The Prophet Muhammad (peace be upon him) once asked a companion:
"(Is it true) that you fast all day and stand in prayer all night?" The companion replied that the report was indeed true.
The Prophet then said: "Do not do that! Observe the fast sometimes and also leave (it) at other times; stand up for prayer at night and also sleep at night. Your body has a right over you, your eyes have a right over you and your wife has a right over you."
Sahih Al-Bukhari
