Response: Sleeping while in a sitting up position does not annul ablution, whereas it will be annulled due to sleeping on a side or lying down. In those two positions one is not capable of self-control. This rule stems from the attitude of the Prophet’s (PAPBUH) companions (may Allah be pleased with them) who used to wait for prayer time with the Prophet (PAPBUH) when their heads fall due to sleeping sitting down. Then they stand up and pray. Sheikh Saleh Ibn Fawzan Alfawzan 14/6/1422 H