Speaking to The Hollywood Reporter in January, Van Dyke revealed that it has to do with his workout routine. For as long as he can remember, he has worked out three times a week. Still, at age 99, he is doing the same thing.

“Somebody said, ‘To what do you attribute your age and physical condition?’” Van Dyke said. “I said, ‘I’ve always exercised three days a week.’ We go to the gym, still, three days a week, and I think that’s it.”

“If I got [to the gym] early enough, I would see you literally work out on some weight machine, and then — almost like you were doing circuit training — you would, not walk, to the next machine, but dance,” he continued. “You literally dance to the next machine! And you said that you would go the the gym and work out and then you would go home and swim laps. Then you would get back into bed and take a nap.”

Dick Van Dyke has achieved incredible things in life. As he turns triple digits, he is also releasing a book.