There’s a point in your 30s where you realize your body doesn’t handle things like jumping, running, sleeping, digesting and burning off unhealthy foods, and recovering from hangovers like it used to.

And now scientists have figured out when and why that happens.

A new study found that our bodies don’t really age gradually . . . the researchers found there are really three ages where our bodies make a big shift to their next, older stage.

And those ages are:  34 . . . 60 . . . and 78.

The researchers have also tied those big aging jumps to the protein levels in our blood.  So their next mission is . . . figuring out if there’s a way to use that knowledge to counteract and slow down the aging process.