I pray Salah five times. I just wanted to even I am at work, remember Allaah even I am sleeping can my heart keep remembering Allaah I mean remembrance of every times. Please reply me what do I do.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

 We ask Allaah to increase your zeal in performing acts of righteousness and accept your good deeds. The remembrance of Allaah is one of the best actions by which one gets nearer to Allaah, Allaah says (interpretation of the meaning): { …and the men and the women who remember Allaah much with their hearts and tongues Allaah has prepared for them forgiveness and a great reward (in paradise)}[33:35].

It is confirmed that a man came to the Prophet and told him: "O Prophet of Allaah! There are many principles of Islam that we are bound to stick to, inform me about something that I should stick to." The Prophet replied: "Keep your tongue busy with the remembrance of Allaah." [At-Tirmithi]

So the remembrance of Allaah is something encouraged at all times and in all circumstances except if a Muslim is in a state that is not suitable to remember Allaah, like being in the toilet, for instance. Thus, if you can remember Allaah while working, do so, if this does not preoccupy you from what is more urgent, especially the work that you are obliged to do. It is worth mentioning here that some people of knowledge stated that a Muslim is rewarded by mentioning Allaah with his tongue without the presence of the heart even though this is the lowest degree of remembrance.

Remembering Allaah while asleep is something impossible for other than the Prophets, may Allaah exalt their mention, because their eyes sleep but their hearts don't, as it is confirmed by the Prophet . However, you can mention Allaah when going to sleep and upon waking up. You have to know that if a Muslim has the intention of doing a good deed but was unable to perform it due to a given obstacle, he/she still gets its reward. The Prophet said: "If a person is sick or traveling it will be written for him the same reward as what he/she used to do when he/she is local and in good health." [Al-Bukhari]

Allaah knows best.