I don't understand this sentence

-No matter what age you are, you're probably too old to NOT
exercise.
by John Fike


I'm really confused by the saying above.
I just can't make sense of it.
Please help.

Something that's a bit closer to the idea behind the sentence might be "You're never too young to require exercise".

its basically saying,

you're never too old to exercise

(trust me, I'm a native English speaker)

It says that one should start to exercise in his mother's womb even better than at birth

Please this is as clear as filtered water.

What don't you comprehend about this phrase?

Sorry about becoming this strict, but that is how you're going to learn