Often enough I simply attributed the claim to pious exaggeration - I mean, really, that would only leave a few hours for sleep, food and other duties - and then I read this in Fr. Rutler's biography of the holy man:
The Curé never left the church before ten and sometimes remained until midnight. He was back at the stroke of one. This means he slept two hours at most before beginning a new day. And he did this seven days a week for thirty years (189).That certainly is a special grace from the Lord.
In college, I had a professor with a similar grace: he slept only three hours each night.
It is a grace, frankly, I am glad the Lord has not seen fit to grant me; I like my sleep, but not more than about six and a half hours.