with people who work out."