mens sana in corpore sano

Etymology
From the Roman poet Juvenal (Satire X, line 356).

Proverb

 * 1) A healthy mind in a healthy body.
 * 2) * 1st–2nd c. — Juvenal, Saturae, Book IV, X, line 356.
 * "la"

- ōrandum est ut sit mēns sāna in corpore sānō

Usage notes
Over time, the phrase has come to mean that only a healthy body can produce or sustain a healthy mind – and vice versa.