«Mens sana in corpore sano». in my language this popular expression translated as: in healthy body- healthy mind.

As a child I didn't pay attention to it, but with age began to notice that it works both ways. Indeed, when I'm mentally overloaded with work and tasks I get sick.

It seems in one of the stories about Sherlock Holmes, one of the characters said the phrase:

Slight cold and malaise this is only a trick, that uses weary mind to rest