Deep sleep probably invalidates Wudu'
Some people may fall asleep while engaged in Dhikr (Remembrance of Allah) in the Masjid (mosque) using Misbahah (counting beads).Do they have to perform Wudu’ (ablution) before the next Salah (Prayer)?
Deep sleep is a probable annulment of Wudu’, so whoever falls into a deep sleep in a Masjid or elsewhere, has to repeat his Wudu’, whether he slept while standing, sitting, or lying down, and whether he was performing Dhikr using beads or not. If the person does not go into deep sleep i.e. has a mere gentle slumber during which he does not lose consciousness, he does not have to repeat Wudu’ based on the authentic Hadiths reported from the Prophet (peace be upon him) in this regard.
May Allah grant us success. May peace and blessings be upon our Prophet, his family and Companions