RESUMEN
There are six essentials [Sitta, Zarooriyah] in Unani system of medicine. These are considered to have influence on the human body with respect to preservation of health. These six essentials are: 1] Hawa-e-Muheet [Air]. 2] Makul wa Mashroob [Food and Drinks]. 3] Harkat-o-Sakoon Badni [Physical or bodily movement and repose. 4] Harkat-o-Sakoon Nafsani [Mental or Psychic movement and repose]. 5] Noum wa yaqzah [Sleep and wakefulness]. 6] Istifragh-o-Ahtibas [Evacuation and retention], Noum wa yaqzah [Sleep and wakefulness] is very essential for healthy living as it effects the health in different ways. Any disturbance in Noum wa yaqzah [Sleep and wakefulness] leads to various health related problems like stress, anxiety and may lead to psychological problems. Concept, importance and description of Noum wa yaqzah [Sleep and wakefulness] will be discussed in this paper with special reference to Unani system of medicine